/*-
 * 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.
 *
 * Copyright 2015 Pluribus Networks Inc.
 * Copyright 2018 Joyent, Inc.
 * Copyright 2022 Oxide Computer Company
 * Copyright 2022 OmniOS Community Edition (OmniOSce) Association.
 */

#include <sys/types.h>

#ifndef __FreeBSD__
#include <sys/cpuset.h>
#include <intel/vmcs.h>
#endif

#include <machine/atomic.h>

#ifndef WITHOUT_CAPSICUM
#include <capsicum_helpers.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <err.h>
#include <errno.h>
#include <libgen.h>
#include <unistd.h>
#include <assert.h>
#include <pthread.h>
#include <pthread_np.h>
#include <sysexits.h>
#include <stdbool.h>
#include <stdint.h>

#include <machine/vmm.h>
#include <vmmapi.h>

#include "bhyverun.h"
#include "config.h"
#include "debug.h"
#include "gdb.h"
#include "inout.h"
#include "mem.h"
#include "spinup_ap.h"
#include "vmexit.h"
#include "xmsr.h"

#ifndef __FreeBSD__
static struct vm_entry *vmentry;

int
vmentry_init(int ncpus)
{
        vmentry = calloc(ncpus, sizeof(*vmentry));
        return (vmentry == NULL ? -1 : 0);
}

struct vm_entry *
vmentry_vcpu(int vcpuid)
{
        return (&vmentry[vcpuid]);
}

static void
vmentry_mmio_read(struct vcpu *vcpu, uint64_t gpa, uint8_t bytes, uint64_t data)
{
        struct vm_entry *entry = &vmentry[vcpu_id(vcpu)];
        struct vm_mmio *mmio = &entry->u.mmio;

        assert(entry->cmd == VEC_DEFAULT);

        entry->cmd = VEC_FULFILL_MMIO;
        mmio->bytes = bytes;
        mmio->read = 1;
        mmio->gpa = gpa;
        mmio->data = data;
}

static void
vmentry_mmio_write(struct vcpu *vcpu, uint64_t gpa, uint8_t bytes)
{
        struct vm_entry *entry = &vmentry[vcpu_id(vcpu)];
        struct vm_mmio *mmio = &entry->u.mmio;

        assert(entry->cmd == VEC_DEFAULT);

        entry->cmd = VEC_FULFILL_MMIO;
        mmio->bytes = bytes;
        mmio->read = 0;
        mmio->gpa = gpa;
        mmio->data = 0;
}

static void
vmentry_inout_read(struct vcpu *vcpu, uint16_t port, uint8_t bytes,
    uint32_t data)
{
        struct vm_entry *entry = &vmentry[vcpu_id(vcpu)];
        struct vm_inout *inout = &entry->u.inout;

        assert(entry->cmd == VEC_DEFAULT);

        entry->cmd = VEC_FULFILL_INOUT;
        inout->bytes = bytes;
        inout->flags = INOUT_IN;
        inout->port = port;
        inout->eax = data;
}

static void
vmentry_inout_write(struct vcpu *vcpu, uint16_t port, uint8_t bytes)
{
        struct vm_entry *entry = &vmentry[vcpu_id(vcpu)];
        struct vm_inout *inout = &entry->u.inout;

        assert(entry->cmd == VEC_DEFAULT);

        entry->cmd = VEC_FULFILL_INOUT;
        inout->bytes = bytes;
        inout->flags = 0;
        inout->port = port;
        inout->eax = 0;
}
#endif

#ifdef  __FreeBSD__
void
vm_inject_fault(struct vcpu *vcpu, int vector, int errcode_valid,
    int errcode)
{
        int error, restart_instruction;

        restart_instruction = 1;

        error = vm_inject_exception(vcpu, vector, errcode_valid, errcode,
            restart_instruction);
        assert(error == 0);
}
#endif

static int
vmexit_inout(struct vmctx *ctx, struct vcpu *vcpu, struct vm_exit *vme)
{
        int error;
        struct vm_inout inout;
        bool in;
        uint8_t bytes;

        inout = vme->u.inout;
        in = (inout.flags & INOUT_IN) != 0;
        bytes = inout.bytes;

        error = emulate_inout(ctx, vcpu, &inout);
        if (error) {
                EPRINTLN("Unhandled %s%c 0x%04x at 0x%lx",
                    in ? "in" : "out",
                    bytes == 1 ? 'b' : (bytes == 2 ? 'w' : 'l'),
                    inout.port, vme->rip);
                return (VMEXIT_ABORT);
        } else {
                /*
                 * Communicate the status of the inout operation back to the
                 * in-kernel instruction emulation.
                 */
                if (in) {
                        vmentry_inout_read(vcpu, inout.port, bytes, inout.eax);
                } else {
                        vmentry_inout_write(vcpu, inout.port, bytes);
                }
                return (VMEXIT_CONTINUE);
        }
}

static int
vmexit_rdmsr(struct vmctx *ctx __unused, struct vcpu *vcpu, struct vm_exit *vme)
{
        uint64_t val;
        uint32_t eax, edx;
        int error;

        val = 0;
        error = emulate_rdmsr(vcpu, vme->u.msr.code, &val);
        if (error != 0) {
                EPRINTLN("rdmsr to register %#x on vcpu %d",
                    vme->u.msr.code, vcpu_id(vcpu));
                if (get_config_bool("x86.strictmsr")) {
                        vm_inject_gp(vcpu);
                        return (VMEXIT_CONTINUE);
                }
        }

        eax = val;
        error = vm_set_register(vcpu, VM_REG_GUEST_RAX, eax);
        assert(error == 0);

        edx = val >> 32;
        error = vm_set_register(vcpu, VM_REG_GUEST_RDX, edx);
        assert(error == 0);

        return (VMEXIT_CONTINUE);
}

static int
vmexit_wrmsr(struct vmctx *ctx __unused, struct vcpu *vcpu, struct vm_exit *vme)
{
        int error;

        error = emulate_wrmsr(vcpu, vme->u.msr.code, vme->u.msr.wval);
        if (error != 0) {
                EPRINTLN("wrmsr to register %#x(%#lx) on vcpu %d",
                    vme->u.msr.code, vme->u.msr.wval, vcpu_id(vcpu));
                if (get_config_bool("x86.strictmsr")) {
                        vm_inject_gp(vcpu);
                        return (VMEXIT_CONTINUE);
                }
        }
        return (VMEXIT_CONTINUE);
}

static const char * const vmx_exit_reason_desc[] = {
        [EXIT_REASON_EXCEPTION] = "Exception or non-maskable interrupt (NMI)",
        [EXIT_REASON_EXT_INTR] = "External interrupt",
        [EXIT_REASON_TRIPLE_FAULT] = "Triple fault",
        [EXIT_REASON_INIT] = "INIT signal",
        [EXIT_REASON_SIPI] = "Start-up IPI (SIPI)",
        [EXIT_REASON_IO_SMI] = "I/O system-management interrupt (SMI)",
        [EXIT_REASON_SMI] = "Other SMI",
        [EXIT_REASON_INTR_WINDOW] = "Interrupt window",
        [EXIT_REASON_NMI_WINDOW] = "NMI window",
        [EXIT_REASON_TASK_SWITCH] = "Task switch",
        [EXIT_REASON_CPUID] = "CPUID",
        [EXIT_REASON_GETSEC] = "GETSEC",
        [EXIT_REASON_HLT] = "HLT",
        [EXIT_REASON_INVD] = "INVD",
        [EXIT_REASON_INVLPG] = "INVLPG",
        [EXIT_REASON_RDPMC] = "RDPMC",
        [EXIT_REASON_RDTSC] = "RDTSC",
        [EXIT_REASON_RSM] = "RSM",
        [EXIT_REASON_VMCALL] = "VMCALL",
        [EXIT_REASON_VMCLEAR] = "VMCLEAR",
        [EXIT_REASON_VMLAUNCH] = "VMLAUNCH",
        [EXIT_REASON_VMPTRLD] = "VMPTRLD",
        [EXIT_REASON_VMPTRST] = "VMPTRST",
        [EXIT_REASON_VMREAD] = "VMREAD",
        [EXIT_REASON_VMRESUME] = "VMRESUME",
        [EXIT_REASON_VMWRITE] = "VMWRITE",
        [EXIT_REASON_VMXOFF] = "VMXOFF",
        [EXIT_REASON_VMXON] = "VMXON",
        [EXIT_REASON_CR_ACCESS] = "Control-register accesses",
        [EXIT_REASON_DR_ACCESS] = "MOV DR",
        [EXIT_REASON_INOUT] = "I/O instruction",
        [EXIT_REASON_RDMSR] = "RDMSR",
        [EXIT_REASON_WRMSR] = "WRMSR",
        [EXIT_REASON_INVAL_VMCS] =
            "VM-entry failure due to invalid guest state",
        [EXIT_REASON_INVAL_MSR] = "VM-entry failure due to MSR loading",
        [EXIT_REASON_MWAIT] = "MWAIT",
        [EXIT_REASON_MTF] = "Monitor trap flag",
        [EXIT_REASON_MONITOR] = "MONITOR",
        [EXIT_REASON_PAUSE] = "PAUSE",
        [EXIT_REASON_MCE_DURING_ENTRY] =
            "VM-entry failure due to machine-check event",
        [EXIT_REASON_TPR] = "TPR below threshold",
        [EXIT_REASON_APIC_ACCESS] = "APIC access",
        [EXIT_REASON_VIRTUALIZED_EOI] = "Virtualized EOI",
        [EXIT_REASON_GDTR_IDTR] = "Access to GDTR or IDTR",
        [EXIT_REASON_LDTR_TR] = "Access to LDTR or TR",
        [EXIT_REASON_EPT_FAULT] = "EPT violation",
        [EXIT_REASON_EPT_MISCONFIG] = "EPT misconfiguration",
        [EXIT_REASON_INVEPT] = "INVEPT",
        [EXIT_REASON_RDTSCP] = "RDTSCP",
        [EXIT_REASON_VMX_PREEMPT] = "VMX-preemption timer expired",
        [EXIT_REASON_INVVPID] = "INVVPID",
        [EXIT_REASON_WBINVD] = "WBINVD",
        [EXIT_REASON_XSETBV] = "XSETBV",
        [EXIT_REASON_APIC_WRITE] = "APIC write",
        [EXIT_REASON_RDRAND] = "RDRAND",
        [EXIT_REASON_INVPCID] = "INVPCID",
        [EXIT_REASON_VMFUNC] = "VMFUNC",
        [EXIT_REASON_ENCLS] = "ENCLS",
        [EXIT_REASON_RDSEED] = "RDSEED",
        [EXIT_REASON_PM_LOG_FULL] = "Page-modification log full",
        [EXIT_REASON_XSAVES] = "XSAVES",
        [EXIT_REASON_XRSTORS] = "XRSTORS"
};

#ifndef __FreeBSD__
static int
vmexit_run_state(struct vmctx *ctx __unused, struct vcpu *vcpu __unused,
    struct vm_exit *vme __unused)
{
        /*
         * Run-state transitions (INIT, SIPI, etc) are handled in-kernel, so an
         * exit to userspace with that code is not expected.
         */
        fprintf(stderr, "unexpected run-state VM exit");
        return (VMEXIT_ABORT);
}

static int
vmexit_paging(struct vmctx *ctx __unused, struct vcpu *vcpu,
    struct vm_exit *vme)
{
        fprintf(stderr, "vm exit[%d]\n", vcpu_id(vcpu));
        fprintf(stderr, "\treason\t\tPAGING\n");
        fprintf(stderr, "\trip\t\t0x%016lx\n", vme->rip);
        fprintf(stderr, "\tgpa\t\t0x%016lx\n", vme->u.paging.gpa);
        fprintf(stderr, "\tfault_type\t\t%d\n", vme->u.paging.fault_type);

        return (VMEXIT_ABORT);
}
#endif /* __FreeBSD__ */

#ifdef __FreeBSD__
#define DEBUG_EPT_MISCONFIG
#else
/* EPT misconfig debugging not possible now that raw VMCS access is gone */
#endif

#ifdef DEBUG_EPT_MISCONFIG
#define VMCS_GUEST_PHYSICAL_ADDRESS     0x00002400

static uint64_t ept_misconfig_gpa, ept_misconfig_pte[4];
static int ept_misconfig_ptenum;
#endif

static const char *
vmexit_vmx_desc(uint32_t exit_reason)
{

        if (exit_reason >= nitems(vmx_exit_reason_desc) ||
            vmx_exit_reason_desc[exit_reason] == NULL)
                return ("Unknown");
        return (vmx_exit_reason_desc[exit_reason]);
}

static int
vmexit_vmx(struct vmctx *ctx, struct vcpu *vcpu, struct vm_exit *vme)
{

        EPRINTLN("vm exit[%d]", vcpu_id(vcpu));
        EPRINTLN("\treason\t\tVMX");
        EPRINTLN("\trip\t\t0x%016lx", vme->rip);
        EPRINTLN("\tinst_length\t%d", vme->inst_length);
        EPRINTLN("\tstatus\t\t%d", vme->u.vmx.status);
        EPRINTLN("\texit_reason\t%u (%s)", vme->u.vmx.exit_reason,
            vmexit_vmx_desc(vme->u.vmx.exit_reason));
        EPRINTLN("\tqualification\t0x%016lx",
            vme->u.vmx.exit_qualification);
        EPRINTLN("\tinst_type\t\t%d", vme->u.vmx.inst_type);
        EPRINTLN("\tinst_error\t\t%d", vme->u.vmx.inst_error);
#ifdef DEBUG_EPT_MISCONFIG
        if (vme->u.vmx.exit_reason == EXIT_REASON_EPT_MISCONFIG) {
                vm_get_register(vcpu,
                    VMCS_IDENT(VMCS_GUEST_PHYSICAL_ADDRESS),
                    &ept_misconfig_gpa);
                vm_get_gpa_pmap(ctx, ept_misconfig_gpa, ept_misconfig_pte,
                    &ept_misconfig_ptenum);
                EPRINTLN("\tEPT misconfiguration:");
                EPRINTLN("\t\tGPA: %#lx", ept_misconfig_gpa);
                EPRINTLN("\t\tPTE(%d): %#lx %#lx %#lx %#lx",
                    ept_misconfig_ptenum, ept_misconfig_pte[0],
                    ept_misconfig_pte[1], ept_misconfig_pte[2],
                    ept_misconfig_pte[3]);
        }
#endif  /* DEBUG_EPT_MISCONFIG */
        return (VMEXIT_ABORT);
}

static int
vmexit_svm(struct vmctx *ctx __unused, struct vcpu *vcpu, struct vm_exit *vme)
{
        EPRINTLN("vm exit[%d]", vcpu_id(vcpu));
        EPRINTLN("\treason\t\tSVM");
        EPRINTLN("\trip\t\t0x%016lx", vme->rip);
        EPRINTLN("\tinst_length\t%d", vme->inst_length);
        EPRINTLN("\texitcode\t%#lx", vme->u.svm.exitcode);
        EPRINTLN("\texitinfo1\t%#lx", vme->u.svm.exitinfo1);
        EPRINTLN("\texitinfo2\t%#lx", vme->u.svm.exitinfo2);
        return (VMEXIT_ABORT);
}

static int
vmexit_bogus(struct vmctx *ctx __unused, struct vcpu *vcpu __unused,
    struct vm_exit *vme)
{

        assert(vme->inst_length == 0);

        return (VMEXIT_CONTINUE);
}

static int
vmexit_hlt(struct vmctx *ctx __unused, struct vcpu *vcpu __unused,
    struct vm_exit *vme __unused)
{

        /*
         * Just continue execution with the next instruction. We use
         * the HLT VM exit as a way to be friendly with the host
         * scheduler.
         */
        return (VMEXIT_CONTINUE);
}

static int
vmexit_pause(struct vmctx *ctx __unused, struct vcpu *vcpu __unused,
    struct vm_exit *vme __unused)
{
        return (VMEXIT_CONTINUE);
}

static int
vmexit_mtrap(struct vmctx *ctx __unused, struct vcpu *vcpu, struct vm_exit *vme)
{

        assert(vme->inst_length == 0);

        gdb_cpu_mtrap(vcpu);

        return (VMEXIT_CONTINUE);
}

static int
vmexit_inst_emul(struct vmctx *ctx __unused, struct vcpu *vcpu,
    struct vm_exit *vme)
{
        uint8_t i, valid;

        fprintf(stderr, "Failed to emulate instruction sequence ");

        valid = vme->u.inst_emul.num_valid;
        if (valid != 0) {
                assert(valid <= sizeof (vme->u.inst_emul.inst));
                fprintf(stderr, "[");
                for (i = 0; i < valid; i++) {
                        if (i == 0) {
                                fprintf(stderr, "%02x",
                                    vme->u.inst_emul.inst[i]);
                        } else {
                                fprintf(stderr, ", %02x",
                                    vme->u.inst_emul.inst[i]);
                        }
                }
                fprintf(stderr, "] ");
        }
        fprintf(stderr, "@ %rip = %x\n", vme->rip);

        return (VMEXIT_ABORT);
}

#ifndef __FreeBSD__
static int
vmexit_mmio(struct vmctx *ctx __unused, struct vcpu *vcpu, struct vm_exit *vme)
{
        int err;
        struct vm_mmio mmio;
        bool is_read;

        mmio = vme->u.mmio;
        is_read = (mmio.read != 0);

        err = emulate_mem(vcpu, &mmio);

        if (err == ESRCH) {
                fprintf(stderr, "Unhandled memory access to 0x%lx\n", mmio.gpa);

                /*
                 * Access to non-existent physical addresses is not likely to
                 * result in fatal errors on hardware machines, but rather reads
                 * of all-ones or discarded-but-acknowledged writes.
                 */
                mmio.data = ~0UL;
                err = 0;
        }

        if (err == 0) {
                if (is_read) {
                        vmentry_mmio_read(vcpu, mmio.gpa, mmio.bytes,
                            mmio.data);
                } else {
                        vmentry_mmio_write(vcpu, mmio.gpa, mmio.bytes);
                }
                return (VMEXIT_CONTINUE);
        }

        fprintf(stderr, "Unhandled mmio error to 0x%lx: %d\n", mmio.gpa, err);
        return (VMEXIT_ABORT);
}
#endif /* !__FreeBSD__ */

static int
vmexit_suspend(struct vmctx *ctx, struct vcpu *vcpu, struct vm_exit *vme)
{
        enum vm_suspend_how how;
        int vcpuid = vcpu_id(vcpu);

        how = vme->u.suspended.how;

        fbsdrun_deletecpu(vcpuid);

        switch (how) {
        case VM_SUSPEND_RESET:
                exit(0);
        case VM_SUSPEND_POWEROFF:
                if (get_config_bool_default("destroy_on_poweroff", false))
                        vm_destroy(ctx);
                exit(1);
        case VM_SUSPEND_HALT:
                exit(2);
        case VM_SUSPEND_TRIPLEFAULT:
                exit(3);
        default:
                EPRINTLN("vmexit_suspend: invalid reason %d", how);
                exit(100);
        }
        return (0);     /* NOTREACHED */
}

static int
vmexit_debug(struct vmctx *ctx __unused, struct vcpu *vcpu,
    struct vm_exit *vme __unused)
{
        gdb_cpu_suspend(vcpu);
        /*
         * Sleep for a short period to avoid chewing up the CPU in the
         * window between activation of the vCPU thread and the STARTUP IPI.
         */
        usleep(1000);
        return (VMEXIT_CONTINUE);
}

static int
vmexit_breakpoint(struct vmctx *ctx __unused, struct vcpu *vcpu,
    struct vm_exit *vme)
{

        gdb_cpu_breakpoint(vcpu, vme);
        return (VMEXIT_CONTINUE);
}

#ifdef  __FreeBSD__
static int
vmexit_ipi(struct vmctx *ctx __unused, struct vcpu *vcpu __unused,
    struct vm_exit *vme)
{
        int error = -1;
        int i;
        switch (vme->u.ipi.mode) {
        case APIC_DELMODE_INIT:
                CPU_FOREACH_ISSET(i, &vme->u.ipi.dmask) {
                        error = vm_suspend_cpu(vcpu_info[i].vcpu);
                        if (error) {
                                warnx("%s: failed to suspend cpu %d\n",
                                    __func__, i);
                                break;
                        }
                }
                break;
        case APIC_DELMODE_STARTUP:
                CPU_FOREACH_ISSET(i, &vme->u.ipi.dmask) {
                        spinup_ap(vcpu_info[i].vcpu,
                            vme->u.ipi.vector << PAGE_SHIFT);
                }
                error = 0;
                break;
        default:
                break;
        }

        return (error);
}
#endif

const vmexit_handler_t vmexit_handlers[VM_EXITCODE_MAX] = {
        [VM_EXITCODE_INOUT]  = vmexit_inout,
#ifndef __FreeBSD__
        [VM_EXITCODE_MMIO]  = vmexit_mmio,
#endif
        [VM_EXITCODE_VMX]    = vmexit_vmx,
        [VM_EXITCODE_SVM]    = vmexit_svm,
        [VM_EXITCODE_BOGUS]  = vmexit_bogus,
        [VM_EXITCODE_RDMSR]  = vmexit_rdmsr,
        [VM_EXITCODE_WRMSR]  = vmexit_wrmsr,
        [VM_EXITCODE_MTRAP]  = vmexit_mtrap,
        [VM_EXITCODE_INST_EMUL] = vmexit_inst_emul,
#ifndef __FreeBSD__
        [VM_EXITCODE_RUN_STATE] = vmexit_run_state,
        [VM_EXITCODE_PAGING] = vmexit_paging,
#endif
        [VM_EXITCODE_SUSPENDED] = vmexit_suspend,
        [VM_EXITCODE_TASK_SWITCH] = vmexit_task_switch,
        [VM_EXITCODE_DEBUG] = vmexit_debug,
        [VM_EXITCODE_BPT] = vmexit_breakpoint,
#ifdef  __FreeBSD__
        [VM_EXITCODE_IPI] = vmexit_ipi,
#endif
        [VM_EXITCODE_HLT] = vmexit_hlt,
        [VM_EXITCODE_PAUSE] = vmexit_pause,
};