/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2011 NetApp, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */
/* This file is dual-licensed; see usr/src/contrib/bhyve/LICENSE */

/*
 * Copyright 2015 Pluribus Networks Inc.
 * Copyright 2018 Joyent, Inc.
 * Copyright 2025 Oxide Computer Company
 * Copyright 2021 OmniOS Community Edition (OmniOSce) Association.
 */


#include <sys/cdefs.h>

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/sysctl.h>
#include <sys/kmem.h>
#include <sys/pcpu.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/rwlock.h>
#include <sys/sched.h>
#include <sys/systm.h>
#include <sys/sunddi.h>
#include <sys/hma.h>
#include <sys/archsystm.h>

#include <machine/md_var.h>
#include <x86/psl.h>
#include <x86/apicreg.h>

#include <machine/specialreg.h>
#include <machine/vmm.h>
#include <machine/vmm_dev.h>
#include <machine/vmparam.h>
#include <sys/vmm_instruction_emul.h>
#include <sys/vmm_vm.h>
#include <sys/vmm_gpt.h>
#include <sys/vmm_data.h>

#include "vmm_ioport.h"
#include "vmm_host.h"
#include "vmm_util.h"
#include "vatpic.h"
#include "vatpit.h"
#include "vhpet.h"
#include "vioapic.h"
#include "vlapic.h"
#include "vpmtmr.h"
#include "vrtc.h"
#include "vmm_stat.h"
#include "vmm_lapic.h"

#include "io/ppt.h"
#include "io/iommu.h"

struct vlapic;

/* Flags for vtc_status */
#define VTCS_FPU_RESTORED       1 /* guest FPU restored, host FPU saved */
#define VTCS_FPU_CTX_CRITICAL   2 /* in ctx where FPU restore cannot be lazy */

typedef struct vm_thread_ctx {
        struct vm       *vtc_vm;
        int             vtc_vcpuid;
        uint_t          vtc_status;
        enum vcpu_ustate vtc_ustate;
} vm_thread_ctx_t;

#define VMM_MTRR_VAR_MAX 10
#define VMM_MTRR_DEF_MASK \
        (MTRR_DEF_ENABLE | MTRR_DEF_FIXED_ENABLE | MTRR_DEF_TYPE)
#define VMM_MTRR_PHYSBASE_MASK (MTRR_PHYSBASE_PHYSBASE | MTRR_PHYSBASE_TYPE)
#define VMM_MTRR_PHYSMASK_MASK (MTRR_PHYSMASK_PHYSMASK | MTRR_PHYSMASK_VALID)
struct vm_mtrr {
        uint64_t def_type;
        uint64_t fixed4k[8];
        uint64_t fixed16k[2];
        uint64_t fixed64k;
        struct {
                uint64_t base;
                uint64_t mask;
        } var[VMM_MTRR_VAR_MAX];
};

/*
 * Initialization:
 * (a) allocated when vcpu is created
 * (i) initialized when vcpu is created and when it is reinitialized
 * (o) initialized the first time the vcpu is created
 * (x) initialized before use
 */
struct vcpu {
        /* (o) protects state, run_state, hostcpu, sipi_vector */
        kmutex_t        lock;

        enum vcpu_state state;          /* (o) vcpu state */
        enum vcpu_run_state run_state;  /* (i) vcpu init/sipi/run state */
        kcondvar_t      vcpu_cv;        /* (o) cpu waiter cv */
        kcondvar_t      state_cv;       /* (o) IDLE-transition cv */
        int             hostcpu;        /* (o) vcpu's current host cpu */
        int             lastloccpu;     /* (o) last host cpu localized to */
        bool            reqidle;        /* (i) request vcpu to idle */
        bool            reqconsist;     /* (i) req. vcpu exit when consistent */
        bool            reqbarrier;     /* (i) request vcpu exit barrier */
        struct vlapic   *vlapic;        /* (i) APIC device model */
        enum x2apic_state x2apic_state; /* (i) APIC mode */
        uint64_t        exit_intinfo;   /* (i) events pending at VM exit */
        uint64_t        exc_pending;    /* (i) exception pending */
        bool            nmi_pending;    /* (i) NMI pending */
        bool            extint_pending; /* (i) INTR pending */

        uint8_t         sipi_vector;    /* (i) SIPI vector */
        hma_fpu_t       *guestfpu;      /* (a,i) guest fpu state */
        uint64_t        guest_xcr0;     /* (i) guest %xcr0 register */
        void            *stats;         /* (a,i) statistics */
        struct vm_exit  exitinfo;       /* (x) exit reason and collateral */
        uint64_t        nextrip;        /* (x) next instruction to execute */
        struct vie      *vie_ctx;       /* (x) instruction emulation context */
        vm_client_t     *vmclient;      /* (a) VM-system client */
        uint64_t        tsc_offset;     /* (x) vCPU TSC offset */
        struct vm_mtrr  mtrr;           /* (i) vcpu's MTRR */
        vcpu_cpuid_config_t cpuid_cfg;  /* (x) cpuid configuration */

        enum vcpu_ustate ustate;        /* (i) microstate for the vcpu */
        hrtime_t        ustate_when;    /* (i) time of last ustate change */
        uint64_t ustate_total[VU_MAX];  /* (o) total time spent in ustates */
        vm_thread_ctx_t vtc;            /* (o) thread state for ctxops */
        struct ctxop    *ctxop;         /* (o) ctxop storage for vcpu */
};

#define vcpu_lock(v)            mutex_enter(&((v)->lock))
#define vcpu_unlock(v)          mutex_exit(&((v)->lock))
#define vcpu_assert_locked(v)   ASSERT(MUTEX_HELD(&((v)->lock)))

struct mem_seg {
        size_t  len;
        bool    sysmem;
        vm_object_t *object;
};
#define VM_MAX_MEMSEGS  5

struct mem_map {
        vm_paddr_t      gpa;
        size_t          len;
        uintptr_t       segoff;
        int             segid;
        int             prot;
        int             flags;
};
#define VM_MAX_MEMMAPS  8

/* Arbitrary limit on entries per VM */
static uint_t mmiohook_entry_limit = 64;

typedef struct mmiohook_entry {
        mmio_handler_t          mhe_func;
        void                    *mhe_arg;
        uint64_t                mhe_addr;
        uint32_t                mhe_size;
        uint32_t                mhe_pad;
} mmiohook_entry_t;

struct mmiohook_config {
        mmiohook_entry_t        *mhc_entries;
        uint_t                  mhc_count;
};

/*
 * Initialization:
 * (o) initialized the first time the VM is created
 * (i) initialized when VM is created and when it is reinitialized
 * (x) initialized before use
 */
struct vm {
        void            *cookie;                /* (i) cpu-specific data */
        void            *iommu;                 /* (x) iommu-specific data */
        struct vhpet    *vhpet;                 /* (i) virtual HPET */
        struct vioapic  *vioapic;               /* (i) virtual ioapic */
        struct vatpic   *vatpic;                /* (i) virtual atpic */
        struct vatpit   *vatpit;                /* (i) virtual atpit */
        struct vpmtmr   *vpmtmr;                /* (i) virtual ACPI PM timer */
        struct vrtc     *vrtc;                  /* (o) virtual RTC */
        volatile cpuset_t active_cpus;          /* (i) active vcpus */
        volatile cpuset_t debug_cpus;           /* (i) vcpus stopped for dbg */
        volatile cpuset_t halted_cpus;          /* (x) cpus in a hard halt */
        int             suspend_how;            /* (i) stop VM execution */
        int             suspend_source;         /* (i) src vcpuid of suspend */
        hrtime_t        suspend_when;           /* (i) time suspend asserted */
        struct mem_map  mem_maps[VM_MAX_MEMMAPS]; /* (i) guest address space */
        struct mem_seg  mem_segs[VM_MAX_MEMSEGS]; /* (o) guest memory regions */
        struct vmspace  *vmspace;               /* (o) guest's address space */
        struct vcpu     vcpu[VM_MAXCPU];        /* (i) guest vcpus */
        /* The following describe the vm cpu topology */
        uint16_t        sockets;                /* (o) num of sockets */
        uint16_t        cores;                  /* (o) num of cores/socket */
        uint16_t        threads;                /* (o) num of threads/core */
        uint16_t        maxcpus;                /* (o) max pluggable cpus */

        hrtime_t        boot_hrtime;            /* (i) hrtime at VM boot */

        /* TSC and TSC scaling related values */
        uint64_t        tsc_offset;             /* (i) VM-wide TSC offset */
        uint64_t        guest_freq;             /* (i) guest TSC Frequency */
        uint64_t        freq_multiplier;        /* (i) guest/host TSC Ratio */

        struct ioport_config ioports;           /* (o) ioport handling */
        struct mmiohook_config mmiohooks;       /* (o) MMIO hooks */

        bool            mem_transient;          /* (o) alloc transient memory */
        bool            is_paused;              /* (i) instance is paused */
};

static int vmm_initialized;
static uint64_t vmm_host_freq;


static void
nullop_panic(void)
{
        panic("null vmm operation call");
}

/* Do not allow use of an un-set `ops` to do anything but panic */
static struct vmm_ops vmm_ops_null = {
        .init           = (vmm_init_func_t)nullop_panic,
        .resume         = (vmm_resume_func_t)nullop_panic,
        .vminit         = (vmi_init_func_t)nullop_panic,
        .vmrun          = (vmi_run_func_t)nullop_panic,
        .vmcleanup      = (vmi_cleanup_func_t)nullop_panic,
        .vmgetreg       = (vmi_get_register_t)nullop_panic,
        .vmsetreg       = (vmi_set_register_t)nullop_panic,
        .vmgetdesc      = (vmi_get_desc_t)nullop_panic,
        .vmsetdesc      = (vmi_set_desc_t)nullop_panic,
        .vmgetcap       = (vmi_get_cap_t)nullop_panic,
        .vmsetcap       = (vmi_set_cap_t)nullop_panic,
        .vlapic_init    = (vmi_vlapic_init)nullop_panic,
        .vlapic_cleanup = (vmi_vlapic_cleanup)nullop_panic,
        .vmpause        = (vmi_pause_t)nullop_panic,
        .vmsavectx      = (vmi_savectx)nullop_panic,
        .vmrestorectx   = (vmi_restorectx)nullop_panic,
        .vmgetmsr       = (vmi_get_msr_t)nullop_panic,
        .vmsetmsr       = (vmi_set_msr_t)nullop_panic,
        .vmfreqratio    = (vmi_freqratio_t)nullop_panic,
        .fr_fracsize    = 0,
        .fr_intsize     = 0,
};

static struct vmm_ops *ops = &vmm_ops_null;

#define VMM_INIT()                      ((*ops->init)())
#define VMM_RESUME()                    ((*ops->resume)())

#define VMINIT(vm)              ((*ops->vminit)(vm))
#define VMRUN(vmi, vcpu, rip)   ((*ops->vmrun)(vmi, vcpu, rip))
#define VMCLEANUP(vmi)                  ((*ops->vmcleanup)(vmi))

#define VMGETREG(vmi, vcpu, num, rv)    ((*ops->vmgetreg)(vmi, vcpu, num, rv))
#define VMSETREG(vmi, vcpu, num, val)   ((*ops->vmsetreg)(vmi, vcpu, num, val))
#define VMGETDESC(vmi, vcpu, num, dsc)  ((*ops->vmgetdesc)(vmi, vcpu, num, dsc))
#define VMSETDESC(vmi, vcpu, num, dsc)  ((*ops->vmsetdesc)(vmi, vcpu, num, dsc))
#define VMGETCAP(vmi, vcpu, num, rv)    ((*ops->vmgetcap)(vmi, vcpu, num, rv))
#define VMSETCAP(vmi, vcpu, num, val)   ((*ops->vmsetcap)(vmi, vcpu, num, val))
#define VLAPIC_INIT(vmi, vcpu)          ((*ops->vlapic_init)(vmi, vcpu))
#define VLAPIC_CLEANUP(vmi, vlapic)     ((*ops->vlapic_cleanup)(vmi, vlapic))

#define fpu_start_emulating()   load_cr0(rcr0() | CR0_TS)
#define fpu_stop_emulating()    clts()

SDT_PROVIDER_DEFINE(vmm);

SYSCTL_NODE(_hw, OID_AUTO, vmm, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
    NULL);

/*
 * Halt the guest if all vcpus are executing a HLT instruction with
 * interrupts disabled.
 */
int halt_detection_enabled = 1;

/* Trap into hypervisor on all guest exceptions and reflect them back */
int trace_guest_exceptions;

/* Trap WBINVD and ignore it */
int trap_wbinvd = 1;

static void vm_free_memmap(struct vm *vm, int ident);
static bool sysmem_mapping(struct vm *vm, struct mem_map *mm);
static void vcpu_notify_event_locked(struct vcpu *vcpu, vcpu_notify_t);
static bool vcpu_sleep_bailout_checks(struct vm *vm, int vcpuid);
static int vcpu_vector_sipi(struct vm *vm, int vcpuid, uint8_t vector);
static bool vm_is_suspended(struct vm *, struct vm_exit *);
static void vm_mmiohook_init(struct vm *, struct mmiohook_config *);
static void vm_mmiohook_cleanup(struct vm *, struct mmiohook_config *);

static void vmm_savectx(void *);
static void vmm_restorectx(void *);
static const struct ctxop_template vmm_ctxop_tpl = {
        .ct_rev         = CTXOP_TPL_REV,
        .ct_save        = vmm_savectx,
        .ct_restore     = vmm_restorectx,
};

static uint64_t calc_tsc_offset(uint64_t base_host_tsc, uint64_t base_guest_tsc,
    uint64_t mult);
static uint64_t calc_guest_tsc(uint64_t host_tsc, uint64_t mult,
    uint64_t offset);

/* functions implemented in vmm_time_support.S */
uint64_t calc_freq_multiplier(uint64_t guest_hz, uint64_t host_hz,
    uint32_t frac_size);
uint64_t scale_tsc(uint64_t tsc, uint64_t multiplier, uint32_t frac_size);

#ifdef KTR
static const char *
vcpu_state2str(enum vcpu_state state)
{

        switch (state) {
        case VCPU_IDLE:
                return ("idle");
        case VCPU_FROZEN:
                return ("frozen");
        case VCPU_RUNNING:
                return ("running");
        case VCPU_SLEEPING:
                return ("sleeping");
        default:
                return ("unknown");
        }
}
#endif

static void
vcpu_cleanup(struct vm *vm, int i, bool destroy)
{
        struct vcpu *vcpu = &vm->vcpu[i];

        VLAPIC_CLEANUP(vm->cookie, vcpu->vlapic);
        if (destroy) {
                vmm_stat_free(vcpu->stats);

                vcpu_cpuid_cleanup(&vcpu->cpuid_cfg);

                hma_fpu_free(vcpu->guestfpu);
                vcpu->guestfpu = NULL;

                vie_free(vcpu->vie_ctx);
                vcpu->vie_ctx = NULL;

                vmc_destroy(vcpu->vmclient);
                vcpu->vmclient = NULL;

                ctxop_free(vcpu->ctxop);
                mutex_destroy(&vcpu->lock);
        }
}

static void
vcpu_init(struct vm *vm, int vcpu_id, bool create)
{
        struct vcpu *vcpu;

        KASSERT(vcpu_id >= 0 && vcpu_id < vm->maxcpus,
            ("vcpu_init: invalid vcpu %d", vcpu_id));

        vcpu = &vm->vcpu[vcpu_id];

        if (create) {
                mutex_init(&vcpu->lock, NULL, MUTEX_ADAPTIVE, NULL);

                vcpu->state = VCPU_IDLE;
                vcpu->hostcpu = NOCPU;
                vcpu->lastloccpu = NOCPU;
                vcpu->guestfpu = hma_fpu_alloc(KM_SLEEP);
                vcpu->stats = vmm_stat_alloc();
                vcpu->vie_ctx = vie_alloc();
                vcpu_cpuid_init(&vcpu->cpuid_cfg);

                vcpu->ustate = VU_INIT;
                vcpu->ustate_when = gethrtime();

                vcpu->vtc.vtc_vm = vm;
                vcpu->vtc.vtc_vcpuid = vcpu_id;
                vcpu->ctxop = ctxop_allocate(&vmm_ctxop_tpl, &vcpu->vtc);
        } else {
                vie_reset(vcpu->vie_ctx);
                bzero(&vcpu->exitinfo, sizeof (vcpu->exitinfo));
                vcpu_ustate_change(vm, vcpu_id, VU_INIT);
                bzero(&vcpu->mtrr, sizeof (vcpu->mtrr));
        }

        vcpu->run_state = VRS_HALT;
        vcpu->vlapic = VLAPIC_INIT(vm->cookie, vcpu_id);
        (void) vm_set_x2apic_state(vm, vcpu_id, X2APIC_DISABLED);
        vcpu->reqidle = false;
        vcpu->reqconsist = false;
        vcpu->reqbarrier = false;
        vcpu->exit_intinfo = 0;
        vcpu->nmi_pending = false;
        vcpu->extint_pending = false;
        vcpu->exc_pending = 0;
        vcpu->guest_xcr0 = XFEATURE_ENABLED_X87;
        (void) hma_fpu_init(vcpu->guestfpu);
        vmm_stat_init(vcpu->stats);
        vcpu->tsc_offset = 0;
}

int
vcpu_trace_exceptions(struct vm *vm, int vcpuid)
{
        return (trace_guest_exceptions);
}

int
vcpu_trap_wbinvd(struct vm *vm, int vcpuid)
{
        return (trap_wbinvd);
}

struct vm_exit *
vm_exitinfo(struct vm *vm, int cpuid)
{
        struct vcpu *vcpu;

        if (cpuid < 0 || cpuid >= vm->maxcpus)
                panic("vm_exitinfo: invalid cpuid %d", cpuid);

        vcpu = &vm->vcpu[cpuid];

        return (&vcpu->exitinfo);
}

struct vie *
vm_vie_ctx(struct vm *vm, int cpuid)
{
        if (cpuid < 0 || cpuid >= vm->maxcpus)
                panic("vm_vie_ctx: invalid cpuid %d", cpuid);

        return (vm->vcpu[cpuid].vie_ctx);
}

static int
vmm_init(void)
{
        vmm_host_state_init();
        vmm_host_freq = unscalehrtime(NANOSEC);

        if (vmm_is_intel()) {
                ops = &vmm_ops_intel;
        } else if (vmm_is_svm()) {
                ops = &vmm_ops_amd;
        } else {
                return (ENXIO);
        }

        if (!vmm_vm_init()) {
                return (ENXIO);
        }
        const int err = VMM_INIT();
        if (err != 0) {
                vmm_vm_fini();
                ops = &vmm_ops_null;
                return (err);
        }

        return (0);
}

int
vmm_mod_load()
{
        VERIFY(vmm_initialized == 0);

        const int err = vmm_init();
        if (err == 0) {
                vmm_initialized = 1;
        }

        return (err);
}

void
vmm_mod_unload()
{
        VERIFY(vmm_initialized == 1);

        vmm_vm_fini();

        vmm_initialized = 0;
}

/*
 * Create a test IOMMU domain to see if the host system has necessary hardware
 * and drivers to do so.
 */
bool
vmm_check_iommu(void)
{
        void *domain;
        const size_t arb_test_sz = (1UL << 32);

        domain = iommu_create_domain(arb_test_sz);
        if (domain == NULL) {
                return (false);
        }
        iommu_destroy_domain(domain);
        return (true);
}

static void
vm_init(struct vm *vm, bool create)
{
        int i;

        vm->cookie = VMINIT(vm);
        vm->iommu = NULL;
        vm->vioapic = vioapic_init(vm);
        vm->vhpet = vhpet_init(vm);
        vm->vatpic = vatpic_init(vm);
        vm->vatpit = vatpit_init(vm);
        vm->vpmtmr = vpmtmr_init(vm);
        if (create)
                vm->vrtc = vrtc_init(vm);

        vm_inout_init(vm, &vm->ioports);
        vm_mmiohook_init(vm, &vm->mmiohooks);

        CPU_ZERO(&vm->active_cpus);
        CPU_ZERO(&vm->debug_cpus);

        vm->suspend_how = 0;
        vm->suspend_source = 0;
        vm->suspend_when = 0;

        for (i = 0; i < vm->maxcpus; i++)
                vcpu_init(vm, i, create);

        /*
         * Configure VM time-related data, including:
         * - VM-wide TSC offset
         * - boot_hrtime
         * - guest_freq (same as host at boot time)
         * - freq_multiplier (used for scaling)
         *
         * This data is configured such that the call to vm_init() represents
         * the boot time (when the TSC(s) read 0).  Each vCPU will have its own
         * offset from this, which is altered if/when the guest writes to
         * MSR_TSC.
         *
         * Further changes to this data may occur if userspace writes to the
         * time data.
         */
        const uint64_t boot_tsc = rdtsc_offset();

        /* Convert the boot TSC reading to hrtime */
        vm->boot_hrtime = (hrtime_t)boot_tsc;
        scalehrtime(&vm->boot_hrtime);

        /* Guest frequency is the same as the host at boot time */
        vm->guest_freq = vmm_host_freq;

        /* no scaling needed if guest_freq == host_freq */
        vm->freq_multiplier = VM_TSCM_NOSCALE;

        /* configure VM-wide offset: initial guest TSC is 0 at boot */
        vm->tsc_offset = calc_tsc_offset(boot_tsc, 0, vm->freq_multiplier);
}

/*
 * The default CPU topology is a single thread per package.
 */
uint_t cores_per_package = 1;
uint_t threads_per_core = 1;

int
vm_create(uint64_t flags, struct vm **retvm)
{
        struct vm *vm;
        struct vmspace *vmspace;

        /*
         * If vmm.ko could not be successfully initialized then don't attempt
         * to create the virtual machine.
         */
        if (!vmm_initialized)
                return (ENXIO);

        vmspace = vmspace_alloc(VM_MAXUSER_ADDRESS);
        if (vmspace == NULL) {
                return (ENOMEM);
        }

        if ((flags & VCF_TRACK_DIRTY) != 0) {
                if (vmspace_set_tracking(vmspace, true) != 0) {
                        vmspace_destroy(vmspace);
                        return (ENOTSUP);
                }
        }

        vm = kmem_zalloc(sizeof (struct vm), KM_SLEEP);

        vm->vmspace = vmspace;
        vm->mem_transient = (flags & VCF_RESERVOIR_MEM) == 0;
        for (uint_t i = 0; i < VM_MAXCPU; i++) {
                vm->vcpu[i].vmclient = vmspace_client_alloc(vmspace);
        }

        vm->sockets = 1;
        vm->cores = cores_per_package;  /* XXX backwards compatibility */
        vm->threads = threads_per_core; /* XXX backwards compatibility */
        vm->maxcpus = VM_MAXCPU;        /* XXX temp to keep code working */

        vm_init(vm, true);

        *retvm = vm;
        return (0);
}

void
vm_get_topology(struct vm *vm, uint16_t *sockets, uint16_t *cores,
    uint16_t *threads, uint16_t *maxcpus)
{
        *sockets = vm->sockets;
        *cores = vm->cores;
        *threads = vm->threads;
        *maxcpus = vm->maxcpus;
}

uint16_t
vm_get_maxcpus(struct vm *vm)
{
        return (vm->maxcpus);
}

int
vm_set_topology(struct vm *vm, uint16_t sockets, uint16_t cores,
    uint16_t threads, uint16_t maxcpus)
{
        if (maxcpus != 0)
                return (EINVAL);        /* XXX remove when supported */
        if ((sockets * cores * threads) > vm->maxcpus)
                return (EINVAL);
        /* XXX need to check sockets * cores * threads == vCPU, how? */
        vm->sockets = sockets;
        vm->cores = cores;
        vm->threads = threads;
        vm->maxcpus = VM_MAXCPU;        /* XXX temp to keep code working */
        return (0);
}

static void
vm_cleanup(struct vm *vm, bool destroy)
{
        struct mem_map *mm;
        int i;

        ppt_unassign_all(vm);

        if (vm->iommu != NULL)
                iommu_destroy_domain(vm->iommu);

        /*
         * Devices which attach their own ioport hooks should be cleaned up
         * first so they can tear down those registrations.
         */
        vpmtmr_cleanup(vm->vpmtmr);

        vm_inout_cleanup(vm, &vm->ioports);
        vm_mmiohook_cleanup(vm, &vm->mmiohooks);

        if (destroy)
                vrtc_cleanup(vm->vrtc);
        else
                vrtc_reset(vm->vrtc);

        vatpit_cleanup(vm->vatpit);
        vhpet_cleanup(vm->vhpet);
        vatpic_cleanup(vm->vatpic);
        vioapic_cleanup(vm->vioapic);

        for (i = 0; i < vm->maxcpus; i++)
                vcpu_cleanup(vm, i, destroy);

        VMCLEANUP(vm->cookie);

        /*
         * System memory is removed from the guest address space only when
         * the VM is destroyed. This is because the mapping remains the same
         * across VM reset.
         *
         * Device memory can be relocated by the guest (e.g. using PCI BARs)
         * so those mappings are removed on a VM reset.
         */
        for (i = 0; i < VM_MAX_MEMMAPS; i++) {
                mm = &vm->mem_maps[i];
                if (destroy || !sysmem_mapping(vm, mm)) {
                        vm_free_memmap(vm, i);
                } else {
                        /*
                         * We need to reset the IOMMU flag so this mapping can
                         * be reused when a VM is rebooted. Since the IOMMU
                         * domain has already been destroyed we can just reset
                         * the flag here.
                         */
                        mm->flags &= ~VM_MEMMAP_F_IOMMU;
                }
        }

        if (destroy) {
                for (i = 0; i < VM_MAX_MEMSEGS; i++)
                        vm_free_memseg(vm, i);

                vmspace_destroy(vm->vmspace);
                vm->vmspace = NULL;
        }
}

void
vm_destroy(struct vm *vm)
{
        vm_cleanup(vm, true);
        kmem_free(vm, sizeof (*vm));
}

int
vm_reinit(struct vm *vm, uint64_t flags)
{
        vm_cleanup(vm, false);
        vm_init(vm, false);
        return (0);
}

bool
vm_is_paused(struct vm *vm)
{
        return (vm->is_paused);
}

int
vm_pause_instance(struct vm *vm)
{
        if (vm->is_paused) {
                return (EALREADY);
        }
        vm->is_paused = true;

        for (uint_t i = 0; i < vm->maxcpus; i++) {
                struct vcpu *vcpu = &vm->vcpu[i];

                if (!CPU_ISSET(i, &vm->active_cpus)) {
                        continue;
                }
                vlapic_pause(vcpu->vlapic);

                /*
                 * vCPU-specific pause logic includes stashing any
                 * to-be-injected events in exit_intinfo where it can be
                 * accessed in a manner generic to the backend.
                 */
                ops->vmpause(vm->cookie, i);
        }
        vhpet_pause(vm->vhpet);
        vatpit_pause(vm->vatpit);
        vrtc_pause(vm->vrtc);

        return (0);
}

int
vm_resume_instance(struct vm *vm)
{
        if (!vm->is_paused) {
                return (EALREADY);
        }
        vm->is_paused = false;

        vrtc_resume(vm->vrtc);
        vatpit_resume(vm->vatpit);
        vhpet_resume(vm->vhpet);
        for (uint_t i = 0; i < vm->maxcpus; i++) {
                struct vcpu *vcpu = &vm->vcpu[i];

                if (!CPU_ISSET(i, &vm->active_cpus)) {
                        continue;
                }
                vlapic_resume(vcpu->vlapic);
        }

        return (0);
}

int
vm_map_mmio(struct vm *vm, vm_paddr_t gpa, size_t len, vm_paddr_t hpa)
{
        vm_object_t *obj;

        if ((obj = vmm_mmio_alloc(vm->vmspace, gpa, len, hpa)) == NULL)
                return (ENOMEM);
        else
                return (0);
}

int
vm_unmap_mmio(struct vm *vm, vm_paddr_t gpa, size_t len)
{
        return (vmspace_unmap(vm->vmspace, gpa, len));
}

/*
 * Return 'true' if 'gpa' is allocated in the guest address space.
 *
 * This function is called in the context of a running vcpu which acts as
 * an implicit lock on 'vm->mem_maps[]'.
 */
bool
vm_mem_allocated(struct vm *vm, int vcpuid, vm_paddr_t gpa)
{
        struct mem_map *mm;
        int i;

#ifdef INVARIANTS
        int hostcpu, state;
        state = vcpu_get_state(vm, vcpuid, &hostcpu);
        KASSERT(state == VCPU_RUNNING && hostcpu == curcpu,
            ("%s: invalid vcpu state %d/%d", __func__, state, hostcpu));
#endif

        for (i = 0; i < VM_MAX_MEMMAPS; i++) {
                mm = &vm->mem_maps[i];
                if (mm->len != 0 && gpa >= mm->gpa && gpa < mm->gpa + mm->len)
                        return (true);          /* 'gpa' is sysmem or devmem */
        }

        if (ppt_is_mmio(vm, gpa))
                return (true);                  /* 'gpa' is pci passthru mmio */

        return (false);
}

int
vm_alloc_memseg(struct vm *vm, int ident, size_t len, bool sysmem)
{
        struct mem_seg *seg;
        vm_object_t *obj;

        if (ident < 0 || ident >= VM_MAX_MEMSEGS)
                return (EINVAL);

        if (len == 0 || (len & PAGEOFFSET))
                return (EINVAL);

        seg = &vm->mem_segs[ident];
        if (seg->object != NULL) {
                if (seg->len == len && seg->sysmem == sysmem)
                        return (EEXIST);
                else
                        return (EINVAL);
        }

        obj = vm_object_mem_allocate(len, vm->mem_transient);
        if (obj == NULL)
                return (ENOMEM);

        seg->len = len;
        seg->object = obj;
        seg->sysmem = sysmem;
        return (0);
}

int
vm_get_memseg(struct vm *vm, int ident, size_t *len, bool *sysmem,
    vm_object_t **objptr)
{
        struct mem_seg *seg;

        if (ident < 0 || ident >= VM_MAX_MEMSEGS)
                return (EINVAL);

        seg = &vm->mem_segs[ident];
        if (len)
                *len = seg->len;
        if (sysmem)
                *sysmem = seg->sysmem;
        if (objptr)
                *objptr = seg->object;
        return (0);
}

void
vm_free_memseg(struct vm *vm, int ident)
{
        struct mem_seg *seg;

        KASSERT(ident >= 0 && ident < VM_MAX_MEMSEGS,
            ("%s: invalid memseg ident %d", __func__, ident));

        seg = &vm->mem_segs[ident];
        if (seg->object != NULL) {
                vm_object_release(seg->object);
                bzero(seg, sizeof (struct mem_seg));
        }
}

int
vm_mmap_memseg(struct vm *vm, vm_paddr_t gpa, int segid, uintptr_t off,
    size_t len, int prot, int flags)
{
        if (prot == 0 || (prot & ~(PROT_ALL)) != 0)
                return (EINVAL);

        if (flags & ~VM_MEMMAP_F_WIRED)
                return (EINVAL);

        if (segid < 0 || segid >= VM_MAX_MEMSEGS)
                return (EINVAL);
        const struct mem_seg *seg = &vm->mem_segs[segid];
        if (seg->object == NULL)
                return (EINVAL);

        const uintptr_t end = off + len;
        if (((gpa | off | end) & PAGEOFFSET) != 0)
                return (EINVAL);
        if (end < off || end > seg->len)
                return (EINVAL);

        struct mem_map *map = NULL;
        for (int i = 0; i < VM_MAX_MEMMAPS; i++) {
                struct mem_map *m = &vm->mem_maps[i];
                if (m->len == 0) {
                        map = m;
                        break;
                }
        }
        if (map == NULL)
                return (ENOSPC);

        int error = vmspace_map(vm->vmspace, seg->object, off, gpa, len, prot);
        if (error != 0)
                return (EFAULT);

        vm_object_reference(seg->object);

        if ((flags & VM_MEMMAP_F_WIRED) != 0) {
                error = vmspace_populate(vm->vmspace, gpa, len);
                if (error != 0) {
                        VERIFY0(vmspace_unmap(vm->vmspace, gpa, len));
                        return (EFAULT);
                }
        }

        map->gpa = gpa;
        map->len = len;
        map->segoff = off;
        map->segid = segid;
        map->prot = prot;
        map->flags = flags;
        return (0);
}

int
vm_munmap_memseg(struct vm *vm, vm_paddr_t gpa, size_t len)
{
        struct mem_map *m;
        int i;

        for (i = 0; i < VM_MAX_MEMMAPS; i++) {
                m = &vm->mem_maps[i];
                if (m->gpa == gpa && m->len == len &&
                    (m->flags & VM_MEMMAP_F_IOMMU) == 0) {
                        vm_free_memmap(vm, i);
                        return (0);
                }
        }

        return (EINVAL);
}

int
vm_mmap_getnext(struct vm *vm, vm_paddr_t *gpa, int *segid,
    uintptr_t *segoff, size_t *len, int *prot, int *flags)
{
        struct mem_map *mm, *mmnext;
        int i;

        mmnext = NULL;
        for (i = 0; i < VM_MAX_MEMMAPS; i++) {
                mm = &vm->mem_maps[i];
                if (mm->len == 0 || mm->gpa < *gpa)
                        continue;
                if (mmnext == NULL || mm->gpa < mmnext->gpa)
                        mmnext = mm;
        }

        if (mmnext != NULL) {
                *gpa = mmnext->gpa;
                if (segid)
                        *segid = mmnext->segid;
                if (segoff)
                        *segoff = mmnext->segoff;
                if (len)
                        *len = mmnext->len;
                if (prot)
                        *prot = mmnext->prot;
                if (flags)
                        *flags = mmnext->flags;
                return (0);
        } else {
                return (ENOENT);
        }
}

static void
vm_free_memmap(struct vm *vm, int ident)
{
        struct mem_map *mm;
        int error;

        mm = &vm->mem_maps[ident];
        if (mm->len) {
                error = vmspace_unmap(vm->vmspace, mm->gpa, mm->len);
                VERIFY0(error);
                bzero(mm, sizeof (struct mem_map));
        }
}

static __inline bool
sysmem_mapping(struct vm *vm, struct mem_map *mm)
{

        if (mm->len != 0 && vm->mem_segs[mm->segid].sysmem)
                return (true);
        else
                return (false);
}

vm_paddr_t
vmm_sysmem_maxaddr(struct vm *vm)
{
        struct mem_map *mm;
        vm_paddr_t maxaddr;
        int i;

        maxaddr = 0;
        for (i = 0; i < VM_MAX_MEMMAPS; i++) {
                mm = &vm->mem_maps[i];
                if (sysmem_mapping(vm, mm)) {
                        if (maxaddr < mm->gpa + mm->len)
                                maxaddr = mm->gpa + mm->len;
                }
        }
        return (maxaddr);
}

static void
vm_iommu_modify(struct vm *vm, bool map)
{
        int i, sz;
        vm_paddr_t gpa, hpa;
        struct mem_map *mm;
        vm_client_t *vmc;

        sz = PAGE_SIZE;
        vmc = vmspace_client_alloc(vm->vmspace);

        for (i = 0; i < VM_MAX_MEMMAPS; i++) {
                mm = &vm->mem_maps[i];
                if (!sysmem_mapping(vm, mm))
                        continue;

                if (map) {
                        KASSERT((mm->flags & VM_MEMMAP_F_IOMMU) == 0,
                            ("iommu map found invalid memmap %lx/%lx/%x",
                            mm->gpa, mm->len, mm->flags));
                        if ((mm->flags & VM_MEMMAP_F_WIRED) == 0)
                                continue;
                        mm->flags |= VM_MEMMAP_F_IOMMU;
                } else {
                        if ((mm->flags & VM_MEMMAP_F_IOMMU) == 0)
                                continue;
                        mm->flags &= ~VM_MEMMAP_F_IOMMU;
                        KASSERT((mm->flags & VM_MEMMAP_F_WIRED) != 0,
                            ("iommu unmap found invalid memmap %lx/%lx/%x",
                            mm->gpa, mm->len, mm->flags));
                }

                gpa = mm->gpa;
                while (gpa < mm->gpa + mm->len) {
                        vm_page_t *vmp;

                        vmp = vmc_hold(vmc, gpa, PROT_WRITE);
                        ASSERT(vmp != NULL);
                        hpa = ((uintptr_t)vmp_get_pfn(vmp) << PAGESHIFT);
                        (void) vmp_release(vmp);

                        /*
                         * When originally ported from FreeBSD, the logic for
                         * adding memory to the guest domain would
                         * simultaneously remove it from the host domain.  The
                         * justification for that is not clear, and FreeBSD has
                         * subsequently changed the behavior to not remove the
                         * memory from the host domain.
                         *
                         * Leaving the guest memory in the host domain for the
                         * life of the VM is necessary to make it available for
                         * DMA, such as through viona in the TX path.
                         */
                        if (map) {
                                iommu_create_mapping(vm->iommu, gpa, hpa, sz);
                        } else {
                                iommu_remove_mapping(vm->iommu, gpa, sz);
                        }

                        gpa += PAGE_SIZE;
                }
        }
        vmc_destroy(vmc);

        /*
         * Invalidate the cached translations associated with the domain
         * from which pages were removed.
         */
        iommu_invalidate_tlb(vm->iommu);
}

int
vm_unassign_pptdev(struct vm *vm, int pptfd)
{
        int error;

        error = ppt_unassign_device(vm, pptfd);
        if (error)
                return (error);

        if (ppt_assigned_devices(vm) == 0)
                vm_iommu_modify(vm, false);

        return (0);
}

int
vm_assign_pptdev(struct vm *vm, int pptfd)
{
        int error;
        vm_paddr_t maxaddr;

        /* Set up the IOMMU to do the 'gpa' to 'hpa' translation */
        if (ppt_assigned_devices(vm) == 0) {
                KASSERT(vm->iommu == NULL,
                    ("vm_assign_pptdev: iommu must be NULL"));
                maxaddr = vmm_sysmem_maxaddr(vm);
                vm->iommu = iommu_create_domain(maxaddr);
                if (vm->iommu == NULL)
                        return (ENXIO);
                vm_iommu_modify(vm, true);
        }

        error = ppt_assign_device(vm, pptfd);
        return (error);
}

int
vm_get_register(struct vm *vm, int vcpuid, int reg, uint64_t *retval)
{
        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        if (reg >= VM_REG_LAST)
                return (EINVAL);

        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        switch (reg) {
        case VM_REG_GUEST_XCR0:
                *retval = vcpu->guest_xcr0;
                return (0);
        default:
                return (VMGETREG(vm->cookie, vcpuid, reg, retval));
        }
}

int
vm_set_register(struct vm *vm, int vcpuid, int reg, uint64_t val)
{
        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        if (reg >= VM_REG_LAST)
                return (EINVAL);

        int error;
        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        switch (reg) {
        case VM_REG_GUEST_RIP:
                error = VMSETREG(vm->cookie, vcpuid, reg, val);
                if (error == 0) {
                        vcpu->nextrip = val;
                }
                return (error);
        case VM_REG_GUEST_XCR0:
                if (!validate_guest_xcr0(val, vmm_get_host_xcr0())) {
                        return (EINVAL);
                }
                vcpu->guest_xcr0 = val;
                return (0);
        default:
                return (VMSETREG(vm->cookie, vcpuid, reg, val));
        }
}

static bool
is_descriptor_table(int reg)
{
        switch (reg) {
        case VM_REG_GUEST_IDTR:
        case VM_REG_GUEST_GDTR:
                return (true);
        default:
                return (false);
        }
}

static bool
is_segment_register(int reg)
{
        switch (reg) {
        case VM_REG_GUEST_ES:
        case VM_REG_GUEST_CS:
        case VM_REG_GUEST_SS:
        case VM_REG_GUEST_DS:
        case VM_REG_GUEST_FS:
        case VM_REG_GUEST_GS:
        case VM_REG_GUEST_TR:
        case VM_REG_GUEST_LDTR:
                return (true);
        default:
                return (false);
        }
}

int
vm_get_seg_desc(struct vm *vm, int vcpu, int reg, struct seg_desc *desc)
{

        if (vcpu < 0 || vcpu >= vm->maxcpus)
                return (EINVAL);

        if (!is_segment_register(reg) && !is_descriptor_table(reg))
                return (EINVAL);

        return (VMGETDESC(vm->cookie, vcpu, reg, desc));
}

int
vm_set_seg_desc(struct vm *vm, int vcpu, int reg, const struct seg_desc *desc)
{
        if (vcpu < 0 || vcpu >= vm->maxcpus)
                return (EINVAL);

        if (!is_segment_register(reg) && !is_descriptor_table(reg))
                return (EINVAL);

        return (VMSETDESC(vm->cookie, vcpu, reg, desc));
}

static int
translate_hma_xsave_result(hma_fpu_xsave_result_t res)
{
        switch (res) {
        case HFXR_OK:
                return (0);
        case HFXR_NO_SPACE:
                return (ENOSPC);
        case HFXR_BAD_ALIGN:
        case HFXR_UNSUP_FMT:
        case HFXR_UNSUP_FEAT:
        case HFXR_INVALID_DATA:
                return (EINVAL);
        default:
                panic("unexpected xsave result");
        }
}

int
vm_get_fpu(struct vm *vm, int vcpuid, void *buf, size_t len)
{
        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        hma_fpu_xsave_result_t res;

        res = hma_fpu_get_xsave_state(vcpu->guestfpu, buf, len);
        return (translate_hma_xsave_result(res));
}

int
vm_set_fpu(struct vm *vm, int vcpuid, void *buf, size_t len)
{
        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        hma_fpu_xsave_result_t res;

        res = hma_fpu_set_xsave_state(vcpu->guestfpu, buf, len);
        return (translate_hma_xsave_result(res));
}

int
vm_get_run_state(struct vm *vm, int vcpuid, uint32_t *state, uint8_t *sipi_vec)
{
        struct vcpu *vcpu;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus) {
                return (EINVAL);
        }

        vcpu = &vm->vcpu[vcpuid];

        vcpu_lock(vcpu);
        *state = vcpu->run_state;
        *sipi_vec = vcpu->sipi_vector;
        vcpu_unlock(vcpu);

        return (0);
}

int
vm_set_run_state(struct vm *vm, int vcpuid, uint32_t state, uint8_t sipi_vec)
{
        struct vcpu *vcpu;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus) {
                return (EINVAL);
        }
        if (!VRS_IS_VALID(state)) {
                return (EINVAL);
        }

        vcpu = &vm->vcpu[vcpuid];

        vcpu_lock(vcpu);
        vcpu->run_state = state;
        vcpu->sipi_vector = sipi_vec;
        vcpu_notify_event_locked(vcpu, VCPU_NOTIFY_EXIT);
        vcpu_unlock(vcpu);

        return (0);
}

int
vm_track_dirty_pages(struct vm *vm, uint64_t gpa, size_t len, uint8_t *bitmap)
{
        ASSERT0(gpa & PAGEOFFSET);
        ASSERT0(len & PAGEOFFSET);

        /*
         * The only difference in expectations between this legacy interface and
         * an equivalent call to vm_npt_do_operation() is the check for
         * dirty-page-tracking being enabled on the vmspace.
         */
        if (!vmspace_get_tracking(vm->vmspace)) {
                return (EPERM);
        }

        vmspace_bits_operate(vm->vmspace, gpa, len,
            VBO_RESET_DIRTY | VBO_FLAG_BITMAP_OUT, bitmap);
        return (0);
}

int
vm_npt_do_operation(struct vm *vm, uint64_t gpa, size_t len, uint32_t oper,
    uint8_t *bitmap, int *rvalp)
{
        ASSERT0(gpa & PAGEOFFSET);
        ASSERT0(len & PAGEOFFSET);

        /*
         * For now, the bits defined in vmm_dev.h are meant to match up 1:1 with
         * those in vmm_vm.h
         */
        CTASSERT(VNO_OP_RESET_DIRTY == VBO_RESET_DIRTY);
        CTASSERT(VNO_OP_SET_DIRTY == VBO_SET_DIRTY);
        CTASSERT(VNO_OP_GET_DIRTY == VBO_GET_DIRTY);
        CTASSERT(VNO_FLAG_BITMAP_IN == VBO_FLAG_BITMAP_IN);
        CTASSERT(VNO_FLAG_BITMAP_OUT == VBO_FLAG_BITMAP_OUT);

        const uint32_t oper_only =
            oper & ~(VNO_FLAG_BITMAP_IN | VNO_FLAG_BITMAP_OUT);
        switch (oper_only) {
        case VNO_OP_RESET_DIRTY:
        case VNO_OP_SET_DIRTY:
        case VNO_OP_GET_DIRTY:
                if (len == 0) {
                        break;
                }
                vmspace_bits_operate(vm->vmspace, gpa, len, oper, bitmap);
                break;
        case VNO_OP_GET_TRACK_DIRTY:
                ASSERT3P(rvalp, !=, NULL);
                *rvalp = vmspace_get_tracking(vm->vmspace) ? 1 : 0;
                break;
        case VNO_OP_EN_TRACK_DIRTY:
                return (vmspace_set_tracking(vm->vmspace, true));
        case VNO_OP_DIS_TRACK_DIRTY:
                return (vmspace_set_tracking(vm->vmspace, false));
        default:
                return (EINVAL);
        }
        return (0);
}

static void
restore_guest_fpustate(struct vcpu *vcpu)
{
        /* Save host FPU and restore guest FPU */
        fpu_stop_emulating();
        hma_fpu_start_guest(vcpu->guestfpu);

        /* restore guest XCR0 if XSAVE is enabled in the host */
        if (rcr4() & CR4_XSAVE)
                load_xcr(0, vcpu->guest_xcr0);

        /*
         * The FPU is now "dirty" with the guest's state so turn on emulation
         * to trap any access to the FPU by the host.
         */
        fpu_start_emulating();
}

static void
save_guest_fpustate(struct vcpu *vcpu)
{

        if ((rcr0() & CR0_TS) == 0)
                panic("fpu emulation not enabled in host!");

        /* save guest XCR0 and restore host XCR0 */
        if (rcr4() & CR4_XSAVE) {
                vcpu->guest_xcr0 = rxcr(0);
                load_xcr(0, vmm_get_host_xcr0());
        }

        /* save guest FPU and restore host FPU */
        fpu_stop_emulating();
        hma_fpu_stop_guest(vcpu->guestfpu);
        /*
         * When the host state has been restored, we should not re-enable
         * CR0.TS on illumos for eager FPU.
         */
}

static int
vcpu_set_state_locked(struct vm *vm, int vcpuid, enum vcpu_state newstate,
    bool from_idle)
{
        struct vcpu *vcpu;
        int error;

        vcpu = &vm->vcpu[vcpuid];
        vcpu_assert_locked(vcpu);

        /*
         * State transitions from the vmmdev_ioctl() must always begin from
         * the VCPU_IDLE state. This guarantees that there is only a single
         * ioctl() operating on a vcpu at any point.
         */
        if (from_idle) {
                while (vcpu->state != VCPU_IDLE) {
                        vcpu->reqidle = true;
                        vcpu_notify_event_locked(vcpu, VCPU_NOTIFY_EXIT);
                        cv_wait(&vcpu->state_cv, &vcpu->lock);
                        vcpu->reqidle = false;
                }
        } else {
                KASSERT(vcpu->state != VCPU_IDLE, ("invalid transition from "
                    "vcpu idle state"));
        }

        if (vcpu->state == VCPU_RUNNING) {
                KASSERT(vcpu->hostcpu == curcpu, ("curcpu %d and hostcpu %d "
                    "mismatch for running vcpu", curcpu, vcpu->hostcpu));
        } else {
                KASSERT(vcpu->hostcpu == NOCPU, ("Invalid hostcpu %d for a "
                    "vcpu that is not running", vcpu->hostcpu));
        }

        /*
         * The following state transitions are allowed:
         * IDLE -> FROZEN -> IDLE
         * FROZEN -> RUNNING -> FROZEN
         * FROZEN -> SLEEPING -> FROZEN
         */
        switch (vcpu->state) {
        case VCPU_IDLE:
        case VCPU_RUNNING:
        case VCPU_SLEEPING:
                error = (newstate != VCPU_FROZEN);
                break;
        case VCPU_FROZEN:
                error = (newstate == VCPU_FROZEN);
                break;
        default:
                error = 1;
                break;
        }

        if (error)
                return (EBUSY);

        vcpu->state = newstate;
        if (newstate == VCPU_RUNNING)
                vcpu->hostcpu = curcpu;
        else
                vcpu->hostcpu = NOCPU;

        if (newstate == VCPU_IDLE) {
                cv_broadcast(&vcpu->state_cv);
        }

        return (0);
}

static void
vcpu_require_state(struct vm *vm, int vcpuid, enum vcpu_state newstate)
{
        int error;

        if ((error = vcpu_set_state(vm, vcpuid, newstate, false)) != 0)
                panic("Error %d setting state to %d\n", error, newstate);
}

static void
vcpu_require_state_locked(struct vm *vm, int vcpuid, enum vcpu_state newstate)
{
        int error;

        if ((error = vcpu_set_state_locked(vm, vcpuid, newstate, false)) != 0)
                panic("Error %d setting state to %d", error, newstate);
}

/*
 * Emulate a guest 'hlt' by sleeping until the vcpu is ready to run.
 */
static int
vm_handle_hlt(struct vm *vm, int vcpuid, bool intr_disabled)
{
        struct vcpu *vcpu;
        int vcpu_halted, vm_halted;
        bool userspace_exit = false;

        KASSERT(!CPU_ISSET(vcpuid, &vm->halted_cpus), ("vcpu already halted"));

        vcpu = &vm->vcpu[vcpuid];
        vcpu_halted = 0;
        vm_halted = 0;

        vcpu_lock(vcpu);
        while (1) {
                /*
                 * Do a final check for pending interrupts (including NMI and
                 * INIT) before putting this thread to sleep.
                 */
                if (vm_nmi_pending(vm, vcpuid))
                        break;
                if (vcpu_run_state_pending(vm, vcpuid))
                        break;
                if (!intr_disabled) {
                        if (vm_extint_pending(vm, vcpuid) ||
                            vlapic_pending_intr(vcpu->vlapic, NULL)) {
                                break;
                        }
                }

                /*
                 * Also check for software events which would cause a wake-up.
                 * This will set the appropriate exitcode directly, rather than
                 * requiring a trip through VM_RUN().
                 */
                if (vcpu_sleep_bailout_checks(vm, vcpuid)) {
                        userspace_exit = true;
                        break;
                }

                /*
                 * Some Linux guests implement "halt" by having all vcpus
                 * execute HLT with interrupts disabled. 'halted_cpus' keeps
                 * track of the vcpus that have entered this state. When all
                 * vcpus enter the halted state the virtual machine is halted.
                 */
                if (intr_disabled) {
                        if (!vcpu_halted && halt_detection_enabled) {
                                vcpu_halted = 1;
                                CPU_SET_ATOMIC(vcpuid, &vm->halted_cpus);
                        }
                        if (CPU_CMP(&vm->halted_cpus, &vm->active_cpus) == 0) {
                                vm_halted = 1;
                                break;
                        }
                }

                vcpu_ustate_change(vm, vcpuid, VU_IDLE);
                vcpu_require_state_locked(vm, vcpuid, VCPU_SLEEPING);
                (void) cv_wait_sig(&vcpu->vcpu_cv, &vcpu->lock);
                vcpu_require_state_locked(vm, vcpuid, VCPU_FROZEN);
                vcpu_ustate_change(vm, vcpuid, VU_EMU_KERN);
        }

        if (vcpu_halted)
                CPU_CLR_ATOMIC(vcpuid, &vm->halted_cpus);

        vcpu_unlock(vcpu);

        if (vm_halted) {
                (void) vm_suspend(vm, VM_SUSPEND_HALT, -1);
        }

        return (userspace_exit ? -1 : 0);
}

static int
vm_handle_paging(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        vm_client_t *vmc = vcpu->vmclient;
        struct vm_exit *vme = &vcpu->exitinfo;
        const int ftype = vme->u.paging.fault_type;

        ASSERT0(vme->inst_length);
        ASSERT(ftype == PROT_READ || ftype == PROT_WRITE || ftype == PROT_EXEC);

        if (vmc_fault(vmc, vme->u.paging.gpa, ftype) != 0) {
                /*
                 * If the fault cannot be serviced, kick it out to userspace for
                 * handling (or more likely, halting the instance).
                 */
                return (-1);
        }

        return (0);
}

int
vm_service_mmio_read(struct vm *vm, int cpuid, uint64_t gpa, uint64_t *rval,
    int rsize)
{
        int err = ESRCH;

        if (gpa >= DEFAULT_APIC_BASE && gpa < DEFAULT_APIC_BASE + PAGE_SIZE) {
                struct vlapic *vlapic = vm_lapic(vm, cpuid);

                err = vlapic_mmio_read(vlapic, gpa, rval, rsize);
        } else if (gpa >= VIOAPIC_BASE && gpa < VIOAPIC_BASE + VIOAPIC_SIZE) {
                err = vioapic_mmio_read(vm, cpuid, gpa, rval, rsize);
        } else if (gpa >= VHPET_BASE && gpa < VHPET_BASE + VHPET_SIZE) {
                err = vhpet_mmio_read(vm, cpuid, gpa, rval, rsize);
        } else if (vm->mmiohooks.mhc_count > 0) {
                for (uint_t i = 0; i < vm->mmiohooks.mhc_count; i++) {
                        mmiohook_entry_t *e = &vm->mmiohooks.mhc_entries[i];
                        const uint64_t end = e->mhe_addr + e->mhe_size;

                        if (gpa >= e->mhe_addr && gpa < end) {
                                err = e->mhe_func(e->mhe_arg, false, gpa, rsize,
                                    rval);
                                break;
                        }
                }
        }

        return (err);
}

int
vm_service_mmio_write(struct vm *vm, int cpuid, uint64_t gpa, uint64_t wval,
    int wsize)
{
        int err = ESRCH;

        if (gpa >= DEFAULT_APIC_BASE && gpa < DEFAULT_APIC_BASE + PAGE_SIZE) {
                struct vlapic *vlapic = vm_lapic(vm, cpuid);

                err = vlapic_mmio_write(vlapic, gpa, wval, wsize);
        } else if (gpa >= VIOAPIC_BASE && gpa < VIOAPIC_BASE + VIOAPIC_SIZE) {
                err = vioapic_mmio_write(vm, cpuid, gpa, wval, wsize);
        } else if (gpa >= VHPET_BASE && gpa < VHPET_BASE + VHPET_SIZE) {
                err = vhpet_mmio_write(vm, cpuid, gpa, wval, wsize);
        } else if (vm->mmiohooks.mhc_count > 0) {
                for (uint_t i = 0; i < vm->mmiohooks.mhc_count; i++) {
                        mmiohook_entry_t *e = &vm->mmiohooks.mhc_entries[i];
                        const uint64_t end = e->mhe_addr + e->mhe_size;

                        if (gpa >= e->mhe_addr && gpa < end) {
                                err = e->mhe_func(e->mhe_arg, true, gpa, wsize,
                                    &wval);
                                break;
                        }
                }
        }

        return (err);
}

static int
vm_handle_mmio_emul(struct vm *vm, int vcpuid)
{
        struct vie *vie;
        struct vcpu *vcpu;
        struct vm_exit *vme;
        uint64_t inst_addr;
        int error, fault, cs_d;

        vcpu = &vm->vcpu[vcpuid];
        vme = &vcpu->exitinfo;
        vie = vcpu->vie_ctx;

        KASSERT(vme->inst_length == 0, ("%s: invalid inst_length %d",
            __func__, vme->inst_length));

        inst_addr = vme->rip + vme->u.mmio_emul.cs_base;
        cs_d = vme->u.mmio_emul.cs_d;

        /* Fetch the faulting instruction */
        if (vie_needs_fetch(vie)) {
                error = vie_fetch_instruction(vie, vm, vcpuid, inst_addr,
                    &fault);
                if (error != 0) {
                        return (error);
                } else if (fault) {
                        /*
                         * If a fault during instruction fetch was encountered,
                         * it will have asserted that the appropriate exception
                         * be injected at next entry.
                         * No further work is required.
                         */
                        return (0);
                }
        }

        if (vie_decode_instruction(vie, vm, vcpuid, cs_d) != 0) {
                /* Dump (unrecognized) instruction bytes in userspace */
                vie_fallback_exitinfo(vie, vme);
                return (-1);
        }
        if (vme->u.mmio_emul.gla != VIE_INVALID_GLA &&
            vie_verify_gla(vie, vm, vcpuid, vme->u.mmio_emul.gla) != 0) {
                /* Decoded GLA does not match GLA from VM exit state */
                vie_fallback_exitinfo(vie, vme);
                return (-1);
        }

repeat:
        error = vie_emulate_mmio(vie, vm, vcpuid);
        if (error < 0) {
                /*
                 * MMIO not handled by any of the in-kernel-emulated devices, so
                 * make a trip out to userspace for it.
                 */
                vie_exitinfo(vie, vme);
        } else if (error == EAGAIN) {
                /*
                 * Continue emulating the rep-prefixed instruction, which has
                 * not completed its iterations.
                 *
                 * In case this can be emulated in-kernel and has a high
                 * repetition count (causing a tight spin), it should be
                 * deferential to yield conditions.
                 */
                if (!vcpu_should_yield(vm, vcpuid)) {
                        goto repeat;
                } else {
                        /*
                         * Defer to the contending load by making a trip to
                         * userspace with a no-op (BOGUS) exit reason.
                         */
                        vie_reset(vie);
                        vme->exitcode = VM_EXITCODE_BOGUS;
                        return (-1);
                }
        } else if (error == 0) {
                /* Update %rip now that instruction has been emulated */
                vie_advance_pc(vie, &vcpu->nextrip);
        }
        return (error);
}

static int
vm_handle_inout(struct vm *vm, int vcpuid, struct vm_exit *vme)
{
        struct vcpu *vcpu;
        struct vie *vie;
        int err;

        vcpu = &vm->vcpu[vcpuid];
        vie = vcpu->vie_ctx;

repeat:
        err = vie_emulate_inout(vie, vm, vcpuid);

        if (err < 0) {
                /*
                 * In/out not handled by any of the in-kernel-emulated devices,
                 * so make a trip out to userspace for it.
                 */
                vie_exitinfo(vie, vme);
                return (err);
        } else if (err == EAGAIN) {
                /*
                 * Continue emulating the rep-prefixed ins/outs, which has not
                 * completed its iterations.
                 *
                 * In case this can be emulated in-kernel and has a high
                 * repetition count (causing a tight spin), it should be
                 * deferential to yield conditions.
                 */
                if (!vcpu_should_yield(vm, vcpuid)) {
                        goto repeat;
                } else {
                        /*
                         * Defer to the contending load by making a trip to
                         * userspace with a no-op (BOGUS) exit reason.
                         */
                        vie_reset(vie);
                        vme->exitcode = VM_EXITCODE_BOGUS;
                        return (-1);
                }
        } else if (err != 0) {
                /* Emulation failure.  Bail all the way out to userspace. */
                vme->exitcode = VM_EXITCODE_INST_EMUL;
                bzero(&vme->u.inst_emul, sizeof (vme->u.inst_emul));
                return (-1);
        }

        vie_advance_pc(vie, &vcpu->nextrip);
        return (0);
}

static int
vm_handle_inst_emul(struct vm *vm, int vcpuid)
{
        struct vie *vie;
        struct vcpu *vcpu;
        struct vm_exit *vme;
        uint64_t cs_base;
        int error, fault, cs_d;

        vcpu = &vm->vcpu[vcpuid];
        vme = &vcpu->exitinfo;
        vie = vcpu->vie_ctx;

        vie_cs_info(vie, vm, vcpuid, &cs_base, &cs_d);

        /* Fetch the faulting instruction */
        ASSERT(vie_needs_fetch(vie));
        error = vie_fetch_instruction(vie, vm, vcpuid, vme->rip + cs_base,
            &fault);
        if (error != 0) {
                return (error);
        } else if (fault) {
                /*
                 * If a fault during instruction fetch was encounted, it will
                 * have asserted that the appropriate exception be injected at
                 * next entry.  No further work is required.
                 */
                return (0);
        }

        if (vie_decode_instruction(vie, vm, vcpuid, cs_d) != 0) {
                /* Dump (unrecognized) instruction bytes in userspace */
                vie_fallback_exitinfo(vie, vme);
                return (-1);
        }

        error = vie_emulate_other(vie, vm, vcpuid);
        if (error != 0) {
                /*
                 * Instruction emulation was unable to complete successfully, so
                 * kick it out to userspace for handling.
                 */
                vie_fallback_exitinfo(vie, vme);
        } else {
                /* Update %rip now that instruction has been emulated */
                vie_advance_pc(vie, &vcpu->nextrip);
        }
        return (error);
}

static int
vm_handle_run_state(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        bool handled = false;

        vcpu_lock(vcpu);
        while (1) {
                if ((vcpu->run_state & VRS_PEND_INIT) != 0) {
                        vcpu_unlock(vcpu);
                        VERIFY0(vcpu_arch_reset(vm, vcpuid, true));
                        vcpu_lock(vcpu);

                        vcpu->run_state &= ~(VRS_RUN | VRS_PEND_INIT);
                        vcpu->run_state |= VRS_INIT;
                }

                if ((vcpu->run_state & (VRS_INIT | VRS_RUN | VRS_PEND_SIPI)) ==
                    (VRS_INIT | VRS_PEND_SIPI)) {
                        const uint8_t vector = vcpu->sipi_vector;

                        vcpu_unlock(vcpu);
                        VERIFY0(vcpu_vector_sipi(vm, vcpuid, vector));
                        vcpu_lock(vcpu);

                        vcpu->run_state &= ~VRS_PEND_SIPI;
                        vcpu->run_state |= VRS_RUN;
                }

                /*
                 * If the vCPU is now in the running state, there is no need to
                 * wait for anything prior to re-entry.
                 */
                if ((vcpu->run_state & VRS_RUN) != 0) {
                        handled = true;
                        break;
                }

                /*
                 * Also check for software events which would cause a wake-up.
                 * This will set the appropriate exitcode directly, rather than
                 * requiring a trip through VM_RUN().
                 */
                if (vcpu_sleep_bailout_checks(vm, vcpuid)) {
                        break;
                }

                vcpu_ustate_change(vm, vcpuid, VU_IDLE);
                vcpu_require_state_locked(vm, vcpuid, VCPU_SLEEPING);
                (void) cv_wait_sig(&vcpu->vcpu_cv, &vcpu->lock);
                vcpu_require_state_locked(vm, vcpuid, VCPU_FROZEN);
                vcpu_ustate_change(vm, vcpuid, VU_EMU_KERN);
        }
        vcpu_unlock(vcpu);

        return (handled ? 0 : -1);
}

static int
vm_rdmtrr(const struct vm_mtrr *mtrr, uint32_t num, uint64_t *val)
{
        switch (num) {
        case MSR_MTRRcap:
                *val = MTRR_CAP_WC | MTRR_CAP_FIXED | VMM_MTRR_VAR_MAX;
                break;
        case MSR_MTRRdefType:
                *val = mtrr->def_type;
                break;
        case MSR_MTRR4kBase ... MSR_MTRR4kBase + 7:
                *val = mtrr->fixed4k[num - MSR_MTRR4kBase];
                break;
        case MSR_MTRR16kBase ... MSR_MTRR16kBase + 1:
                *val = mtrr->fixed16k[num - MSR_MTRR16kBase];
                break;
        case MSR_MTRR64kBase:
                *val = mtrr->fixed64k;
                break;
        case MSR_MTRRVarBase ... MSR_MTRRVarBase + (VMM_MTRR_VAR_MAX * 2) - 1: {
                uint_t offset = num - MSR_MTRRVarBase;
                if (offset % 2 == 0) {
                        *val = mtrr->var[offset / 2].base;
                } else {
                        *val = mtrr->var[offset / 2].mask;
                }
                break;
        }
        default:
                return (EINVAL);
        }

        return (0);
}

static int
vm_wrmtrr(struct vm_mtrr *mtrr, uint32_t num, uint64_t val)
{
        switch (num) {
        case MSR_MTRRcap:
                /* MTRRCAP is read only */
                return (EPERM);
        case MSR_MTRRdefType:
                if (val & ~VMM_MTRR_DEF_MASK) {
                        /* generate #GP on writes to reserved fields */
                        return (EINVAL);
                }
                mtrr->def_type = val;
                break;
        case MSR_MTRR4kBase ... MSR_MTRR4kBase + 7:
                mtrr->fixed4k[num - MSR_MTRR4kBase] = val;
                break;
        case MSR_MTRR16kBase ... MSR_MTRR16kBase + 1:
                mtrr->fixed16k[num - MSR_MTRR16kBase] = val;
                break;
        case MSR_MTRR64kBase:
                mtrr->fixed64k = val;
                break;
        case MSR_MTRRVarBase ... MSR_MTRRVarBase + (VMM_MTRR_VAR_MAX * 2) - 1: {
                uint_t offset = num - MSR_MTRRVarBase;
                if (offset % 2 == 0) {
                        if (val & ~VMM_MTRR_PHYSBASE_MASK) {
                                /* generate #GP on writes to reserved fields */
                                return (EINVAL);
                        }
                        mtrr->var[offset / 2].base = val;
                } else {
                        if (val & ~VMM_MTRR_PHYSMASK_MASK) {
                                /* generate #GP on writes to reserved fields */
                                return (EINVAL);
                        }
                        mtrr->var[offset / 2].mask = val;
                }
                break;
        }
        default:
                return (EINVAL);
        }

        return (0);
}

static bool
is_mtrr_msr(uint32_t msr)
{
        switch (msr) {
        case MSR_MTRRcap:
        case MSR_MTRRdefType:
        case MSR_MTRR4kBase ... MSR_MTRR4kBase + 7:
        case MSR_MTRR16kBase ... MSR_MTRR16kBase + 1:
        case MSR_MTRR64kBase:
        case MSR_MTRRVarBase ... MSR_MTRRVarBase + (VMM_MTRR_VAR_MAX * 2) - 1:
                return (true);
        default:
                return (false);
        }
}

static int
vm_handle_rdmsr(struct vm *vm, int vcpuid, struct vm_exit *vme)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        const uint32_t code = vme->u.msr.code;
        uint64_t val = 0;

        switch (code) {
        case MSR_MCG_CAP:
        case MSR_MCG_STATUS:
                val = 0;
                break;

        case MSR_MTRRcap:
        case MSR_MTRRdefType:
        case MSR_MTRR4kBase ... MSR_MTRR4kBase + 7:
        case MSR_MTRR16kBase ... MSR_MTRR16kBase + 1:
        case MSR_MTRR64kBase:
        case MSR_MTRRVarBase ... MSR_MTRRVarBase + (VMM_MTRR_VAR_MAX * 2) - 1:
                if (vm_rdmtrr(&vcpu->mtrr, code, &val) != 0)
                        vm_inject_gp(vm, vcpuid);
                break;

        case MSR_TSC:
                /*
                 * Get the guest TSC, applying necessary vCPU offsets.
                 *
                 * In all likelihood, this should always be handled in guest
                 * context by VMX/SVM rather than taking an exit.  (Both VMX and
                 * SVM pass through read-only access to MSR_TSC to the guest.)
                 *
                 * The VM-wide TSC offset and per-vCPU offset are included in
                 * the calculations of vcpu_tsc_offset(), so this is sufficient
                 * to use as the offset in our calculations.
                 *
                 * No physical offset is requested of vcpu_tsc_offset() since
                 * rdtsc_offset() takes care of that instead.
                 */
                val = calc_guest_tsc(rdtsc_offset(), vm->freq_multiplier,
                    vcpu_tsc_offset(vm, vcpuid, false));
                break;

        default:
                /*
                 * Anything not handled at this point will be kicked out to
                 * userspace for attempted processing there.
                 */
                return (-1);
        }

        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_RAX,
            val & 0xffffffff));
        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_RDX,
            val >> 32));
        return (0);
}

static int
vm_handle_wrmsr(struct vm *vm, int vcpuid, struct vm_exit *vme)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        const uint32_t code = vme->u.msr.code;
        const uint64_t val = vme->u.msr.wval;

        switch (code) {
        case MSR_MCG_CAP:
        case MSR_MCG_STATUS:
                /* Ignore writes */
                break;

        case MSR_MTRRcap:
        case MSR_MTRRdefType:
        case MSR_MTRR4kBase ... MSR_MTRR4kBase + 7:
        case MSR_MTRR16kBase ... MSR_MTRR16kBase + 1:
        case MSR_MTRR64kBase:
        case MSR_MTRRVarBase ... MSR_MTRRVarBase + (VMM_MTRR_VAR_MAX * 2) - 1:
                if (vm_wrmtrr(&vcpu->mtrr, code, val) != 0)
                        vm_inject_gp(vm, vcpuid);
                break;

        case MSR_TSC:
                /*
                 * The effect of writing the TSC MSR is that a subsequent read
                 * of the TSC would report that value written (plus any time
                 * elapsed between the write and the read).
                 *
                 * To calculate that per-vCPU offset, we can work backwards from
                 * the guest TSC at the time of write:
                 *
                 * value = current guest TSC + vCPU offset
                 *
                 * so therefore:
                 *
                 * value - current guest TSC = vCPU offset
                 */
                vcpu->tsc_offset = val - calc_guest_tsc(rdtsc_offset(),
                    vm->freq_multiplier, vm->tsc_offset);
                break;

        default:
                /*
                 * Anything not handled at this point will be kicked out to
                 * userspace for attempted processing there.
                 */
                return (-1);
        }

        return (0);
}

/*
 * Has a suspend event been asserted on the VM?
 *
 * The reason and (in the case of a triple-fault) source vcpuid are optionally
 * returned if such a state is present.
 */
static bool
vm_is_suspended(struct vm *vm, struct vm_exit *vme)
{
        const int val = vm->suspend_how;
        if (val == 0) {
                return (false);
        } else {
                if (vme != NULL) {
                        vme->exitcode = VM_EXITCODE_SUSPENDED;
                        vme->u.suspended.how = val;
                        vme->u.suspended.source = vm->suspend_source;
                        /*
                         * Normalize suspend event time and, on the off chance
                         * that it was recorded as occuring prior to VM boot,
                         * clamp it to a minimum of 0.
                         */
                        vme->u.suspended.when = (uint64_t)
                            MAX(vm_normalize_hrtime(vm, vm->suspend_when), 0);
                }
                return (true);
        }
}

int
vm_suspend(struct vm *vm, enum vm_suspend_how how, int source)
{
        if (how <= VM_SUSPEND_NONE || how >= VM_SUSPEND_LAST) {
                return (EINVAL);
        }

        /*
         * Although the common case of calling vm_suspend() is via
         * ioctl(VM_SUSPEND), where all the vCPUs will be held in the frozen
         * state, it can also be called by a running vCPU to indicate a
         * triple-fault.  In the latter case, there is no exclusion from a
         * racing vm_suspend() from a different vCPU, so assertion of the
         * suspended state must be performed carefully.
         *
         * The `suspend_when` is set first via atomic cmpset to pick a "winner"
         * of the suspension race, followed by population of 'suspend_source'.
         * Only after those are done, and a membar is emitted will 'suspend_how'
         * be set, which makes the suspended state visible to any vCPU checking
         * for it.  That order will prevent an incomplete suspend state (between
         * 'how', 'source', and 'when') from being observed.
         */
        const hrtime_t now = gethrtime();
        if (atomic_cmpset_long((ulong_t *)&vm->suspend_when, 0, now) == 0) {
                return (EALREADY);
        }
        vm->suspend_source = source;
        membar_producer();
        vm->suspend_how = how;

        /* Notify all active vcpus that they are now suspended. */
        for (uint_t i = 0; i < vm->maxcpus; i++) {
                struct vcpu *vcpu = &vm->vcpu[i];

                vcpu_lock(vcpu);

                if (!CPU_ISSET(i, &vm->active_cpus)) {
                        /*
                         * vCPUs not already marked as active can be ignored,
                         * since they cannot become marked as active unless the
                         * VM is reinitialized, clearing the suspended state.
                         */
                        vcpu_unlock(vcpu);
                        continue;
                }

                switch (vcpu->state) {
                case VCPU_IDLE:
                case VCPU_FROZEN:
                        /*
                         * vCPUs not locked by in-kernel activity can be
                         * immediately marked as suspended: The ustate is moved
                         * back to VU_INIT, since no further guest work will
                         * occur while the VM is in this state.
                         *
                         * A FROZEN vCPU may still change its ustate on the way
                         * out of the kernel, but a subsequent check at the end
                         * of vm_run() should be adequate to fix it up.
                         */
                        vcpu_ustate_change(vm, i, VU_INIT);
                        break;
                default:
                        /*
                         * Any vCPUs which are running or waiting in-kernel
                         * (such as in HLT) are notified to pick up the newly
                         * suspended state.
                         */
                        vcpu_notify_event_locked(vcpu, VCPU_NOTIFY_EXIT);
                        break;
                }
                vcpu_unlock(vcpu);
        }
        return (0);
}

void
vm_exit_run_state(struct vm *vm, int vcpuid, uint64_t rip)
{
        struct vm_exit *vmexit;

        vmexit = vm_exitinfo(vm, vcpuid);
        vmexit->rip = rip;
        vmexit->inst_length = 0;
        vmexit->exitcode = VM_EXITCODE_RUN_STATE;
        vmm_stat_incr(vm, vcpuid, VMEXIT_RUN_STATE, 1);
}

/*
 * Some vmm resources, such as the lapic, may have CPU-specific resources
 * allocated to them which would benefit from migration onto the host CPU which
 * is processing the vcpu state.
 */
static void
vm_localize_resources(struct vm *vm, struct vcpu *vcpu)
{
        /*
         * Localizing cyclic resources requires acquisition of cpu_lock, and
         * doing so with kpreempt disabled is a recipe for deadlock disaster.
         */
        VERIFY(curthread->t_preempt == 0);

        /*
         * Do not bother with localization if this vCPU is about to return to
         * the host CPU it was last localized to.
         */
        if (vcpu->lastloccpu == curcpu)
                return;

        /*
         * Localize system-wide resources to the primary boot vCPU.  While any
         * of the other vCPUs may access them, it keeps the potential interrupt
         * footprint constrained to CPUs involved with this instance.
         */
        if (vcpu == &vm->vcpu[0]) {
                vhpet_localize_resources(vm->vhpet);
                vrtc_localize_resources(vm->vrtc);
                vatpit_localize_resources(vm->vatpit);
        }

        vlapic_localize_resources(vcpu->vlapic);

        vcpu->lastloccpu = curcpu;
}

static void
vmm_savectx(void *arg)
{
        vm_thread_ctx_t *vtc = arg;
        struct vm *vm = vtc->vtc_vm;
        const int vcpuid = vtc->vtc_vcpuid;

        if (ops->vmsavectx != NULL) {
                ops->vmsavectx(vm->cookie, vcpuid);
        }

        /*
         * Account for going off-cpu, unless the vCPU is idled, where being
         * off-cpu is the explicit point.
         */
        if (vm->vcpu[vcpuid].ustate != VU_IDLE) {
                vtc->vtc_ustate = vm->vcpu[vcpuid].ustate;
                vcpu_ustate_change(vm, vcpuid, VU_SCHED);
        }

        /*
         * If the CPU holds the restored guest FPU state, save it and restore
         * the host FPU state before this thread goes off-cpu.
         */
        if ((vtc->vtc_status & VTCS_FPU_RESTORED) != 0) {
                struct vcpu *vcpu = &vm->vcpu[vcpuid];

                save_guest_fpustate(vcpu);
                vtc->vtc_status &= ~VTCS_FPU_RESTORED;
        }
}

static void
vmm_restorectx(void *arg)
{
        vm_thread_ctx_t *vtc = arg;
        struct vm *vm = vtc->vtc_vm;
        const int vcpuid = vtc->vtc_vcpuid;

        /* Complete microstate accounting for vCPU being off-cpu */
        if (vm->vcpu[vcpuid].ustate != VU_IDLE) {
                vcpu_ustate_change(vm, vcpuid, vtc->vtc_ustate);
        }

        /*
         * When coming back on-cpu, only restore the guest FPU status if the
         * thread is in a context marked as requiring it.  This should be rare,
         * occurring only when a future logic error results in a voluntary
         * sleep during the VMRUN critical section.
         *
         * The common case will result in elision of the guest FPU state
         * restoration, deferring that action until it is clearly necessary
         * during vm_run.
         */
        VERIFY((vtc->vtc_status & VTCS_FPU_RESTORED) == 0);
        if ((vtc->vtc_status & VTCS_FPU_CTX_CRITICAL) != 0) {
                struct vcpu *vcpu = &vm->vcpu[vcpuid];

                restore_guest_fpustate(vcpu);
                vtc->vtc_status |= VTCS_FPU_RESTORED;
        }

        if (ops->vmrestorectx != NULL) {
                ops->vmrestorectx(vm->cookie, vcpuid);
        }

}

/* Convenience defines for parsing vm_entry`cmd values */
#define VEC_MASK_FLAGS  (VEC_FLAG_EXIT_CONSISTENT)
#define VEC_MASK_CMD    (~VEC_MASK_FLAGS)

static int
vm_entry_actions(struct vm *vm, int vcpuid, const struct vm_entry *entry,
    struct vm_exit *vme)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        struct vie *vie = vcpu->vie_ctx;
        int err = 0;

        const uint_t cmd = entry->cmd & VEC_MASK_CMD;
        const uint_t flags = entry->cmd & VEC_MASK_FLAGS;

        switch (cmd) {
        case VEC_DEFAULT:
                break;
        case VEC_DISCARD_INSTR:
                vie_reset(vie);
                break;
        case VEC_FULFILL_MMIO:
                err = vie_fulfill_mmio(vie, &entry->u.mmio);
                if (err == 0) {
                        err = vie_emulate_mmio(vie, vm, vcpuid);
                        if (err == 0) {
                                vie_advance_pc(vie, &vcpu->nextrip);
                        } else if (err < 0) {
                                vie_exitinfo(vie, vme);
                        } else if (err == EAGAIN) {
                                /*
                                 * Clear the instruction emulation state in
                                 * order to re-enter VM context and continue
                                 * this 'rep <instruction>'
                                 */
                                vie_reset(vie);
                                err = 0;
                        }
                }
                break;
        case VEC_FULFILL_INOUT:
                err = vie_fulfill_inout(vie, &entry->u.inout);
                if (err == 0) {
                        err = vie_emulate_inout(vie, vm, vcpuid);
                        if (err == 0) {
                                vie_advance_pc(vie, &vcpu->nextrip);
                        } else if (err < 0) {
                                vie_exitinfo(vie, vme);
                        } else if (err == EAGAIN) {
                                /*
                                 * Clear the instruction emulation state in
                                 * order to re-enter VM context and continue
                                 * this 'rep ins/outs'
                                 */
                                vie_reset(vie);
                                err = 0;
                        }
                }
                break;
        default:
                return (EINVAL);
        }

        /*
         * Pay heed to requests for exit-when-vCPU-is-consistent requests, at
         * least when we are not immediately bound for another exit due to
         * multi-part instruction emulation or related causes.
         */
        if ((flags & VEC_FLAG_EXIT_CONSISTENT) != 0 && err == 0) {
                vcpu->reqconsist = true;
        }

        return (err);
}

static int
vm_loop_checks(struct vm *vm, int vcpuid, struct vm_exit *vme)
{
        struct vie *vie;

        vie = vm->vcpu[vcpuid].vie_ctx;

        if (vie_pending(vie)) {
                /*
                 * Userspace has not fulfilled the pending needs of the
                 * instruction emulation, so bail back out.
                 */
                vie_exitinfo(vie, vme);
                return (-1);
        }

        return (0);
}

int
vm_run(struct vm *vm, int vcpuid, const struct vm_entry *entry)
{
        int error;
        struct vcpu *vcpu;
        struct vm_exit *vme;
        bool intr_disabled;
        int affinity_type = CPU_CURRENT;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);
        if (!CPU_ISSET(vcpuid, &vm->active_cpus))
                return (EINVAL);
        if (vm->is_paused) {
                return (EBUSY);
        }

        vcpu = &vm->vcpu[vcpuid];
        vme = &vcpu->exitinfo;

        vcpu_ustate_change(vm, vcpuid, VU_EMU_KERN);

        vcpu->vtc.vtc_status = 0;
        ctxop_attach(curthread, vcpu->ctxop);

        error = vm_entry_actions(vm, vcpuid, entry, vme);
        if (error != 0) {
                goto exit;
        }

restart:
        error = vm_loop_checks(vm, vcpuid, vme);
        if (error != 0) {
                goto exit;
        }

        thread_affinity_set(curthread, affinity_type);
        /*
         * Resource localization should happen after the CPU affinity for the
         * thread has been set to ensure that access from restricted contexts,
         * such as VMX-accelerated APIC operations, can occur without inducing
         * cyclic cross-calls.
         *
         * This must be done prior to disabling kpreempt via critical_enter().
         */
        vm_localize_resources(vm, vcpu);
        affinity_type = CPU_CURRENT;
        critical_enter();

        /* Force a trip through update_sregs to reload %fs/%gs and friends */
        PCB_SET_UPDATE_SEGS(&ttolwp(curthread)->lwp_pcb);

        if ((vcpu->vtc.vtc_status & VTCS_FPU_RESTORED) == 0) {
                restore_guest_fpustate(vcpu);
                vcpu->vtc.vtc_status |= VTCS_FPU_RESTORED;
        }
        vcpu->vtc.vtc_status |= VTCS_FPU_CTX_CRITICAL;

        vcpu_require_state(vm, vcpuid, VCPU_RUNNING);
        error = VMRUN(vm->cookie, vcpuid, vcpu->nextrip);
        vcpu_require_state(vm, vcpuid, VCPU_FROZEN);

        /*
         * Once clear of the delicate contexts comprising the VM_RUN handler,
         * thread CPU affinity can be loosened while other processing occurs.
         */
        vcpu->vtc.vtc_status &= ~VTCS_FPU_CTX_CRITICAL;
        thread_affinity_clear(curthread);
        critical_exit();

        if (error != 0) {
                /* Communicate out any error from VMRUN() above */
                goto exit;
        }

        vcpu->nextrip = vme->rip + vme->inst_length;
        switch (vme->exitcode) {
        case VM_EXITCODE_RUN_STATE:
                error = vm_handle_run_state(vm, vcpuid);
                break;
        case VM_EXITCODE_IOAPIC_EOI:
                vioapic_process_eoi(vm, vcpuid,
                    vme->u.ioapic_eoi.vector);
                break;
        case VM_EXITCODE_HLT:
                intr_disabled = ((vme->u.hlt.rflags & PSL_I) == 0);
                error = vm_handle_hlt(vm, vcpuid, intr_disabled);
                break;
        case VM_EXITCODE_PAGING:
                error = vm_handle_paging(vm, vcpuid);
                break;
        case VM_EXITCODE_MMIO_EMUL:
                error = vm_handle_mmio_emul(vm, vcpuid);
                break;
        case VM_EXITCODE_INOUT:
                error = vm_handle_inout(vm, vcpuid, vme);
                break;
        case VM_EXITCODE_INST_EMUL:
                error = vm_handle_inst_emul(vm, vcpuid);
                break;
        case VM_EXITCODE_MONITOR:
        case VM_EXITCODE_MWAIT:
        case VM_EXITCODE_VMINSN:
                vm_inject_ud(vm, vcpuid);
                break;
        case VM_EXITCODE_RDMSR:
                error = vm_handle_rdmsr(vm, vcpuid, vme);
                break;
        case VM_EXITCODE_WRMSR:
                error = vm_handle_wrmsr(vm, vcpuid, vme);
                break;
        case VM_EXITCODE_HT:
                affinity_type = CPU_BEST;
                break;
        case VM_EXITCODE_MTRAP:
                VERIFY0(vm_suspend_cpu(vm, vcpuid));
                error = -1;
                break;
        default:
                /* handled in userland */
                error = -1;
                break;
        }

        if (error == 0) {
                /* VM exit conditions handled in-kernel, continue running */
                goto restart;
        }

exit:
        kpreempt_disable();
        ctxop_detach(curthread, vcpu->ctxop);
        /* Make sure all of the needed vCPU context state is saved */
        vmm_savectx(&vcpu->vtc);
        kpreempt_enable();

        /*
         * Bill time in userspace against VU_EMU_USER, unless the VM is
         * suspended, in which case VU_INIT is the choice.
         */
        vcpu_ustate_change(vm, vcpuid,
            vm_is_suspended(vm, NULL) ? VU_INIT : VU_EMU_USER);

        return (error);
}

int
vm_restart_instruction(void *arg, int vcpuid)
{
        struct vm *vm;
        struct vcpu *vcpu;
        enum vcpu_state state;
        uint64_t rip;
        int error;

        vm = arg;
        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        vcpu = &vm->vcpu[vcpuid];
        state = vcpu_get_state(vm, vcpuid, NULL);
        if (state == VCPU_RUNNING) {
                /*
                 * When a vcpu is "running" the next instruction is determined
                 * by adding 'rip' and 'inst_length' in the vcpu's 'exitinfo'.
                 * Thus setting 'inst_length' to zero will cause the current
                 * instruction to be restarted.
                 */
                vcpu->exitinfo.inst_length = 0;
        } else if (state == VCPU_FROZEN) {
                /*
                 * When a vcpu is "frozen" it is outside the critical section
                 * around VMRUN() and 'nextrip' points to the next instruction.
                 * Thus instruction restart is achieved by setting 'nextrip'
                 * to the vcpu's %rip.
                 */
                error = vm_get_register(vm, vcpuid, VM_REG_GUEST_RIP, &rip);
                KASSERT(!error, ("%s: error %d getting rip", __func__, error));
                vcpu->nextrip = rip;
        } else {
                panic("%s: invalid state %d", __func__, state);
        }
        return (0);
}

int
vm_exit_intinfo(struct vm *vm, int vcpuid, uint64_t info)
{
        struct vcpu *vcpu;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        vcpu = &vm->vcpu[vcpuid];

        if (VM_INTINFO_PENDING(info)) {
                const uint32_t type = VM_INTINFO_TYPE(info);
                const uint8_t vector = VM_INTINFO_VECTOR(info);

                if (type == VM_INTINFO_NMI && vector != IDT_NMI)
                        return (EINVAL);
                if (type == VM_INTINFO_HWEXCP && vector >= 32)
                        return (EINVAL);
                if (info & VM_INTINFO_MASK_RSVD)
                        return (EINVAL);
        } else {
                info = 0;
        }
        vcpu->exit_intinfo = info;
        return (0);
}

enum exc_class {
        EXC_BENIGN,
        EXC_CONTRIBUTORY,
        EXC_PAGEFAULT
};

#define IDT_VE  20      /* Virtualization Exception (Intel specific) */

static enum exc_class
exception_class(uint64_t info)
{
        ASSERT(VM_INTINFO_PENDING(info));

        /* Table 6-4, "Interrupt and Exception Classes", Intel SDM, Vol 3 */
        switch (VM_INTINFO_TYPE(info)) {
        case VM_INTINFO_HWINTR:
        case VM_INTINFO_SWINTR:
        case VM_INTINFO_NMI:
                return (EXC_BENIGN);
        default:
                /*
                 * Hardware exception.
                 *
                 * SVM and VT-x use identical type values to represent NMI,
                 * hardware interrupt and software interrupt.
                 *
                 * SVM uses type '3' for all exceptions. VT-x uses type '3'
                 * for exceptions except #BP and #OF. #BP and #OF use a type
                 * value of '5' or '6'. Therefore we don't check for explicit
                 * values of 'type' to classify 'intinfo' into a hardware
                 * exception.
                 */
                break;
        }

        switch (VM_INTINFO_VECTOR(info)) {
        case IDT_PF:
        case IDT_VE:
                return (EXC_PAGEFAULT);
        case IDT_DE:
        case IDT_TS:
        case IDT_NP:
        case IDT_SS:
        case IDT_GP:
                return (EXC_CONTRIBUTORY);
        default:
                return (EXC_BENIGN);
        }
}

/*
 * Fetch event pending injection into the guest, if one exists.
 *
 * Returns true if an event is to be injected (which is placed in `retinfo`).
 */
bool
vm_entry_intinfo(struct vm *vm, int vcpuid, uint64_t *retinfo)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        const uint64_t info1 = vcpu->exit_intinfo;
        vcpu->exit_intinfo = 0;
        const uint64_t info2 = vcpu->exc_pending;
        vcpu->exc_pending = 0;

        if (VM_INTINFO_PENDING(info1) && VM_INTINFO_PENDING(info2)) {
                /*
                 * If an exception occurs while attempting to call the
                 * double-fault handler the processor enters shutdown mode
                 * (aka triple fault).
                 */
                if (VM_INTINFO_TYPE(info1) == VM_INTINFO_HWEXCP &&
                    VM_INTINFO_VECTOR(info1) == IDT_DF) {
                        (void) vm_suspend(vm, VM_SUSPEND_TRIPLEFAULT, vcpuid);
                        *retinfo = 0;
                        return (false);
                }
                /*
                 * "Conditions for Generating a Double Fault"
                 *  Intel SDM, Vol3, Table 6-5
                 */
                const enum exc_class exc1 = exception_class(info1);
                const enum exc_class exc2 = exception_class(info2);
                if ((exc1 == EXC_CONTRIBUTORY && exc2 == EXC_CONTRIBUTORY) ||
                    (exc1 == EXC_PAGEFAULT && exc2 != EXC_BENIGN)) {
                        /* Convert nested fault into a double fault. */
                        *retinfo =
                            VM_INTINFO_VALID |
                            VM_INTINFO_DEL_ERRCODE |
                            VM_INTINFO_HWEXCP |
                            IDT_DF;
                } else {
                        /* Handle exceptions serially */
                        vcpu->exit_intinfo = info1;
                        *retinfo = info2;
                }
                return (true);
        } else if (VM_INTINFO_PENDING(info1)) {
                *retinfo = info1;
                return (true);
        } else if (VM_INTINFO_PENDING(info2)) {
                *retinfo = info2;
                return (true);
        }

        return (false);
}

int
vm_get_intinfo(struct vm *vm, int vcpuid, uint64_t *info1, uint64_t *info2)
{
        struct vcpu *vcpu;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        vcpu = &vm->vcpu[vcpuid];
        *info1 = vcpu->exit_intinfo;
        *info2 = vcpu->exc_pending;
        return (0);
}

int
vm_inject_exception(struct vm *vm, int vcpuid, uint8_t vector,
    bool errcode_valid, uint32_t errcode, bool restart_instruction)
{
        struct vcpu *vcpu;
        uint64_t regval;
        int error;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        if (vector >= 32)
                return (EINVAL);

        /*
         * NMIs are to be injected via their own specialized path using
         * vm_inject_nmi().
         */
        if (vector == IDT_NMI) {
                return (EINVAL);
        }

        /*
         * A double fault exception should never be injected directly into
         * the guest. It is a derived exception that results from specific
         * combinations of nested faults.
         */
        if (vector == IDT_DF) {
                return (EINVAL);
        }

        vcpu = &vm->vcpu[vcpuid];

        if (VM_INTINFO_PENDING(vcpu->exc_pending)) {
                /* Unable to inject exception due to one already pending */
                return (EBUSY);
        }

        if (errcode_valid) {
                /*
                 * Exceptions don't deliver an error code in real mode.
                 */
                error = vm_get_register(vm, vcpuid, VM_REG_GUEST_CR0, &regval);
                VERIFY0(error);
                if ((regval & CR0_PE) == 0) {
                        errcode_valid = false;
                }
        }

        /*
         * From section 26.6.1 "Interruptibility State" in Intel SDM:
         *
         * Event blocking by "STI" or "MOV SS" is cleared after guest executes
         * one instruction or incurs an exception.
         */
        error = vm_set_register(vm, vcpuid, VM_REG_GUEST_INTR_SHADOW, 0);
        VERIFY0(error);

        if (restart_instruction) {
                VERIFY0(vm_restart_instruction(vm, vcpuid));
        }

        uint64_t val = VM_INTINFO_VALID | VM_INTINFO_HWEXCP | vector;
        if (errcode_valid) {
                val |= VM_INTINFO_DEL_ERRCODE;
                val |= (uint64_t)errcode << VM_INTINFO_SHIFT_ERRCODE;
        }
        vcpu->exc_pending = val;
        return (0);
}

void
vm_inject_ud(struct vm *vm, int vcpuid)
{
        VERIFY0(vm_inject_exception(vm, vcpuid, IDT_UD, false, 0, true));
}

void
vm_inject_gp(struct vm *vm, int vcpuid)
{
        VERIFY0(vm_inject_exception(vm, vcpuid, IDT_GP, true, 0, true));
}

void
vm_inject_ac(struct vm *vm, int vcpuid, uint32_t errcode)
{
        VERIFY0(vm_inject_exception(vm, vcpuid, IDT_AC, true, errcode, true));
}

void
vm_inject_ss(struct vm *vm, int vcpuid, uint32_t errcode)
{
        VERIFY0(vm_inject_exception(vm, vcpuid, IDT_SS, true, errcode, true));
}

void
vm_inject_pf(struct vm *vm, int vcpuid, uint32_t errcode, uint64_t cr2)
{
        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_CR2, cr2));
        VERIFY0(vm_inject_exception(vm, vcpuid, IDT_PF, true, errcode, true));
}

static VMM_STAT(VCPU_NMI_COUNT, "number of NMIs delivered to vcpu");

int
vm_inject_nmi(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        vcpu = &vm->vcpu[vcpuid];

        vcpu->nmi_pending = true;
        vcpu_notify_event(vm, vcpuid);
        return (0);
}

bool
vm_nmi_pending(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];

        return (vcpu->nmi_pending);
}

void
vm_nmi_clear(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];

        ASSERT(vcpu->nmi_pending);

        vcpu->nmi_pending = false;
        vmm_stat_incr(vm, vcpuid, VCPU_NMI_COUNT, 1);
}

static VMM_STAT(VCPU_EXTINT_COUNT, "number of ExtINTs delivered to vcpu");

int
vm_inject_extint(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        vcpu = &vm->vcpu[vcpuid];

        vcpu->extint_pending = true;
        vcpu_notify_event(vm, vcpuid);
        return (0);
}

bool
vm_extint_pending(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];

        return (vcpu->extint_pending);
}

void
vm_extint_clear(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];

        ASSERT(vcpu->extint_pending);

        vcpu->extint_pending = false;
        vmm_stat_incr(vm, vcpuid, VCPU_EXTINT_COUNT, 1);
}

int
vm_inject_init(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        vcpu = &vm->vcpu[vcpuid];
        vcpu_lock(vcpu);
        vcpu->run_state |= VRS_PEND_INIT;
        /*
         * As part of queuing the INIT request, clear any pending SIPI.  It
         * would not otherwise survive across the reset of the vCPU when it
         * undergoes the requested INIT.  We would not want it to linger when it
         * could be mistaken as a subsequent (after the INIT) SIPI request.
         */
        vcpu->run_state &= ~VRS_PEND_SIPI;
        vcpu_notify_event_locked(vcpu, VCPU_NOTIFY_EXIT);

        vcpu_unlock(vcpu);
        return (0);
}

int
vm_inject_sipi(struct vm *vm, int vcpuid, uint8_t vector)
{
        struct vcpu *vcpu;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        vcpu = &vm->vcpu[vcpuid];
        vcpu_lock(vcpu);
        vcpu->run_state |= VRS_PEND_SIPI;
        vcpu->sipi_vector = vector;
        /* SIPI is only actionable if the CPU is waiting in INIT state */
        if ((vcpu->run_state & (VRS_INIT | VRS_RUN)) == VRS_INIT) {
                vcpu_notify_event_locked(vcpu, VCPU_NOTIFY_EXIT);
        }
        vcpu_unlock(vcpu);
        return (0);
}

bool
vcpu_run_state_pending(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu;

        ASSERT(vcpuid >= 0 && vcpuid < vm->maxcpus);
        vcpu = &vm->vcpu[vcpuid];

        /* Of interest: vCPU not in running state or with pending INIT */
        return ((vcpu->run_state & (VRS_RUN | VRS_PEND_INIT)) != VRS_RUN);
}

int
vcpu_arch_reset(struct vm *vm, int vcpuid, bool init_only)
{
        struct seg_desc desc;
        const enum vm_reg_name clear_regs[] = {
                VM_REG_GUEST_CR2,
                VM_REG_GUEST_CR3,
                VM_REG_GUEST_CR4,
                VM_REG_GUEST_RAX,
                VM_REG_GUEST_RBX,
                VM_REG_GUEST_RCX,
                VM_REG_GUEST_RSI,
                VM_REG_GUEST_RDI,
                VM_REG_GUEST_RBP,
                VM_REG_GUEST_RSP,
                VM_REG_GUEST_R8,
                VM_REG_GUEST_R9,
                VM_REG_GUEST_R10,
                VM_REG_GUEST_R11,
                VM_REG_GUEST_R12,
                VM_REG_GUEST_R13,
                VM_REG_GUEST_R14,
                VM_REG_GUEST_R15,
                VM_REG_GUEST_DR0,
                VM_REG_GUEST_DR1,
                VM_REG_GUEST_DR2,
                VM_REG_GUEST_DR3,
                VM_REG_GUEST_EFER,
        };
        const enum vm_reg_name data_segs[] = {
                VM_REG_GUEST_SS,
                VM_REG_GUEST_DS,
                VM_REG_GUEST_ES,
                VM_REG_GUEST_FS,
                VM_REG_GUEST_GS,
        };
        struct vcpu *vcpu = &vm->vcpu[vcpuid];

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        for (uint_t i = 0; i < nitems(clear_regs); i++) {
                VERIFY0(vm_set_register(vm, vcpuid, clear_regs[i], 0));
        }

        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, 2));
        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_RIP, 0xfff0));
        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_CR0, 0x60000010));

        /*
         * The prescribed contents of %rdx differ slightly between the Intel and
         * AMD architectural definitions.  The former expects the Extended Model
         * in bits 16-19 where the latter expects all the Family, Model, and
         * Stepping be there.  Common boot ROMs appear to disregard this
         * anyways, so we stick with a compromise value similar to what is
         * spelled out in the Intel SDM.
         */
        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_RDX, 0x600));

        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_DR6, 0xffff0ff0));
        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_DR7, 0x400));

        /* CS: Present, R/W, Accessed */
        desc.access = 0x0093;
        desc.base = 0xffff0000;
        desc.limit = 0xffff;
        VERIFY0(vm_set_seg_desc(vm, vcpuid, VM_REG_GUEST_CS, &desc));
        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_CS, 0xf000));

        /* SS, DS, ES, FS, GS: Present, R/W, Accessed */
        desc.access = 0x0093;
        desc.base = 0;
        desc.limit = 0xffff;
        for (uint_t i = 0; i < nitems(data_segs); i++) {
                VERIFY0(vm_set_seg_desc(vm, vcpuid, data_segs[i], &desc));
                VERIFY0(vm_set_register(vm, vcpuid, data_segs[i], 0));
        }

        /* GDTR, IDTR */
        desc.base = 0;
        desc.limit = 0xffff;
        VERIFY0(vm_set_seg_desc(vm, vcpuid, VM_REG_GUEST_GDTR, &desc));
        VERIFY0(vm_set_seg_desc(vm, vcpuid, VM_REG_GUEST_IDTR, &desc));

        /* LDTR: Present, LDT */
        desc.access = 0x0082;
        desc.base = 0;
        desc.limit = 0xffff;
        VERIFY0(vm_set_seg_desc(vm, vcpuid, VM_REG_GUEST_LDTR, &desc));
        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_LDTR, 0));

        /* TR: Present, 32-bit TSS */
        desc.access = 0x008b;
        desc.base = 0;
        desc.limit = 0xffff;
        VERIFY0(vm_set_seg_desc(vm, vcpuid, VM_REG_GUEST_TR, &desc));
        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_TR, 0));

        vlapic_reset(vm_lapic(vm, vcpuid));

        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_INTR_SHADOW, 0));

        vcpu->exit_intinfo = 0;
        vcpu->exc_pending = 0;
        vcpu->nmi_pending = false;
        vcpu->extint_pending = 0;

        /*
         * A CPU reset caused by power-on or system reset clears more state than
         * one which is trigged from an INIT IPI.
         */
        if (!init_only) {
                vcpu->guest_xcr0 = XFEATURE_ENABLED_X87;
                (void) hma_fpu_init(vcpu->guestfpu);

                /* XXX: clear MSRs and other pieces */
                bzero(&vcpu->mtrr, sizeof (vcpu->mtrr));
        }

        return (0);
}

static int
vcpu_vector_sipi(struct vm *vm, int vcpuid, uint8_t vector)
{
        struct seg_desc desc;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        /* CS: Present, R/W, Accessed */
        desc.access = 0x0093;
        desc.base = (uint64_t)vector << 12;
        desc.limit = 0xffff;
        VERIFY0(vm_set_seg_desc(vm, vcpuid, VM_REG_GUEST_CS, &desc));
        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_CS,
            (uint64_t)vector << 8));

        VERIFY0(vm_set_register(vm, vcpuid, VM_REG_GUEST_RIP, 0));

        return (0);
}

int
vm_get_capability(struct vm *vm, int vcpu, int type, int *retval)
{
        if (vcpu < 0 || vcpu >= vm->maxcpus)
                return (EINVAL);

        if (type < 0 || type >= VM_CAP_MAX)
                return (EINVAL);

        return (VMGETCAP(vm->cookie, vcpu, type, retval));
}

int
vm_set_capability(struct vm *vm, int vcpu, int type, int val)
{
        if (vcpu < 0 || vcpu >= vm->maxcpus)
                return (EINVAL);

        if (type < 0 || type >= VM_CAP_MAX)
                return (EINVAL);

        return (VMSETCAP(vm->cookie, vcpu, type, val));
}

vcpu_cpuid_config_t *
vm_cpuid_config(struct vm *vm, int vcpuid)
{
        ASSERT3S(vcpuid, >=, 0);
        ASSERT3S(vcpuid, <, VM_MAXCPU);

        return (&vm->vcpu[vcpuid].cpuid_cfg);
}

struct vlapic *
vm_lapic(struct vm *vm, int cpu)
{
        ASSERT3S(cpu, >=, 0);
        ASSERT3S(cpu, <, VM_MAXCPU);

        return (vm->vcpu[cpu].vlapic);
}

struct vioapic *
vm_ioapic(struct vm *vm)
{

        return (vm->vioapic);
}

struct vhpet *
vm_hpet(struct vm *vm)
{

        return (vm->vhpet);
}

void *
vm_iommu_domain(struct vm *vm)
{

        return (vm->iommu);
}

int
vcpu_set_state(struct vm *vm, int vcpuid, enum vcpu_state newstate,
    bool from_idle)
{
        int error;
        struct vcpu *vcpu;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                panic("vcpu_set_state: invalid vcpuid %d", vcpuid);

        vcpu = &vm->vcpu[vcpuid];

        vcpu_lock(vcpu);
        error = vcpu_set_state_locked(vm, vcpuid, newstate, from_idle);
        vcpu_unlock(vcpu);

        return (error);
}

enum vcpu_state
vcpu_get_state(struct vm *vm, int vcpuid, int *hostcpu)
{
        struct vcpu *vcpu;
        enum vcpu_state state;

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                panic("vcpu_get_state: invalid vcpuid %d", vcpuid);

        vcpu = &vm->vcpu[vcpuid];

        vcpu_lock(vcpu);
        state = vcpu->state;
        if (hostcpu != NULL)
                *hostcpu = vcpu->hostcpu;
        vcpu_unlock(vcpu);

        return (state);
}

/*
 * Calculate the TSC offset for a vCPU, applying physical CPU adjustments if
 * requested. The offset calculations include the VM-wide TSC offset.
 */
uint64_t
vcpu_tsc_offset(struct vm *vm, int vcpuid, bool phys_adj)
{
        ASSERT(vcpuid >= 0 && vcpuid < vm->maxcpus);

        uint64_t vcpu_off = vm->tsc_offset + vm->vcpu[vcpuid].tsc_offset;

        if (phys_adj) {
                /* Include any offset for the current physical CPU too */
                vcpu_off += vmm_host_tsc_delta();
        }

        return (vcpu_off);
}

uint64_t
vm_get_freq_multiplier(struct vm *vm)
{
        return (vm->freq_multiplier);
}

/* Normalize hrtime against the boot time for a VM */
hrtime_t
vm_normalize_hrtime(struct vm *vm, hrtime_t hrt)
{
        /* To avoid underflow/overflow UB, perform math as unsigned */
        return ((hrtime_t)((uint64_t)hrt - (uint64_t)vm->boot_hrtime));
}

/* Denormalize hrtime against the boot time for a VM */
hrtime_t
vm_denormalize_hrtime(struct vm *vm, hrtime_t hrt)
{
        /* To avoid underflow/overflow UB, perform math as unsigned */
        return ((hrtime_t)((uint64_t)hrt + (uint64_t)vm->boot_hrtime));
}

int
vm_activate_cpu(struct vm *vm, int vcpuid)
{

        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        if (CPU_ISSET(vcpuid, &vm->active_cpus))
                return (EBUSY);

        if (vm_is_suspended(vm, NULL)) {
                return (EBUSY);
        }

        CPU_SET_ATOMIC(vcpuid, &vm->active_cpus);

        /*
         * It is possible that this vCPU was undergoing activation at the same
         * time that the VM was being suspended.
         */
        if (vm_is_suspended(vm, NULL)) {
                return (EBUSY);
        }

        return (0);
}

int
vm_suspend_cpu(struct vm *vm, int vcpuid)
{
        int i;

        if (vcpuid < -1 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        if (vcpuid == -1) {
                vm->debug_cpus = vm->active_cpus;
                for (i = 0; i < vm->maxcpus; i++) {
                        if (CPU_ISSET(i, &vm->active_cpus))
                                vcpu_notify_event(vm, i);
                }
        } else {
                if (!CPU_ISSET(vcpuid, &vm->active_cpus))
                        return (EINVAL);

                CPU_SET_ATOMIC(vcpuid, &vm->debug_cpus);
                vcpu_notify_event(vm, vcpuid);
        }
        return (0);
}

int
vm_resume_cpu(struct vm *vm, int vcpuid)
{

        if (vcpuid < -1 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        if (vcpuid == -1) {
                CPU_ZERO(&vm->debug_cpus);
        } else {
                if (!CPU_ISSET(vcpuid, &vm->debug_cpus))
                        return (EINVAL);

                CPU_CLR_ATOMIC(vcpuid, &vm->debug_cpus);
        }
        return (0);
}

static bool
vcpu_bailout_checks(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        struct vm_exit *vme = &vcpu->exitinfo;

        ASSERT(vcpuid >= 0 && vcpuid < vm->maxcpus);

        /*
         * Check if VM is suspended, only passing the 'vm_exit *' to be
         * populated if this check is being performed as part of entry.
         */
        if (vm_is_suspended(vm, vme)) {
                /* Confirm exit details are as expected */
                VERIFY3S(vme->exitcode, ==, VM_EXITCODE_SUSPENDED);
                VERIFY(vme->u.suspended.how > VM_SUSPEND_NONE &&
                    vme->u.suspended.how < VM_SUSPEND_LAST);

                return (true);
        }
        if (vcpu->reqidle) {
                /*
                 * Another thread is trying to lock this vCPU and is waiting for
                 * it to enter the VCPU_IDLE state.  Take a lap with a BOGUS
                 * exit to allow other thread(s) access to this vCPU.
                 */
                vme->exitcode = VM_EXITCODE_BOGUS;
                vmm_stat_incr(vm, vcpuid, VMEXIT_REQIDLE, 1);
                return (true);
        }
        if (vcpu->reqbarrier) {
                /*
                 * Similar to 'reqidle', userspace has requested that this vCPU
                 * be pushed to a barrier by exiting to userspace.  Take that
                 * lap with BOGUS and clear the flag.
                 */
                vme->exitcode = VM_EXITCODE_BOGUS;
                vcpu->reqbarrier = false;
                return (true);
        }
        if (vcpu->reqconsist) {
                /*
                 * We only expect exit-when-consistent requests to be asserted
                 * during entry, not as an otherwise spontaneous condition.  As
                 * such, we do not count it among the exit statistics, and emit
                 * the expected BOGUS exitcode, while clearing the request.
                 */
                vme->exitcode = VM_EXITCODE_BOGUS;
                vcpu->reqconsist = false;
                return (true);
        }
        if (vcpu_should_yield(vm, vcpuid)) {
                vme->exitcode = VM_EXITCODE_BOGUS;
                vmm_stat_incr(vm, vcpuid, VMEXIT_ASTPENDING, 1);
                return (true);
        }
        if (CPU_ISSET(vcpuid, &vm->debug_cpus)) {
                vme->exitcode = VM_EXITCODE_DEBUG;
                return (true);
        }

        return (false);
}

static bool
vcpu_sleep_bailout_checks(struct vm *vm, int vcpuid)
{
        if (vcpu_bailout_checks(vm, vcpuid)) {
                struct vcpu *vcpu = &vm->vcpu[vcpuid];
                struct vm_exit *vme = &vcpu->exitinfo;

                /*
                 * Bail-out check done prior to sleeping (in vCPU contexts like
                 * HLT or wait-for-SIPI) expect that %rip is already populated
                 * in the vm_exit structure, and we would only modify the
                 * exitcode and clear the inst_length.
                 */
                vme->inst_length = 0;
                return (true);
        }
        return (false);
}

bool
vcpu_entry_bailout_checks(struct vm *vm, int vcpuid, uint64_t rip)
{
        if (vcpu_bailout_checks(vm, vcpuid)) {
                struct vcpu *vcpu = &vm->vcpu[vcpuid];
                struct vm_exit *vme = &vcpu->exitinfo;

                /*
                 * Bail-out checks done as part of VM entry require an updated
                 * %rip to populate the vm_exit struct if any of the conditions
                 * of interest are matched in the check.
                 */
                vme->rip = rip;
                vme->inst_length = 0;
                return (true);
        }
        return (false);
}

int
vm_vcpu_barrier(struct vm *vm, int vcpuid)
{
        if (vcpuid >= 0 && vcpuid < vm->maxcpus) {
                struct vcpu *vcpu = &vm->vcpu[vcpuid];

                /* Push specified vCPU to barrier */
                vcpu_lock(vcpu);
                if (CPU_ISSET(vcpuid, &vm->active_cpus)) {
                        vcpu->reqbarrier = true;
                        vcpu_notify_event_locked(vcpu, VCPU_NOTIFY_EXIT);
                }
                vcpu_unlock(vcpu);

                return (0);
        } else if (vcpuid == -1) {
                /* Push all (active) vCPUs to barrier */
                for (int i = 0; i < vm->maxcpus; i++) {
                        struct vcpu *vcpu = &vm->vcpu[i];

                        vcpu_lock(vcpu);
                        if (CPU_ISSET(vcpuid, &vm->active_cpus)) {
                                vcpu->reqbarrier = true;
                                vcpu_notify_event_locked(vcpu,
                                    VCPU_NOTIFY_EXIT);
                        }
                        vcpu_unlock(vcpu);
                }

                return (0);
        } else {
                return (EINVAL);
        }
}

cpuset_t
vm_active_cpus(struct vm *vm)
{
        return (vm->active_cpus);
}

cpuset_t
vm_debug_cpus(struct vm *vm)
{
        return (vm->debug_cpus);
}

void *
vcpu_stats(struct vm *vm, int vcpuid)
{

        return (vm->vcpu[vcpuid].stats);
}

int
vm_get_x2apic_state(struct vm *vm, int vcpuid, enum x2apic_state *state)
{
        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        *state = vm->vcpu[vcpuid].x2apic_state;

        return (0);
}

int
vm_set_x2apic_state(struct vm *vm, int vcpuid, enum x2apic_state state)
{
        if (vcpuid < 0 || vcpuid >= vm->maxcpus)
                return (EINVAL);

        if (state >= X2APIC_STATE_LAST)
                return (EINVAL);

        vm->vcpu[vcpuid].x2apic_state = state;

        vlapic_set_x2apic_state(vm, vcpuid, state);

        return (0);
}

/*
 * This function is called to ensure that a vcpu "sees" a pending event
 * as soon as possible:
 * - If the vcpu thread is sleeping then it is woken up.
 * - If the vcpu is running on a different host_cpu then an IPI will be directed
 *   to the host_cpu to cause the vcpu to trap into the hypervisor.
 */
static void
vcpu_notify_event_locked(struct vcpu *vcpu, vcpu_notify_t ntype)
{
        int hostcpu;

        ASSERT(ntype == VCPU_NOTIFY_APIC || VCPU_NOTIFY_EXIT);

        hostcpu = vcpu->hostcpu;
        if (vcpu->state == VCPU_RUNNING) {
                KASSERT(hostcpu != NOCPU, ("vcpu running on invalid hostcpu"));
                if (hostcpu != curcpu) {
                        if (ntype == VCPU_NOTIFY_APIC) {
                                vlapic_post_intr(vcpu->vlapic, hostcpu);
                        } else {
                                poke_cpu(hostcpu);
                        }
                } else {
                        /*
                         * If the 'vcpu' is running on 'curcpu' then it must
                         * be sending a notification to itself (e.g. SELF_IPI).
                         * The pending event will be picked up when the vcpu
                         * transitions back to guest context.
                         */
                }
        } else {
                KASSERT(hostcpu == NOCPU, ("vcpu state %d not consistent "
                    "with hostcpu %d", vcpu->state, hostcpu));
                if (vcpu->state == VCPU_SLEEPING) {
                        cv_signal(&vcpu->vcpu_cv);
                }
        }
}

void
vcpu_notify_event(struct vm *vm, int vcpuid)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];

        vcpu_lock(vcpu);
        vcpu_notify_event_locked(vcpu, VCPU_NOTIFY_EXIT);
        vcpu_unlock(vcpu);
}

void
vcpu_notify_event_type(struct vm *vm, int vcpuid, vcpu_notify_t ntype)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];

        if (ntype == VCPU_NOTIFY_NONE) {
                return;
        }

        vcpu_lock(vcpu);
        vcpu_notify_event_locked(vcpu, ntype);
        vcpu_unlock(vcpu);
}

void
vcpu_ustate_change(struct vm *vm, int vcpuid, enum vcpu_ustate ustate)
{
        struct vcpu *vcpu = &vm->vcpu[vcpuid];
        const hrtime_t now = gethrtime();

        ASSERT3S(ustate, <, VU_MAX);
        ASSERT3S(ustate, >=, VU_INIT);

        if (ustate == vcpu->ustate) {
                return;
        }

        const hrtime_t delta = now - vcpu->ustate_when;
        vcpu->ustate_total[vcpu->ustate] += delta;

        membar_producer();

        vcpu->ustate_when = now;
        vcpu->ustate = ustate;
}

void *
vm_get_cookie(struct vm *vm)
{
        return (vm->cookie);
}

struct vmspace *
vm_get_vmspace(struct vm *vm)
{

        return (vm->vmspace);
}

struct vm_client *
vm_get_vmclient(struct vm *vm, int vcpuid)
{
        return (vm->vcpu[vcpuid].vmclient);
}

int
vm_apicid2vcpuid(struct vm *vm, int apicid)
{
        /*
         * XXX apic id is assumed to be numerically identical to vcpu id
         */
        return (apicid);
}

struct vatpic *
vm_atpic(struct vm *vm)
{
        return (vm->vatpic);
}

struct vatpit *
vm_atpit(struct vm *vm)
{
        return (vm->vatpit);
}

struct vpmtmr *
vm_pmtmr(struct vm *vm)
{

        return (vm->vpmtmr);
}

struct vrtc *
vm_rtc(struct vm *vm)
{

        return (vm->vrtc);
}

enum vm_reg_name
vm_segment_name(int seg)
{
        static enum vm_reg_name seg_names[] = {
                VM_REG_GUEST_ES,
                VM_REG_GUEST_CS,
                VM_REG_GUEST_SS,
                VM_REG_GUEST_DS,
                VM_REG_GUEST_FS,
                VM_REG_GUEST_GS
        };

        KASSERT(seg >= 0 && seg < nitems(seg_names),
            ("%s: invalid segment encoding %d", __func__, seg));
        return (seg_names[seg]);
}

void
vm_copy_teardown(struct vm *vm, int vcpuid, struct vm_copyinfo *copyinfo,
    uint_t num_copyinfo)
{
        for (uint_t idx = 0; idx < num_copyinfo; idx++) {
                if (copyinfo[idx].cookie != NULL) {
                        (void) vmp_release((vm_page_t *)copyinfo[idx].cookie);
                }
        }
        bzero(copyinfo, num_copyinfo * sizeof (struct vm_copyinfo));
}

int
vm_copy_setup(struct vm *vm, int vcpuid, struct vm_guest_paging *paging,
    uint64_t gla, size_t len, int prot, struct vm_copyinfo *copyinfo,
    uint_t num_copyinfo, int *fault)
{
        uint_t idx, nused;
        size_t n, off, remaining;
        vm_client_t *vmc = vm_get_vmclient(vm, vcpuid);

        bzero(copyinfo, sizeof (struct vm_copyinfo) * num_copyinfo);

        nused = 0;
        remaining = len;
        while (remaining > 0) {
                uint64_t gpa;
                int error;

                if (nused >= num_copyinfo)
                        return (EFAULT);
                error = vm_gla2gpa(vm, vcpuid, paging, gla, prot, &gpa, fault);
                if (error || *fault)
                        return (error);
                off = gpa & PAGEOFFSET;
                n = min(remaining, PAGESIZE - off);
                copyinfo[nused].gpa = gpa;
                copyinfo[nused].len = n;
                remaining -= n;
                gla += n;
                nused++;
        }

        for (idx = 0; idx < nused; idx++) {
                vm_page_t *vmp;
                caddr_t hva;

                vmp = vmc_hold(vmc, copyinfo[idx].gpa & PAGEMASK, prot);
                if (vmp == NULL) {
                        break;
                }
                if ((prot & PROT_WRITE) != 0) {
                        hva = (caddr_t)vmp_get_writable(vmp);
                } else {
                        hva = (caddr_t)vmp_get_readable(vmp);
                }
                copyinfo[idx].hva = hva + (copyinfo[idx].gpa & PAGEOFFSET);
                copyinfo[idx].cookie = vmp;
                copyinfo[idx].prot = prot;
        }

        if (idx != nused) {
                vm_copy_teardown(vm, vcpuid, copyinfo, num_copyinfo);
                return (EFAULT);
        } else {
                *fault = 0;
                return (0);
        }
}

void
vm_copyin(struct vm *vm, int vcpuid, struct vm_copyinfo *copyinfo, void *kaddr,
    size_t len)
{
        char *dst;
        int idx;

        dst = kaddr;
        idx = 0;
        while (len > 0) {
                ASSERT(copyinfo[idx].prot & PROT_READ);

                bcopy(copyinfo[idx].hva, dst, copyinfo[idx].len);
                len -= copyinfo[idx].len;
                dst += copyinfo[idx].len;
                idx++;
        }
}

void
vm_copyout(struct vm *vm, int vcpuid, const void *kaddr,
    struct vm_copyinfo *copyinfo, size_t len)
{
        const char *src;
        int idx;

        src = kaddr;
        idx = 0;
        while (len > 0) {
                ASSERT(copyinfo[idx].prot & PROT_WRITE);

                bcopy(src, copyinfo[idx].hva, copyinfo[idx].len);
                len -= copyinfo[idx].len;
                src += copyinfo[idx].len;
                idx++;
        }
}

/*
 * Return the amount of in-use and wired memory for the VM. Since
 * these are global stats, only return the values with for vCPU 0
 */
VMM_STAT_DECLARE(VMM_MEM_RESIDENT);

static void
vm_get_rescnt(struct vm *vm, int vcpu, struct vmm_stat_type *stat)
{
        if (vcpu == 0) {
                vmm_stat_set(vm, vcpu, VMM_MEM_RESIDENT,
                    PAGE_SIZE * vmspace_resident_count(vm->vmspace));
        }
}

VMM_STAT_FUNC(VMM_MEM_RESIDENT, "Resident memory", vm_get_rescnt);

int
vm_ioport_access(struct vm *vm, int vcpuid, bool in, uint16_t port,
    uint8_t bytes, uint32_t *val)
{
        return (vm_inout_access(&vm->ioports, in, port, bytes, val));
}

/*
 * bhyve-internal interfaces to attach or detach IO port handlers.
 * Must be called with VM write lock held for safety.
 */
int
vm_ioport_attach(struct vm *vm, uint16_t port, ioport_handler_t func, void *arg,
    void **cookie)
{
        int err;
        err = vm_inout_attach(&vm->ioports, port, IOPF_DEFAULT, func, arg);
        if (err == 0) {
                *cookie = (void *)IOP_GEN_COOKIE(func, arg, port);
        }
        return (err);
}
int
vm_ioport_detach(struct vm *vm, void **cookie, ioport_handler_t *old_func,
    void **old_arg)
{
        uint16_t port = IOP_PORT_FROM_COOKIE((uintptr_t)*cookie);
        int err;

        err = vm_inout_detach(&vm->ioports, port, false, old_func, old_arg);
        if (err == 0) {
                *cookie = NULL;
        }
        return (err);
}

/*
 * External driver interfaces to attach or detach IO port handlers.
 * Must be called with VM write lock held for safety.
 */
int
vm_ioport_hook(struct vm *vm, uint16_t port, ioport_handler_t func,
    void *arg, void **cookie)
{
        int err;

        if (port == 0) {
                return (EINVAL);
        }

        err = vm_inout_attach(&vm->ioports, port, IOPF_DRV_HOOK, func, arg);
        if (err == 0) {
                *cookie = (void *)IOP_GEN_COOKIE(func, arg, port);
        }
        return (err);
}
void
vm_ioport_unhook(struct vm *vm, void **cookie)
{
        uint16_t port = IOP_PORT_FROM_COOKIE((uintptr_t)*cookie);
        ioport_handler_t old_func;
        void *old_arg;
        int err;

        err = vm_inout_detach(&vm->ioports, port, true, &old_func, &old_arg);

        /* ioport-hook-using drivers are expected to be well-behaved */
        VERIFY0(err);
        VERIFY(IOP_GEN_COOKIE(old_func, old_arg, port) == (uintptr_t)*cookie);

        *cookie = NULL;
}

int
vmm_kstat_update_vcpu(struct kstat *ksp, int rw)
{
        struct vm *vm = ksp->ks_private;
        vmm_vcpu_kstats_t *vvk = ksp->ks_data;
        const int vcpuid = vvk->vvk_vcpu.value.ui32;
        struct vcpu *vcpu = &vm->vcpu[vcpuid];

        ASSERT3U(vcpuid, <, VM_MAXCPU);

        vvk->vvk_time_init.value.ui64 = vcpu->ustate_total[VU_INIT];
        vvk->vvk_time_run.value.ui64 = vcpu->ustate_total[VU_RUN];
        vvk->vvk_time_idle.value.ui64 = vcpu->ustate_total[VU_IDLE];
        vvk->vvk_time_emu_kern.value.ui64 = vcpu->ustate_total[VU_EMU_KERN];
        vvk->vvk_time_emu_user.value.ui64 = vcpu->ustate_total[VU_EMU_USER];
        vvk->vvk_time_sched.value.ui64 = vcpu->ustate_total[VU_SCHED];

        return (0);
}

SET_DECLARE(vmm_data_version_entries, const vmm_data_version_entry_t);

static int
vmm_data_find(const vmm_data_req_t *req, const vmm_data_version_entry_t **resp)
{
        const vmm_data_version_entry_t **vdpp, *vdp;

        ASSERT(resp != NULL);
        ASSERT(req->vdr_result_len != NULL);

        SET_FOREACH(vdpp, vmm_data_version_entries) {
                vdp = *vdpp;
                if (vdp->vdve_class != req->vdr_class ||
                    vdp->vdve_version != req->vdr_version) {
                        continue;
                }

                /*
                 * Enforce any data length expectation expressed by the provider
                 * for this data.
                 */
                if (vdp->vdve_len_expect != 0 &&
                    vdp->vdve_len_expect > req->vdr_len) {
                        *req->vdr_result_len = vdp->vdve_len_expect;
                        return (ENOSPC);
                }

                /*
                 * Make sure that the provided vcpuid is acceptable for the
                 * backend handler.
                 */
                if (vdp->vdve_readf != NULL || vdp->vdve_writef != NULL) {
                        /*
                         * While it is tempting to demand the -1 sentinel value
                         * in vcpuid here, that expectation was not established
                         * for early consumers, so it is ignored.
                         */
                } else if (vdp->vdve_vcpu_readf != NULL ||
                    vdp->vdve_vcpu_writef != NULL) {
                        /*
                         * Per-vCPU handlers which permit "wildcard" access will
                         * accept a vcpuid of -1 (for VM-wide data), while all
                         * others expect vcpuid [0, VM_MAXCPU).
                         */
                        const int llimit = vdp->vdve_vcpu_wildcard ? -1 : 0;
                        if (req->vdr_vcpuid < llimit ||
                            req->vdr_vcpuid >= VM_MAXCPU) {
                                return (EINVAL);
                        }
                } else {
                        /*
                         * A provider with neither VM-wide nor per-vCPU handlers
                         * is completely unexpected.  Such a situation should be
                         * made into a compile-time error.  Bail out for now,
                         * rather than punishing the user with a panic.
                         */
                        return (EINVAL);
                }


                *resp = vdp;
                return (0);
        }
        return (EINVAL);
}

static void *
vmm_data_from_class(const vmm_data_req_t *req, struct vm *vm)
{
        switch (req->vdr_class) {
        case VDC_REGISTER:
        case VDC_MSR:
        case VDC_FPU:
        case VDC_LAPIC:
        case VDC_VMM_ARCH:
                /*
                 * These have per-CPU handling which is dispatched outside
                 * vmm_data_version_entries listing.
                 */
                panic("Unexpected per-vcpu class %u", req->vdr_class);
                break;

        case VDC_IOAPIC:
                return (vm->vioapic);
        case VDC_ATPIT:
                return (vm->vatpit);
        case VDC_ATPIC:
                return (vm->vatpic);
        case VDC_HPET:
                return (vm->vhpet);
        case VDC_PM_TIMER:
                return (vm->vpmtmr);
        case VDC_RTC:
                return (vm->vrtc);
        case VDC_VMM_TIME:
                return (vm);
        case VDC_VERSION:
                /*
                 * Play along with all of the other classes which need backup
                 * data, even though version info does not require it.
                 */
                return (vm);

        default:
                /* The data class will have been validated by now */
                panic("Unexpected class %u", req->vdr_class);
        }
}

const uint32_t default_msr_iter[] = {
        /*
         * Although EFER is also available via the get/set-register interface,
         * we include it in the default list of emitted MSRs.
         */
        MSR_EFER,

        /*
         * While gsbase and fsbase are accessible via the MSR accessors, they
         * are not included in MSR iteration since they are covered by the
         * segment descriptor interface too.
         */
        MSR_KGSBASE,

        MSR_STAR,
        MSR_LSTAR,
        MSR_CSTAR,
        MSR_SF_MASK,

        MSR_SYSENTER_CS_MSR,
        MSR_SYSENTER_ESP_MSR,
        MSR_SYSENTER_EIP_MSR,

        MSR_PAT,

        MSR_TSC,

        MSR_MTRRcap,
        MSR_MTRRdefType,
        MSR_MTRR4kBase, MSR_MTRR4kBase + 1, MSR_MTRR4kBase + 2,
        MSR_MTRR4kBase + 3, MSR_MTRR4kBase + 4, MSR_MTRR4kBase + 5,
        MSR_MTRR4kBase + 6, MSR_MTRR4kBase + 7,
        MSR_MTRR16kBase, MSR_MTRR16kBase + 1,
        MSR_MTRR64kBase,
};

static int
vmm_data_read_msr(struct vm *vm, int vcpuid, uint32_t msr, uint64_t *value)
{
        int err = 0;

        switch (msr) {
        case MSR_TSC:
                /*
                 * The vmm-data interface for MSRs provides access to the
                 * per-vCPU offset of the TSC, when reading/writing MSR_TSC.
                 *
                 * The VM-wide offset (and scaling) of the guest TSC is accessed
                 * via the VMM_TIME data class.
                 */
                *value = vm->vcpu[vcpuid].tsc_offset;
                return (0);

        default:
                if (is_mtrr_msr(msr)) {
                        err = vm_rdmtrr(&vm->vcpu[vcpuid].mtrr, msr, value);
                } else {
                        err = ops->vmgetmsr(vm->cookie, vcpuid, msr, value);
                }
                break;
        }

        return (err);
}

static int
vmm_data_write_msr(struct vm *vm, int vcpuid, uint32_t msr, uint64_t value)
{
        int err = 0;

        switch (msr) {
        case MSR_TSC:
                /* See vmm_data_read_msr() for more detail */
                vm->vcpu[vcpuid].tsc_offset = value;
                return (0);
        case MSR_MTRRcap: {
                /*
                 * MTRRcap is read-only.  If the desired value matches the
                 * existing one, consider it a success.
                 */
                uint64_t comp;
                err = vm_rdmtrr(&vm->vcpu[vcpuid].mtrr, msr, &comp);
                if (err == 0 && comp != value) {
                        return (EINVAL);
                }
                break;
        }
        default:
                if (is_mtrr_msr(msr)) {
                        /* MTRRcap is already handled above */
                        ASSERT3U(msr, !=, MSR_MTRRcap);

                        err = vm_wrmtrr(&vm->vcpu[vcpuid].mtrr, msr, value);
                } else {
                        err = ops->vmsetmsr(vm->cookie, vcpuid, msr, value);
                }
                break;
        }

        return (err);
}

static int
vmm_data_read_msrs(struct vm *vm, int vcpuid, const vmm_data_req_t *req)
{
        VERIFY3U(req->vdr_class, ==, VDC_MSR);
        VERIFY3U(req->vdr_version, ==, 1);

        struct vdi_field_entry_v1 *entryp = req->vdr_data;

        /* Specific MSRs requested */
        if ((req->vdr_flags & VDX_FLAG_READ_COPYIN) != 0) {
                const uint_t count =
                    req->vdr_len / sizeof (struct vdi_field_entry_v1);

                for (uint_t i = 0; i < count; i++, entryp++) {
                        int err = vmm_data_read_msr(vm, vcpuid,
                            entryp->vfe_ident, &entryp->vfe_value);

                        if (err != 0) {
                                return (err);
                        }
                }

                *req->vdr_result_len =
                    count * sizeof (struct vdi_field_entry_v1);
                return (0);
        }

        /*
         * If specific MSRs are not requested, try to provide all those which we
         * know about instead.
         */
        const uint_t num_msrs = nitems(default_msr_iter) +
            (VMM_MTRR_VAR_MAX * 2);
        const uint32_t output_len =
            num_msrs * sizeof (struct vdi_field_entry_v1);

        *req->vdr_result_len = output_len;
        if (req->vdr_len < output_len) {
                return (ENOSPC);
        }

        /* Output the MSRs in the default list */
        for (uint_t i = 0; i < nitems(default_msr_iter); i++, entryp++) {
                entryp->vfe_ident = default_msr_iter[i];

                /* All of these MSRs are expected to work */
                VERIFY0(vmm_data_read_msr(vm, vcpuid, entryp->vfe_ident,
                    &entryp->vfe_value));
        }

        /* Output the variable MTRRs */
        for (uint_t i = 0; i < (VMM_MTRR_VAR_MAX * 2); i++, entryp++) {
                entryp->vfe_ident = MSR_MTRRVarBase + i;

                /* All of these MSRs are expected to work */
                VERIFY0(vmm_data_read_msr(vm, vcpuid, entryp->vfe_ident,
                    &entryp->vfe_value));
        }
        return (0);
}

static int
vmm_data_write_msrs(struct vm *vm, int vcpuid, const vmm_data_req_t *req)
{
        VERIFY3U(req->vdr_class, ==, VDC_MSR);
        VERIFY3U(req->vdr_version, ==, 1);

        const struct vdi_field_entry_v1 *entryp = req->vdr_data;
        const uint_t entry_count =
            req->vdr_len / sizeof (struct vdi_field_entry_v1);

        /*
         * First make sure that all of the MSRs can be manipulated.
         * For now, this check is done by going though the getmsr handler
         */
        for (uint_t i = 0; i < entry_count; i++, entryp++) {
                const uint64_t msr = entryp->vfe_ident;
                uint64_t val;

                if (vmm_data_read_msr(vm, vcpuid, msr, &val) != 0) {
                        return (EINVAL);
                }
        }

        /*
         * Fairly confident that all of the 'set' operations are at least
         * targeting valid MSRs, continue on.
         */
        entryp = req->vdr_data;
        for (uint_t i = 0; i < entry_count; i++, entryp++) {
                int err = vmm_data_write_msr(vm, vcpuid, entryp->vfe_ident,
                    entryp->vfe_value);

                if (err != 0) {
                        return (err);
                }
        }
        *req->vdr_result_len = entry_count * sizeof (struct vdi_field_entry_v1);

        return (0);
}

static const vmm_data_version_entry_t msr_v1 = {
        .vdve_class = VDC_MSR,
        .vdve_version = 1,
        .vdve_len_per_item = sizeof (struct vdi_field_entry_v1),
        .vdve_vcpu_readf = vmm_data_read_msrs,
        .vdve_vcpu_writef = vmm_data_write_msrs,
};
VMM_DATA_VERSION(msr_v1);

static const uint32_t vmm_arch_v1_fields[] = {
        VAI_VM_IS_PAUSED,
};

static const uint32_t vmm_arch_v1_vcpu_fields[] = {
        VAI_PEND_NMI,
        VAI_PEND_EXTINT,
        VAI_PEND_EXCP,
        VAI_PEND_INTINFO,
};

static bool
vmm_read_arch_field(struct vm *vm, int vcpuid, uint32_t ident, uint64_t *valp)
{
        ASSERT(valp != NULL);

        if (vcpuid == -1) {
                switch (ident) {
                case VAI_VM_IS_PAUSED:
                        *valp = vm->is_paused ? 1 : 0;
                        return (true);
                default:
                        break;
                }
        } else {
                VERIFY(vcpuid >= 0 && vcpuid <= VM_MAXCPU);

                struct vcpu *vcpu = &vm->vcpu[vcpuid];
                switch (ident) {
                case VAI_PEND_NMI:
                        *valp = vcpu->nmi_pending != 0 ? 1 : 0;
                        return (true);
                case VAI_PEND_EXTINT:
                        *valp = vcpu->extint_pending != 0 ? 1 : 0;
                        return (true);
                case VAI_PEND_EXCP:
                        *valp = vcpu->exc_pending;
                        return (true);
                case VAI_PEND_INTINFO:
                        *valp = vcpu->exit_intinfo;
                        return (true);
                default:
                        break;
                }
        }
        return (false);
}

static int
vmm_data_read_varch(struct vm *vm, int vcpuid, const vmm_data_req_t *req)
{
        VERIFY3U(req->vdr_class, ==, VDC_VMM_ARCH);
        VERIFY3U(req->vdr_version, ==, 1);

        /* per-vCPU fields are handled separately from VM-wide ones */
        if (vcpuid != -1 && (vcpuid < 0 || vcpuid >= VM_MAXCPU)) {
                return (EINVAL);
        }

        struct vdi_field_entry_v1 *entryp = req->vdr_data;

        /* Specific fields requested */
        if ((req->vdr_flags & VDX_FLAG_READ_COPYIN) != 0) {
                const uint_t count =
                    req->vdr_len / sizeof (struct vdi_field_entry_v1);

                for (uint_t i = 0; i < count; i++, entryp++) {
                        if (!vmm_read_arch_field(vm, vcpuid, entryp->vfe_ident,
                            &entryp->vfe_value)) {
                                return (EINVAL);
                        }
                }
                *req->vdr_result_len =
                    count * sizeof (struct vdi_field_entry_v1);
                return (0);
        }

        /* Emit all of the possible values */
        const uint32_t *idents;
        uint_t ident_count;

        if (vcpuid == -1) {
                idents = vmm_arch_v1_fields;
                ident_count = nitems(vmm_arch_v1_fields);
        } else {
                idents = vmm_arch_v1_vcpu_fields;
                ident_count = nitems(vmm_arch_v1_vcpu_fields);

        }

        const uint32_t total_size =
            ident_count * sizeof (struct vdi_field_entry_v1);

        *req->vdr_result_len = total_size;
        if (req->vdr_len < total_size) {
                return (ENOSPC);
        }
        for (uint_t i = 0; i < ident_count; i++, entryp++) {
                entryp->vfe_ident = idents[i];
                VERIFY(vmm_read_arch_field(vm, vcpuid, entryp->vfe_ident,
                    &entryp->vfe_value));
        }
        return (0);
}

static int
vmm_data_write_varch_vcpu(struct vm *vm, int vcpuid, const vmm_data_req_t *req)
{
        VERIFY3U(req->vdr_class, ==, VDC_VMM_ARCH);
        VERIFY3U(req->vdr_version, ==, 1);

        if (vcpuid < 0 || vcpuid >= VM_MAXCPU) {
                return (EINVAL);
        }

        const struct vdi_field_entry_v1 *entryp = req->vdr_data;
        const uint_t entry_count =
            req->vdr_len / sizeof (struct vdi_field_entry_v1);
        struct vcpu *vcpu = &vm->vcpu[vcpuid];

        for (uint_t i = 0; i < entry_count; i++, entryp++) {
                const uint64_t val = entryp->vfe_value;

                switch (entryp->vfe_ident) {
                case VAI_PEND_NMI:
                        vcpu->nmi_pending = (val != 0);
                        break;
                case VAI_PEND_EXTINT:
                        vcpu->extint_pending = (val != 0);
                        break;
                case VAI_PEND_EXCP:
                        if (!VM_INTINFO_PENDING(val)) {
                                vcpu->exc_pending = 0;
                        } else if (VM_INTINFO_TYPE(val) != VM_INTINFO_HWEXCP ||
                            (val & VM_INTINFO_MASK_RSVD) != 0) {
                                /* reject improperly-formed hw exception */
                                return (EINVAL);
                        } else {
                                vcpu->exc_pending = val;
                        }
                        break;
                case VAI_PEND_INTINFO:
                        if (vm_exit_intinfo(vm, vcpuid, val) != 0) {
                                return (EINVAL);
                        }
                        break;
                default:
                        return (EINVAL);
                }
        }

        *req->vdr_result_len = entry_count * sizeof (struct vdi_field_entry_v1);
        return (0);
}

static int
vmm_data_write_varch(struct vm *vm, int vcpuid, const vmm_data_req_t *req)
{
        VERIFY3U(req->vdr_class, ==, VDC_VMM_ARCH);
        VERIFY3U(req->vdr_version, ==, 1);

        /* per-vCPU fields are handled separately from VM-wide ones */
        if (vcpuid != -1) {
                return (vmm_data_write_varch_vcpu(vm, vcpuid, req));
        }

        const struct vdi_field_entry_v1 *entryp = req->vdr_data;
        const uint_t entry_count =
            req->vdr_len / sizeof (struct vdi_field_entry_v1);

        if (entry_count > 0) {
                if (entryp->vfe_ident == VAI_VM_IS_PAUSED) {
                        /*
                         * The VM_PAUSE and VM_RESUME ioctls are the officially
                         * sanctioned mechanisms for setting the is-paused state
                         * of the VM.
                         */
                        return (EPERM);
                } else {
                        /* no other valid arch entries at this time */
                        return (EINVAL);
                }
        }

        *req->vdr_result_len = entry_count * sizeof (struct vdi_field_entry_v1);
        return (0);
}

static const vmm_data_version_entry_t vmm_arch_v1 = {
        .vdve_class = VDC_VMM_ARCH,
        .vdve_version = 1,
        .vdve_len_per_item = sizeof (struct vdi_field_entry_v1),
        .vdve_vcpu_readf = vmm_data_read_varch,
        .vdve_vcpu_writef = vmm_data_write_varch,

        /*
         * Handlers for VMM_ARCH can process VM-wide (vcpuid == -1) entries in
         * addition to vCPU specific ones.
         */
        .vdve_vcpu_wildcard = true,
};
VMM_DATA_VERSION(vmm_arch_v1);


/*
 * GUEST TIME SUPPORT
 *
 * Broadly, there are two categories of functionality related to time passing in
 * the guest: the guest's TSC and timers used by emulated devices.
 *
 * ---------------------------
 * GUEST TSC "VIRTUALIZATION"
 * ---------------------------
 *
 * The TSC can be read either via an instruction (rdtsc/rdtscp) or by reading
 * the TSC MSR.
 *
 * When a guest reads the TSC via its MSR, the guest will exit and we emulate
 * the rdmsr. More typically, the guest reads the TSC via a rdtsc(p)
 * instruction. Both SVM and VMX support virtualizing the guest TSC in hardware
 * -- that is, a guest will not generally exit on a rdtsc instruction.
 *
 * To support hardware-virtualized guest TSC, both SVM and VMX provide two knobs
 * for the hypervisor to adjust the guest's view of the TSC:
 * - TSC offset
 * - TSC frequency multiplier (also called "frequency ratio")
 *
 * When a guest calls rdtsc(p), the TSC value it sees is the sum of:
 *     guest_tsc = (host TSC, scaled according to frequency multiplier)
 *                  + (TSC offset, programmed by hypervisor)
 *
 * See the discussions of the TSC offset and frequency multiplier below for more
 * details on each of these.
 *
 * --------------------
 * TSC OFFSET OVERVIEW
 * --------------------
 *
 * The TSC offset is a value added to the host TSC (which may be scaled first)
 * to provide the guest TSC. This offset addition is generally done by hardware,
 * but may be used in emulating the TSC if necessary.
 *
 * Recall that general formula for calculating the guest TSC is:
 *
 *      guest_tsc = (host TSC, scaled if needed) + TSC offset
 *
 * Intuitively, the TSC offset is simply an offset of the host's TSC to make the
 * guest's view of the TSC appear correct: The guest TSC should be 0 at boot and
 * monotonically increase at a roughly constant frequency. Thus in the simplest
 * case, the TSC offset is just the negated value of the host TSC when the guest
 * was booted, assuming they have the same frequencies.
 *
 * In practice, there are several factors that can make calculating the TSC
 * offset more complicated, including:
 *
 * (1) the physical CPU the guest is running on
 * (2) whether the guest has written to the TSC of that vCPU
 * (3) differing host and guest frequencies, like after a live migration
 * (4) a guest running on a different system than where it was booted, like
 *     after a live migration
 *
 * We will explore each of these factors individually. See below for a
 * summary.
 *
 *
 * (1) Physical CPU offsets
 *
 * The system maintains a set of per-CPU offsets to the TSC to provide a
 * consistent view of the TSC regardless of the CPU a thread is running on.
 * These offsets are included automatically as a part of rdtsc_offset().
 *
 * The per-CPU offset must be included as a part reading the host TSC when
 * calculating the offset before running the guest on a given CPU.
 *
 *
 * (2) Guest TSC writes (vCPU offsets)
 *
 * The TSC is a writable MSR. When a guest writes to the TSC, this operation
 * should result in the TSC, when read from that vCPU, shows the value written,
 * plus whatever time has elapsed since the read.
 *
 * To support this, when the guest writes to the TSC, we store an additional
 * vCPU offset calculated to make future reads of the TSC map to what the guest
 * expects.
 *
 *
 * (3) Differing host and guest frequencies (host TSC scaling)
 *
 * A guest has the same frequency of its host when it boots, but it may be
 * migrated to a machine with a different TSC frequency. Systems expect that
 * their TSC frequency does not change. To support this fiction in which a guest
 * is running on hardware of a different TSC frequency, the hypervisor  can
 * program a "frequency multiplier" that represents the ratio of guest/host
 * frequency.
 *
 * Any time a host TSC is used in calculations for the offset, it should be
 * "scaled" according to this multiplier, and the hypervisor should program the
 * multiplier before running a guest so that the hardware virtualization of the
 * TSC functions properly. Similarly, the multiplier should be used in any TSC
 * emulation.
 *
 * See below for more details about the frequency multiplier.
 *
 *
 * (4) Guest running on a system it did not boot on ("base guest TSC")
 *
 * When a guest boots, its TSC offset is simply the negated host TSC at the time
 * it booted. If a guest is migrated from a source host to a target host, the
 * TSC offset from the source host is no longer useful for several reasons:
 * - the target host TSC has no relationship to the source host TSC
 * - the guest did not boot on the target system, so the TSC of the target host
 *   is not sufficient to describe how long the guest has been running prior to
 *   migration
 * - the target system may have a different TSC frequency than the source system
 *
 * Ignoring the issue of frequency differences for a moment, let's consider how
 * to re-align the guest TSC with the host TSC of the target host. Intuitively,
 * for the guest to see the correct TSC, we still want to add some offset to the
 * host TSC that offsets how long this guest has been running on
 * the system.
 *
 * An example here might be helpful. Consider a source host and target host,
 * both with TSC frequencies of 1GHz. On the source host, the guest and host TSC
 * values might look like:
 *
 *  +----------------------------------------------------------------------+
 *  | Event                 | source host TSC  | guest TSC                 |
 *  ------------------------------------------------------------------------
 *  | guest boot  (t=0s)    | 5000000000       | 5000000000 + -5000000000  |
 *  |                       |                  | 0                         |
 *  ------------------------------------------------------------------------
 *  | guest rdtsc (t=10s))  | 15000000000      | 15000000000 + -5000000000 |
 *  |                       |                  | 10000000000               |
 *  ------------------------------------------------------------------------
 *  | migration   (t=15s)   | 20000000000      | 20000000000 + -5000000000 |
 *  |                       |                  | 15000000000               |
 *  +----------------------------------------------------------------------+
 *
 * Ignoring the time it takes for a guest to physically migrate machines, on the
 * target host, we would expect the TSC to continue functioning as such:
 *
 *  +----------------------------------------------------------------------+
 *  | Event                 | target host TSC  | guest TSC                 |
 *  ------------------------------------------------------------------------
 *  | guest migrate (t=15s) | 300000000000     | 15000000000               |
 *  ------------------------------------------------------------------------
 *  | guest rdtsc (t=20s))  | 305000000000     | 20000000000               |
 *  ------------------------------------------------------------------------
 *
 * In order to produce a correct TSC value here, we can calculate a new
 * "effective" boot TSC that maps to what the host TSC would've been had it been
 * booted on the target. We add that to the guest TSC when it began to run on
 * this machine, and negate them both to get a new offset. In this example, the
 * effective boot TSC is: -(300000000000 - 15000000000) = -285000000000.
 *
 *  +-------------------------------------------------------------------------+
 *  | Event                 | target host TSC  | guest TSC                    |
 *  ---------------------------------------------------------------------------
 *  | guest "boot" (t=0s)   | 285000000000     | 285000000000 + -285000000000 |
 *  |                       |                  | 0                            |
 *  ---------------------------------------------------------------------------
 *  | guest migrate (t=15s) | 300000000000     | 300000000000 + -285000000000 |
 *  |                       |                  | 15000000000                  |
 *  ---------------------------------------------------------------------------
 *  | guest rdtsc (t=20s))  | 305000000000     | 305000000000 + -285000000000 |
 *  |                       |                  | 20000000000                  |
 *  --------------------------------------------------------------------------+
 *
 * To support the offset calculation following a migration, the VMM data time
 * interface allows callers to set a "base guest TSC", which is the TSC value of
 * the guest when it began running on the host. The current guest TSC can be
 * requested via a read of the time data. See below for details on that
 * interface.
 *
 * Frequency differences between the host and the guest are accounted for when
 * scaling the host TSC. See below for details on the frequency multiplier.
 *
 *
 * --------------------
 * TSC OFFSET SUMMARY
 * --------------------
 *
 * Factoring in all of the components to the TSC above, the TSC offset that is
 * programmed by the hypervisor before running a given vCPU is:
 *
 * offset = -((base host TSC, scaled if needed) - base_guest_tsc) + vCPU offset
 *
 * This offset is stored in two pieces. Per-vCPU offsets are stored with the
 * given vCPU and added in when programming the offset. The rest of the offset
 * is stored as a VM-wide offset, and computed either at boot or when the time
 * data is written to.
 *
 * It is safe to add the vCPU offset and the VM-wide offsets together because
 * the vCPU offset is in terms of the guest TSC. The host TSC is scaled before
 * using it in calculations, so all TSC values are applicable to the same
 * frequency.
 *
 * Note: Though both the VM-wide offset and per-vCPU offsets may be negative, we
 * store them as unsigned values and perform all offsetting math unsigned. This
 * is to avoid UB from signed overflow.
 *
 * -------------------------
 * TSC FREQUENCY MULTIPLIER
 * -------------------------
 *
 * In order to account for frequency differences between the host and guest, SVM
 * and VMX provide an interface to set a "frequency multiplier" (or "frequency
 * ratio") representing guest to host frequency. In a hardware-virtualized read
 * of the TSC, the host TSC is scaled using this multiplier prior to adding the
 * programmed TSC offset.
 *
 * Both platforms represent the ratio as a fixed point number, where the lower
 * bits are used as a fractional component, and some number of the upper bits
 * are used as the integer component.
 *
 * Some example multipliers, for a platform with FRAC fractional bits in the
 * multiplier:
 * - guest frequency == host: 1 << FRAC
 * - guest frequency is 2x host: 1 << (FRAC + 1)
 * - guest frequency is 0.5x host: 1 << (FRAC - 1), as the highest-order
 *   fractional bit represents 1/2
 * - guest frequency is 2.5x host: (1 << FRAC) | (1 << (FRAC - 1))
 * and so on.
 *
 * In general, the frequency multiplier is calculated as follows:
 *              (guest_hz * (1 << FRAC_SIZE)) / host_hz
 *
 * The multiplier should be used any time the host TSC value is used in
 * calculations with the guest TSC (and their frequencies differ). The function
 * `vmm_scale_tsc` is intended to be used for these purposes, as it will scale
 * the host TSC only if needed.
 *
 * The multiplier should also be programmed by the hypervisor before the guest
 * is run.
 *
 *
 * ----------------------------
 * DEVICE TIMERS (BOOT_HRTIME)
 * ----------------------------
 *
 * Emulated devices use timers to do things such as scheduling periodic events.
 * These timers are scheduled relative to the hrtime of the host. When device
 * state is exported or imported, we use boot_hrtime to normalize these timers
 * against the host hrtime. The boot_hrtime represents the hrtime of the host
 * when the guest was booted.
 *
 * If a guest is migrated to a different machine, boot_hrtime must be adjusted
 * to match the hrtime of when the guest was effectively booted on the target
 * host. This allows timers to continue functioning when device state is
 * imported on the target.
 *
 *
 * ------------------------
 * VMM DATA TIME INTERFACE
 * ------------------------
 *
 * In order to facilitate live migrations of guests, we provide an interface,
 * via the VMM data read/write ioctls, for userspace to make changes to the
 * guest's view of the TSC and device timers, allowing these features to
 * continue functioning after a migration.
 *
 * The interface was designed to expose the minimal amount of data needed for a
 * userspace component to make adjustments to the guest's view of time (e.g., to
 * account for time passing in a live migration). At a minimum, such a program
 * needs:
 * - the current guest TSC
 * - guest TSC frequency
 * - guest's boot_hrtime
 * - timestamps of when this data was taken (hrtime for hrtime calculations, and
 *   wall clock time for computing time deltas between machines)
 *
 * The wall clock time is provided for consumers to make adjustments to the
 * guest TSC and boot_hrtime based on deltas observed during migrations. It may
 * be prudent for consumers to use this data only in circumstances where the
 * source and target have well-synchronized wall clocks, but nothing in the
 * interface depends on this assumption.
 *
 * On writes, consumers write back:
 * - the base guest TSC (used for TSC offset calculations)
 * - desired boot_hrtime
 * - guest_frequency (cannot change)
 * - hrtime of when this data was adjusted
 * - (wall clock time on writes is ignored)
 *
 * The interface will adjust the input guest TSC slightly, based on the input
 * hrtime, to account for latency between userspace calculations and application
 * of the data on the kernel side. This amounts to adding a small amount of
 * additional "uptime" for the guest.
 *
 * After the adjustments, the interface updates the VM-wide TSC offset and
 * boot_hrtime. Per-vCPU offsets are not adjusted, as those are already in terms
 * of the guest TSC and can be exported/imported via the MSR VMM data interface.
 *
 *
 * --------------------------------
 * SUPPORTED PLATFORMS AND CAVEATS
 * --------------------------------
 *
 * While both VMX and SVM offer TSC scaling as a feature, at this time only SVM
 * is supported by bhyve.
 *
 * The time data interface is designed such that Intel support can be added
 * easily, and all other aspects of the time interface should work on Intel.
 * (Without frequency control though, in practice, doing live migrations of
 * guests on Intel will not work for time-related things, as two machines
 * rarely have exactly the same frequency).
 *
 * Additionally, while on both SVM and VMX the frequency multiplier is a fixed
 * point number, each uses a different number of fractional and integer bits for
 * the multiplier. As such, calculating the multiplier and fractional bit size
 * is requested via the vmm_ops.
 *
 * Care should be taken to set reasonable limits for ratios based on the
 * platform, as the difference in fractional bits can lead to slightly different
 * tradeoffs in terms of representable ratios and potentially overflowing
 * calculations.
 */

/*
 * Scales the TSC if needed, based on the input frequency multiplier.
 */
static uint64_t
vmm_scale_tsc(uint64_t tsc, uint64_t mult)
{
        const uint32_t frac_size = ops->fr_fracsize;

        if (mult != VM_TSCM_NOSCALE) {
                VERIFY3U(frac_size, >, 0);
                return (scale_tsc(tsc, mult, frac_size));
        } else {
                return (tsc);
        }
}

/*
 * Calculate the frequency multiplier, which represents the ratio of
 * guest_hz / host_hz. The frequency multiplier is a fixed point number with
 * `frac_sz` fractional bits (fractional bits begin at bit 0).
 *
 * See comment for "calc_freq_multiplier" in "vmm_time_support.S" for more
 * information about valid input to this function.
 */
uint64_t
vmm_calc_freq_multiplier(uint64_t guest_hz, uint64_t host_hz,
    uint32_t frac_size)
{
        VERIFY3U(guest_hz, !=, 0);
        VERIFY3U(frac_size, >, 0);
        VERIFY3U(frac_size, <, 64);

        return (calc_freq_multiplier(guest_hz, host_hz, frac_size));
}

/*
 * Calculate the guest VM-wide TSC offset.
 *
 * offset = - ((base host TSC, scaled if needed) - base_guest_tsc)
 *
 * The base_host_tsc and the base_guest_tsc are the TSC values of the host
 * (read on the system) and the guest (calculated) at the same point in time.
 * This allows us to fix the guest TSC at this point in time as a base, either
 * following boot (guest TSC = 0), or a change to the guest's time data from
 * userspace (such as in the case of a migration).
 */
static uint64_t
calc_tsc_offset(uint64_t base_host_tsc, uint64_t base_guest_tsc, uint64_t mult)
{
        const uint64_t htsc_scaled = vmm_scale_tsc(base_host_tsc, mult);
        if (htsc_scaled > base_guest_tsc) {
                return ((uint64_t)(- (int64_t)(htsc_scaled - base_guest_tsc)));
        } else {
                return (base_guest_tsc - htsc_scaled);
        }
}

/*
 * Calculate an estimate of the guest TSC.
 *
 * guest_tsc = (host TSC, scaled if needed) + offset
 */
static uint64_t
calc_guest_tsc(uint64_t host_tsc, uint64_t mult, uint64_t offset)
{
        return (vmm_scale_tsc(host_tsc, mult) + offset);
}

/*
 * Take a non-atomic "snapshot" of the current:
 * - TSC
 * - hrtime
 * - wall clock time
 */
static void
vmm_time_snapshot(uint64_t *tsc, hrtime_t *hrtime, timespec_t *hrestime)
{
        /*
         * Disable interrupts while we take the readings: In the absence of a
         * mechanism to convert hrtime to hrestime, we want the time between
         * each of these measurements to be as small as possible.
         */
        ulong_t iflag = intr_clear();

        hrtime_t hrt = gethrtimeunscaledf();
        *tsc = (uint64_t)hrt;
        *hrtime = hrt;
        scalehrtime(hrtime);
        gethrestime(hrestime);

        intr_restore(iflag);
}

/*
 * Read VMM Time data
 *
 * Provides:
 * - the current guest TSC and TSC frequency
 * - guest boot_hrtime
 * - timestamps of the read (hrtime and wall clock time)
 */
static int
vmm_data_read_vmm_time(void *arg, const vmm_data_req_t *req)
{
        VERIFY3U(req->vdr_class, ==, VDC_VMM_TIME);
        VERIFY3U(req->vdr_version, ==, 1);
        VERIFY3U(req->vdr_len, >=, sizeof (struct vdi_time_info_v1));

        struct vm *vm = arg;
        struct vdi_time_info_v1 *out = req->vdr_data;

        /*
         * Since write operations on VMM_TIME data are strict about vcpuid
         * (see: vmm_data_write_vmm_time()), read operations should be as well.
         */
        if (req->vdr_vcpuid != -1) {
                return (EINVAL);
        }

        /* Take a snapshot of this point in time */
        uint64_t tsc;
        hrtime_t hrtime;
        timespec_t hrestime;
        vmm_time_snapshot(&tsc, &hrtime, &hrestime);

        /* Write the output values */
        out->vt_guest_freq = vm->guest_freq;

        /*
         * Use only the VM-wide TSC offset for calculating the guest TSC,
         * ignoring per-vCPU offsets. This value is provided as a "base" guest
         * TSC at the time of the read; per-vCPU offsets are factored in as
         * needed elsewhere, either when running the vCPU or if the guest reads
         * the TSC via rdmsr.
         */
        out->vt_guest_tsc = calc_guest_tsc(tsc, vm->freq_multiplier,
            vm->tsc_offset);
        out->vt_boot_hrtime = vm->boot_hrtime;
        out->vt_hrtime = hrtime;
        out->vt_hres_sec = hrestime.tv_sec;
        out->vt_hres_ns = hrestime.tv_nsec;

        return (0);
}

/*
 * Modify VMM Time data related values
 *
 * This interface serves to allow guests' TSC and device timers to continue
 * functioning across live migrations. On a successful write, the VM-wide TSC
 * offset and boot_hrtime of the guest are updated.
 *
 * The interface requires an hrtime of the system at which the caller wrote
 * this data; this allows us to adjust the TSC and boot_hrtime slightly to
 * account for time passing between the userspace call and application
 * of the data here.
 *
 * There are several possibilities for invalid input, including:
 * - a requested guest frequency of 0, or a frequency otherwise unsupported by
 *   the underlying platform
 * - hrtime or boot_hrtime values that appear to be from the future
 * - the requested frequency does not match the host, and this system does not
 *   have hardware TSC scaling support
 */
static int
vmm_data_write_vmm_time(void *arg, const vmm_data_req_t *req)
{
        VERIFY3U(req->vdr_class, ==, VDC_VMM_TIME);
        VERIFY3U(req->vdr_version, ==, 1);
        VERIFY3U(req->vdr_len, >=, sizeof (struct vdi_time_info_v1));

        struct vm *vm = arg;
        const struct vdi_time_info_v1 *src = req->vdr_data;

        /*
         * While vcpuid values != -1 are tolerated by the vmm_data machinery for
         * VM-wide endpoints, the time-related data is more strict: It relies on
         * write-locking the VM (implied by the vcpuid -1) to prevent vCPUs or
         * other bits from observing inconsistent values while the state is
         * being written.
         */
        if (req->vdr_vcpuid != -1) {
                return (EINVAL);
        }

        /*
         * Platform-specific checks will verify the requested frequency against
         * the supported range further, but a frequency of 0 is never valid.
         */
        if (src->vt_guest_freq == 0) {
                return (EINVAL);
        }

        /*
         * Check whether the request frequency is supported and get the
         * frequency multiplier.
         */
        uint64_t mult = VM_TSCM_NOSCALE;
        freqratio_res_t res = ops->vmfreqratio(src->vt_guest_freq,
            vmm_host_freq, &mult);
        switch (res) {
        case FR_SCALING_NOT_SUPPORTED:
                /*
                 * This system doesn't support TSC scaling, and the guest/host
                 * frequencies differ
                 */
                return (EPERM);
        case FR_OUT_OF_RANGE:
                /* Requested frequency ratio is too small/large */
                return (EINVAL);
        case FR_SCALING_NOT_NEEDED:
                /* Host and guest frequencies are the same */
                VERIFY3U(mult, ==, VM_TSCM_NOSCALE);
                break;
        case FR_VALID:
                VERIFY3U(mult, !=, VM_TSCM_NOSCALE);
                break;
        }

        /*
         * Find (and validate) the hrtime delta between the input request and
         * when we received it so that we can bump the TSC to account for time
         * passing.
         *
         * We ignore the hrestime as input, as this is a field that
         * exists for reads.
         */
        uint64_t tsc;
        hrtime_t hrtime;
        timespec_t hrestime;
        vmm_time_snapshot(&tsc, &hrtime, &hrestime);
        if ((src->vt_hrtime > hrtime) || (src->vt_boot_hrtime > hrtime)) {
                /*
                 * The caller has passed in an hrtime / boot_hrtime from the
                 * future.
                 */
                return (EINVAL);
        }
        hrtime_t hrt_delta = hrtime - src->vt_hrtime;

        /* Calculate guest TSC adjustment */
        const uint64_t host_ticks = unscalehrtime(hrt_delta);
        const uint64_t guest_ticks = vmm_scale_tsc(host_ticks,
            vm->freq_multiplier);
        const uint64_t base_guest_tsc = src->vt_guest_tsc + guest_ticks;

        /* Update guest time data */
        vm->freq_multiplier = mult;
        vm->guest_freq = src->vt_guest_freq;
        vm->boot_hrtime = src->vt_boot_hrtime;
        vm->tsc_offset = calc_tsc_offset(tsc, base_guest_tsc,
            vm->freq_multiplier);

        return (0);
}

static const vmm_data_version_entry_t vmm_time_v1 = {
        .vdve_class = VDC_VMM_TIME,
        .vdve_version = 1,
        .vdve_len_expect = sizeof (struct vdi_time_info_v1),
        .vdve_readf = vmm_data_read_vmm_time,
        .vdve_writef = vmm_data_write_vmm_time,
};
VMM_DATA_VERSION(vmm_time_v1);


static int
vmm_data_read_versions(void *arg, const vmm_data_req_t *req)
{
        VERIFY3U(req->vdr_class, ==, VDC_VERSION);
        VERIFY3U(req->vdr_version, ==, 1);

        const uint32_t total_size = SET_COUNT(vmm_data_version_entries) *
            sizeof (struct vdi_version_entry_v1);

        /* Make sure there is room for all of the entries */
        *req->vdr_result_len = total_size;
        if (req->vdr_len < *req->vdr_result_len) {
                return (ENOSPC);
        }

        struct vdi_version_entry_v1 *entryp = req->vdr_data;
        const vmm_data_version_entry_t **vdpp;
        SET_FOREACH(vdpp, vmm_data_version_entries) {
                const vmm_data_version_entry_t *vdp = *vdpp;

                entryp->vve_class = vdp->vdve_class;
                entryp->vve_version = vdp->vdve_version;
                entryp->vve_len_expect = vdp->vdve_len_expect;
                entryp->vve_len_per_item = vdp->vdve_len_per_item;
                entryp++;
        }
        return (0);
}

static int
vmm_data_write_versions(void *arg, const vmm_data_req_t *req)
{
        /* Writing to the version information makes no sense */
        return (EPERM);
}

static const vmm_data_version_entry_t versions_v1 = {
        .vdve_class = VDC_VERSION,
        .vdve_version = 1,
        .vdve_len_per_item = sizeof (struct vdi_version_entry_v1),
        .vdve_readf = vmm_data_read_versions,
        .vdve_writef = vmm_data_write_versions,
};
VMM_DATA_VERSION(versions_v1);

int
vmm_data_read(struct vm *vm, const vmm_data_req_t *req)
{
        int err = 0;

        const vmm_data_version_entry_t *entry = NULL;
        err = vmm_data_find(req, &entry);
        if (err != 0) {
                return (err);
        }
        ASSERT(entry != NULL);

        if (entry->vdve_readf != NULL) {
                void *datap = vmm_data_from_class(req, vm);

                err = entry->vdve_readf(datap, req);
        } else if (entry->vdve_vcpu_readf != NULL) {
                err = entry->vdve_vcpu_readf(vm, req->vdr_vcpuid, req);
        } else {
                err = EINVAL;
        }

        /*
         * Successful reads of fixed-length data should populate the length of
         * that result.
         */
        if (err == 0 && entry->vdve_len_expect != 0) {
                *req->vdr_result_len = entry->vdve_len_expect;
        }

        return (err);
}

int
vmm_data_write(struct vm *vm, const vmm_data_req_t *req)
{
        int err = 0;

        const vmm_data_version_entry_t *entry = NULL;
        err = vmm_data_find(req, &entry);
        if (err != 0) {
                return (err);
        }
        ASSERT(entry != NULL);

        if (entry->vdve_writef != NULL) {
                void *datap = vmm_data_from_class(req, vm);

                err = entry->vdve_writef(datap, req);
        } else if (entry->vdve_vcpu_writef != NULL) {
                err = entry->vdve_vcpu_writef(vm, req->vdr_vcpuid, req);
        } else {
                err = EINVAL;
        }

        /*
         * Successful writes of fixed-length data should populate the length of
         * that result.
         */
        if (err == 0 && entry->vdve_len_expect != 0) {
                *req->vdr_result_len = entry->vdve_len_expect;
        }

        return (err);
}

static void
vm_mmiohook_init(struct vm *vm, struct mmiohook_config *mh)
{
        VERIFY3P(mh->mhc_entries, ==, NULL);
        VERIFY0(mh->mhc_count);
}

static void
vm_mmiohook_cleanup(struct vm *vm, struct mmiohook_config *mh)
{
        if (mh->mhc_count == 0)
                return;

        kmem_free(mh->mhc_entries, sizeof (mmiohook_entry_t) * mh->mhc_count);
        mh->mhc_entries = NULL;
        mh->mhc_count = 0;
}

int
vm_mmio_hook(struct vm *vm, uint64_t address, uint32_t size,
    mmio_handler_t func, void *arg, void **cookiep)
{
        struct mmiohook_config *mh = &vm->mmiohooks;
        mmiohook_entry_t *old_ents = mh->mhc_entries;
        uint_t old_count = mh->mhc_count;
        mmiohook_entry_t *ents;
        uint_t count = old_count + 1;
        const uint64_t end = address + size;
        const size_t esz = sizeof (mmiohook_entry_t);

        if (size == 0 || end < address)
                return (EINVAL);

        if (old_count >= mmiohook_entry_limit)
                return (ENOSPC);

        for (uint_t i = 0; i < old_count; i++) {
                mmiohook_entry_t *e = &old_ents[i];
                const uint64_t old_end = e->mhe_addr + e->mhe_size;

                if (address < old_end && e->mhe_addr < end)
                        return (EEXIST);
        }

        ents = kmem_alloc(count * esz, KM_SLEEP);
        if (old_count > 0)
                bcopy(old_ents, ents, old_count * esz);

        mmiohook_entry_t *ne = &ents[old_count];

        ne->mhe_func = func;
        ne->mhe_arg = arg;
        ne->mhe_addr = address;
        ne->mhe_size = size;
        /*
         * Since we don't allow any overlapping hooks, the address can be used
         * for the cookie.
         */
        *cookiep = (void *)(uintptr_t)ne->mhe_addr;

        mh->mhc_entries = ents;
        mh->mhc_count = count;

        if (old_count > 0)
                kmem_free(old_ents, old_count * esz);

        return (0);
}

int
vm_mmio_unhook(struct vm *vm, void **cookie)
{
        struct mmiohook_config *mh = &vm->mmiohooks;
        mmiohook_entry_t *old_ents = mh->mhc_entries;
        uint_t old_count = mh->mhc_count;
        const size_t esz = sizeof (mmiohook_entry_t);
        mmiohook_entry_t *ents;
        uint_t i;

        for (i = 0; i < old_count; i++) {
                mmiohook_entry_t *e = &old_ents[i];

                if (e->mhe_addr == (uint64_t)(uintptr_t)*cookie)
                        break;
        }

        if (i >= old_count)
                return (ENOENT);

        if (old_count == 1) {
                mh->mhc_entries = NULL;
                mh->mhc_count = 0;
        } else {
                uint_t count = old_count - 1;

                ents = kmem_alloc(count * esz, KM_SLEEP);
                if (i > 0)
                        bcopy(old_ents, ents, esz * i);
                if (i < count)
                        bcopy(old_ents + i + 1, ents + i, (count - i) * esz);

                mh->mhc_entries = ents;
                mh->mhc_count = count;
        }
        kmem_free(old_ents, old_count * esz);
        *cookie = NULL;

        return (0);
}