/*-
 * Copyright (c) 2009-2012,2016 Microsoft Corp.
 * Copyright (c) 2012 NetApp Inc.
 * Copyright (c) 2012 Citrix 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 unmodified, 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 THE AUTHOR ``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 THE AUTHOR 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.
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systimer.h>
#include <sys/systm.h>

#include <machine/cpufunc.h>

#include <dev/virtual/hyperv/hyperv_busdma.h>
#include <dev/virtual/hyperv/hyperv_machdep.h>
#include <dev/virtual/hyperv/hyperv_reg.h>
#include <dev/virtual/hyperv/hyperv_var.h>

#define HYPERV_DRAGONFLY_BUILD          0ULL
#define HYPERV_DRAGONFLY_VERSION        ((uint64_t)__DragonFly_version)
#define HYPERV_DRAGONFLY_OSID           0ULL

#define MSR_HV_GUESTID_BUILD_DRAGONFLY  \
        (HYPERV_DRAGONFLY_BUILD & MSR_HV_GUESTID_BUILD_MASK)
#define MSR_HV_GUESTID_VERSION_DRAGONFLY \
        ((HYPERV_DRAGONFLY_VERSION << MSR_HV_GUESTID_VERSION_SHIFT) & \
         MSR_HV_GUESTID_VERSION_MASK)
#define MSR_HV_GUESTID_OSID_DRAGONFLY   \
        ((HYPERV_DRAGONFLY_OSID << MSR_HV_GUESTID_OSID_SHIFT) & \
         MSR_HV_GUESTID_OSID_MASK)

#define MSR_HV_GUESTID_DRAGONFLY        \
        (MSR_HV_GUESTID_BUILD_DRAGONFLY | \
         MSR_HV_GUESTID_VERSION_DRAGONFLY | \
         MSR_HV_GUESTID_OSID_DRAGONFLY | \
         MSR_HV_GUESTID_OSTYPE_FREEBSD)

struct hypercall_ctx {
        void                    *hc_addr;
        struct hyperv_dma       hc_dma;
};

static void             hyperv_cputimer_construct(struct cputimer *,
                            sysclock_t);
static sysclock_t       hyperv_cputimer_count(void);
static boolean_t        hyperv_identify(void);
static int              hypercall_create(void);
static void             hypercall_destroy(void);
static void             hypercall_memfree(void);
static uint64_t         hyperv_tc64_rdmsr(void);

u_int                   hyperv_features;
static u_int            hyperv_recommends;

static u_int            hyperv_pm_features;
static u_int            hyperv_features3;

hyperv_tc64_t           hyperv_tc64;

static struct cputimer  hyperv_cputimer = {
        .next           = SLIST_ENTRY_INITIALIZER,
        .name           = "Hyper-V",
        .pri            = CPUTIMER_PRI_VMM,
        .type           = CPUTIMER_VMM,
        .count          = hyperv_cputimer_count,
        .fromhz         = cputimer_default_fromhz,
        .fromus         = cputimer_default_fromus,
        .construct      = hyperv_cputimer_construct,
        .destruct       = cputimer_default_destruct,
        .freq           = HYPERV_TIMER_FREQ
};

static struct cpucounter hyperv_cpucounter = {
        .freq           = HYPERV_TIMER_FREQ,
        .count          = hyperv_tc64_rdmsr,
        .flags          = CPUCOUNTER_FLAG_MPSYNC,
        .prio           = CPUCOUNTER_PRIO_VMM,
        .type           = CPUCOUNTER_VMM
};

static struct hypercall_ctx     hypercall_context;

uint64_t
hypercall_post_message(bus_addr_t msg_paddr)
{
        return hypercall_md(hypercall_context.hc_addr,
            HYPERCALL_POST_MESSAGE, msg_paddr, 0);
}

static void
hyperv_cputimer_construct(struct cputimer *timer, sysclock_t oldclock)
{
        timer->base = 0;
        timer->base = oldclock - timer->count();
}

static sysclock_t
hyperv_cputimer_count(void)
{
        uint64_t val;

        val = rdmsr(MSR_HV_TIME_REF_COUNT);
        return (val + hyperv_cputimer.base);
}

static void
hypercall_memfree(void)
{
        hyperv_dmamem_free(&hypercall_context.hc_dma,
            hypercall_context.hc_addr);
        hypercall_context.hc_addr = NULL;
}

static int
hypercall_create(void)
{
        uint64_t hc, hc_orig;

        hypercall_context.hc_addr = hyperv_dmamem_alloc(NULL, PAGE_SIZE, 0,
            PAGE_SIZE, &hypercall_context.hc_dma, BUS_DMA_WAITOK);
        if (hypercall_context.hc_addr == NULL) {
                kprintf("hyperv: Hypercall page allocation failed\n");
                return ENOMEM;
        }

        /* Get the 'reserved' bits, which requires preservation. */
        hc_orig = rdmsr(MSR_HV_HYPERCALL);

        /*
         * Setup the Hypercall page.
         *
         * NOTE: 'reserved' bits MUST be preserved.
         */
        hc = ((hypercall_context.hc_dma.hv_paddr >> PAGE_SHIFT) <<
            MSR_HV_HYPERCALL_PGSHIFT) |
            (hc_orig & MSR_HV_HYPERCALL_RSVD_MASK) |
            MSR_HV_HYPERCALL_ENABLE;
        wrmsr(MSR_HV_HYPERCALL, hc);

        /*
         * Confirm that Hypercall page did get setup.
         */
        hc = rdmsr(MSR_HV_HYPERCALL);
        if ((hc & MSR_HV_HYPERCALL_ENABLE) == 0) {
                kprintf("hyperv: Hypercall setup failed\n");
                hypercall_memfree();
                return EIO;
        }
        if (bootverbose)
                kprintf("hyperv: Hypercall created\n");

        return 0;
}

static void
hypercall_destroy(void)
{
        uint64_t hc;

        if (hypercall_context.hc_addr == NULL)
                return;

        /* Disable Hypercall */
        hc = rdmsr(MSR_HV_HYPERCALL);
        wrmsr(MSR_HV_HYPERCALL, (hc & MSR_HV_HYPERCALL_RSVD_MASK));
        hypercall_memfree();

        if (bootverbose)
                kprintf("hyperv: Hypercall destroyed\n");
}

static uint64_t
hyperv_tc64_rdmsr(void)
{

        return (rdmsr(MSR_HV_TIME_REF_COUNT));
}

static boolean_t
hyperv_identify(void)
{
        u_int regs[4];
        unsigned int maxleaf;

        if (vmm_guest != VMM_GUEST_HYPERV)
                return (FALSE);

        do_cpuid(CPUID_LEAF_HV_MAXLEAF, regs);
        maxleaf = regs[0];
        if (maxleaf < CPUID_LEAF_HV_LIMITS)
                return (FALSE);

        do_cpuid(CPUID_LEAF_HV_INTERFACE, regs);
        if (regs[0] != CPUID_HV_IFACE_HYPERV)
                return (FALSE);

        do_cpuid(CPUID_LEAF_HV_FEATURES, regs);
        if ((regs[0] & CPUID_HV_MSR_HYPERCALL) == 0) {
                /*
                 * Hyper-V w/o Hypercall is impossible; someone
                 * is faking Hyper-V.
                 */
                return (FALSE);
        }
        hyperv_features = regs[0];
        hyperv_pm_features = regs[2];
        hyperv_features3 = regs[3];

        do_cpuid(CPUID_LEAF_HV_IDENTITY, regs);
        kprintf("Hyper-V Version: %d.%d.%d [SP%d]\n",
            regs[1] >> 16, regs[1] & 0xffff, regs[0], regs[2]);

        kprintf("  Features=0x%pb%i\n",
            "\020"
            "\001VPRUNTIME"     /* MSR_HV_VP_RUNTIME */
            "\002TMREFCNT"      /* MSR_HV_TIME_REF_COUNT */
            "\003SYNIC"         /* MSRs for SynIC */
            "\004SYNTM"         /* MSRs for SynTimer */
            "\005APIC"          /* MSR_HV_{EOI,ICR,TPR} */
            "\006HYPERCALL"     /* MSR_HV_{GUEST_OS_ID,HYPERCALL} */
            "\007VPINDEX"       /* MSR_HV_VP_INDEX */
            "\010RESET"         /* MSR_HV_RESET */
            "\011STATS"         /* MSR_HV_STATS_ */
            "\012REFTSC"        /* MSR_HV_REFERENCE_TSC */
            "\013IDLE"          /* MSR_HV_GUEST_IDLE */
            "\014TMFREQ"        /* MSR_HV_{TSC,APIC}_FREQUENCY */
            "\015DEBUG",        /* MSR_HV_SYNTH_DEBUG_ */
            hyperv_features);
        kprintf("  PM Features=0x%pb%i [C%u]\n",
            "\020"
            "\005C3HPET",       /* HPET is required for C3 state */
            (hyperv_pm_features & ~CPUPM_HV_CSTATE_MASK),
            CPUPM_HV_CSTATE(hyperv_pm_features));
        kprintf("  Features3=0x%pb%i\n",
            "\020"
            "\001MWAIT"         /* MWAIT */
            "\002DEBUG"         /* guest debug support */
            "\003PERFMON"       /* performance monitor */
            "\004PCPUDPE"       /* physical CPU dynamic partition event */
            "\005XMMHC"         /* hypercall input through XMM regs */
            "\006IDLE"          /* guest idle support */
            "\007SLEEP"         /* hypervisor sleep support */
            "\010NUMA"          /* NUMA distance query support */
            "\011TMFREQ"        /* timer frequency query (TSC, LAPIC) */
            "\012SYNCMC"        /* inject synthetic machine checks */
            "\013CRASH"         /* MSRs for guest crash */
            "\014DEBUGMSR"      /* MSRs for guest debug */
            "\015NPIEP"         /* NPIEP */
            "\016HVDIS",        /* disabling hypervisor */
            hyperv_features3);

        do_cpuid(CPUID_LEAF_HV_RECOMMENDS, regs);
        hyperv_recommends = regs[0];
        if (bootverbose)
                kprintf("  Recommends: %08x %08x\n", regs[0], regs[1]);

        do_cpuid(CPUID_LEAF_HV_LIMITS, regs);
        if (bootverbose) {
                kprintf("  Limits: Vcpu:%d Lcpu:%d Int:%d\n",
                    regs[0], regs[1], regs[2]);
        }

        if (maxleaf >= CPUID_LEAF_HV_HWFEATURES) {
                do_cpuid(CPUID_LEAF_HV_HWFEATURES, regs);
                if (bootverbose) {
                        kprintf("  HW Features: %08x, AMD: %08x\n",
                            regs[0], regs[3]);
                }
        }

        return (TRUE);
}

static void
hyperv_init(void *dummy __unused)
{
        int error;

        if (!hyperv_identify()) {
                /* Not Hyper-V; reset guest id to the generic one. */
                if (vmm_guest == VMM_GUEST_HYPERV)
                        vmm_guest = VMM_GUEST_UNKNOWN;
                return;
        }

        /* Set guest id */
        wrmsr(MSR_HV_GUEST_OS_ID, MSR_HV_GUESTID_DRAGONFLY);

        if (hyperv_features & CPUID_HV_MSR_TIME_REFCNT) {
                /* Register Hyper-V cputimers */
                cputimer_register(&hyperv_cputimer);
                cputimer_select(&hyperv_cputimer, 0);
                cpucounter_register(&hyperv_cpucounter);
                hyperv_tc64 = hyperv_tc64_rdmsr;
        }

        error = hypercall_create();
        if (error) {
                /* Can't perform any Hyper-V specific actions */
                vmm_guest = VMM_GUEST_UNKNOWN;
        }

        /* Machine dependent initialization. */
        hyperv_md_init();
}
SYSINIT(hyperv_initialize, SI_SUB_PRE_DRIVERS, SI_ORDER_FIRST,
    hyperv_init, NULL);

static void
hyperv_uninit(void *dummy __unused)
{
        /* Machine dependent uninitialization. */
        hyperv_md_uninit();

        if (hyperv_features & CPUID_HV_MSR_TIME_REFCNT) {
                /* Deregister Hyper-V systimer */
                cputimer_deregister(&hyperv_cputimer);
        }
        hypercall_destroy();
}
SYSUNINIT(hyperv_uninitialize, SI_SUB_PRE_DRIVERS, SI_ORDER_FIRST,
    hyperv_uninit, NULL);