// SPDX-License-Identifier: GPL-2.0-only
/*
 * Kernel-based Virtual Machine driver for Linux
 *
 * derived from drivers/kvm/kvm_main.c
 *
 * Copyright (C) 2006 Qumranet, Inc.
 * Copyright (C) 2008 Qumranet, Inc.
 * Copyright IBM Corporation, 2008
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 *
 * Authors:
 *   Avi Kivity   <avi@qumranet.com>
 *   Yaniv Kamay  <yaniv@qumranet.com>
 *   Amit Shah    <amit.shah@qumranet.com>
 *   Ben-Ami Yassour <benami@il.ibm.com>
 */

#include <linux/kvm_host.h>
#include "irq.h"
#include "ioapic.h"
#include "mmu.h"
#include "i8254.h"
#include "tss.h"
#include "kvm_cache_regs.h"
#include "kvm_emulate.h"
#include "x86.h"
#include "cpuid.h"
#include "pmu.h"
#include "hyperv.h"
#include "lapic.h"

#include <linux/clocksource.h>
#include <linux/interrupt.h>
#include <linux/kvm.h>
#include <linux/fs.h>
#include <linux/vmalloc.h>
#include <linux/export.h>
#include <linux/moduleparam.h>
#include <linux/mman.h>
#include <linux/highmem.h>
#include <linux/iommu.h>
#include <linux/intel-iommu.h>
#include <linux/cpufreq.h>
#include <linux/user-return-notifier.h>
#include <linux/srcu.h>
#include <linux/slab.h>
#include <linux/perf_event.h>
#include <linux/uaccess.h>
#include <linux/hash.h>
#include <linux/pci.h>
#include <linux/timekeeper_internal.h>
#include <linux/pvclock_gtod.h>
#include <linux/kvm_irqfd.h>
#include <linux/irqbypass.h>
#include <linux/sched/stat.h>
#include <linux/sched/isolation.h>
#include <linux/mem_encrypt.h>
#include <linux/entry-kvm.h>

#include <trace/events/kvm.h>

#include <asm/debugreg.h>
#include <asm/msr.h>
#include <asm/desc.h>
#include <asm/mce.h>
#include <linux/kernel_stat.h>
#include <asm/fpu/internal.h> /* Ugh! */
#include <asm/pvclock.h>
#include <asm/div64.h>
#include <asm/irq_remapping.h>
#include <asm/mshyperv.h>
#include <asm/hypervisor.h>
#include <asm/intel_pt.h>
#include <asm/emulate_prefix.h>
#include <clocksource/hyperv_timer.h>

#define CREATE_TRACE_POINTS
#include "trace.h"

#define MAX_IO_MSRS 256
#define KVM_MAX_MCE_BANKS 32
u64 __read_mostly kvm_mce_cap_supported = MCG_CTL_P | MCG_SER_P;
EXPORT_SYMBOL_GPL(kvm_mce_cap_supported);

#define emul_to_vcpu(ctxt) \
        ((struct kvm_vcpu *)(ctxt)->vcpu)

/* EFER defaults:
 * - enable syscall per default because its emulated by KVM
 * - enable LME and LMA per default on 64 bit KVM
 */
#ifdef CONFIG_X86_64
static
u64 __read_mostly efer_reserved_bits = ~((u64)(EFER_SCE | EFER_LME | EFER_LMA));
#else
static u64 __read_mostly efer_reserved_bits = ~((u64)EFER_SCE);
#endif

static u64 __read_mostly cr4_reserved_bits = CR4_RESERVED_BITS;

#define KVM_X2APIC_API_VALID_FLAGS (KVM_X2APIC_API_USE_32BIT_IDS | \
                                    KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK)

static void update_cr8_intercept(struct kvm_vcpu *vcpu);
static void process_nmi(struct kvm_vcpu *vcpu);
static void enter_smm(struct kvm_vcpu *vcpu);
static void __kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags);
static void store_regs(struct kvm_vcpu *vcpu);
static int sync_regs(struct kvm_vcpu *vcpu);

struct kvm_x86_ops kvm_x86_ops __read_mostly;
EXPORT_SYMBOL_GPL(kvm_x86_ops);

static bool __read_mostly ignore_msrs = 0;
module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);

static bool __read_mostly report_ignored_msrs = true;
module_param(report_ignored_msrs, bool, S_IRUGO | S_IWUSR);

unsigned int min_timer_period_us = 200;
module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR);

static bool __read_mostly kvmclock_periodic_sync = true;
module_param(kvmclock_periodic_sync, bool, S_IRUGO);

bool __read_mostly kvm_has_tsc_control;
EXPORT_SYMBOL_GPL(kvm_has_tsc_control);
u32  __read_mostly kvm_max_guest_tsc_khz;
EXPORT_SYMBOL_GPL(kvm_max_guest_tsc_khz);
u8   __read_mostly kvm_tsc_scaling_ratio_frac_bits;
EXPORT_SYMBOL_GPL(kvm_tsc_scaling_ratio_frac_bits);
u64  __read_mostly kvm_max_tsc_scaling_ratio;
EXPORT_SYMBOL_GPL(kvm_max_tsc_scaling_ratio);
u64 __read_mostly kvm_default_tsc_scaling_ratio;
EXPORT_SYMBOL_GPL(kvm_default_tsc_scaling_ratio);

/* tsc tolerance in parts per million - default to 1/2 of the NTP threshold */
static u32 __read_mostly tsc_tolerance_ppm = 250;
module_param(tsc_tolerance_ppm, uint, S_IRUGO | S_IWUSR);

/*
 * lapic timer advance (tscdeadline mode only) in nanoseconds.  '-1' enables
 * adaptive tuning starting from default advancment of 1000ns.  '0' disables
 * advancement entirely.  Any other value is used as-is and disables adaptive
 * tuning, i.e. allows priveleged userspace to set an exact advancement time.
 */
static int __read_mostly lapic_timer_advance_ns = -1;
module_param(lapic_timer_advance_ns, int, S_IRUGO | S_IWUSR);

static bool __read_mostly vector_hashing = true;
module_param(vector_hashing, bool, S_IRUGO);

bool __read_mostly enable_vmware_backdoor = false;
module_param(enable_vmware_backdoor, bool, S_IRUGO);
EXPORT_SYMBOL_GPL(enable_vmware_backdoor);

static bool __read_mostly force_emulation_prefix = false;
module_param(force_emulation_prefix, bool, S_IRUGO);

int __read_mostly pi_inject_timer = -1;
module_param(pi_inject_timer, bint, S_IRUGO | S_IWUSR);

#define KVM_NR_SHARED_MSRS 16

struct kvm_shared_msrs_global {
        int nr;
        u32 msrs[KVM_NR_SHARED_MSRS];
};

struct kvm_shared_msrs {
        struct user_return_notifier urn;
        bool registered;
        struct kvm_shared_msr_values {
                u64 host;
                u64 curr;
        } values[KVM_NR_SHARED_MSRS];
};

static struct kvm_shared_msrs_global __read_mostly shared_msrs_global;
static struct kvm_shared_msrs __percpu *shared_msrs;

#define KVM_SUPPORTED_XCR0     (XFEATURE_MASK_FP | XFEATURE_MASK_SSE \
                                | XFEATURE_MASK_YMM | XFEATURE_MASK_BNDREGS \
                                | XFEATURE_MASK_BNDCSR | XFEATURE_MASK_AVX512 \
                                | XFEATURE_MASK_PKRU)

u64 __read_mostly host_efer;
EXPORT_SYMBOL_GPL(host_efer);

bool __read_mostly allow_smaller_maxphyaddr = 0;
EXPORT_SYMBOL_GPL(allow_smaller_maxphyaddr);

static u64 __read_mostly host_xss;
u64 __read_mostly supported_xss;
EXPORT_SYMBOL_GPL(supported_xss);

struct kvm_stats_debugfs_item debugfs_entries[] = {
        VCPU_STAT("pf_fixed", pf_fixed),
        VCPU_STAT("pf_guest", pf_guest),
        VCPU_STAT("tlb_flush", tlb_flush),
        VCPU_STAT("invlpg", invlpg),
        VCPU_STAT("exits", exits),
        VCPU_STAT("io_exits", io_exits),
        VCPU_STAT("mmio_exits", mmio_exits),
        VCPU_STAT("signal_exits", signal_exits),
        VCPU_STAT("irq_window", irq_window_exits),
        VCPU_STAT("nmi_window", nmi_window_exits),
        VCPU_STAT("halt_exits", halt_exits),
        VCPU_STAT("halt_successful_poll", halt_successful_poll),
        VCPU_STAT("halt_attempted_poll", halt_attempted_poll),
        VCPU_STAT("halt_poll_invalid", halt_poll_invalid),
        VCPU_STAT("halt_wakeup", halt_wakeup),
        VCPU_STAT("hypercalls", hypercalls),
        VCPU_STAT("request_irq", request_irq_exits),
        VCPU_STAT("irq_exits", irq_exits),
        VCPU_STAT("host_state_reload", host_state_reload),
        VCPU_STAT("fpu_reload", fpu_reload),
        VCPU_STAT("insn_emulation", insn_emulation),
        VCPU_STAT("insn_emulation_fail", insn_emulation_fail),
        VCPU_STAT("irq_injections", irq_injections),
        VCPU_STAT("nmi_injections", nmi_injections),
        VCPU_STAT("req_event", req_event),
        VCPU_STAT("l1d_flush", l1d_flush),
        VCPU_STAT("halt_poll_success_ns", halt_poll_success_ns),
        VCPU_STAT("halt_poll_fail_ns", halt_poll_fail_ns),
        VM_STAT("mmu_shadow_zapped", mmu_shadow_zapped),
        VM_STAT("mmu_pte_write", mmu_pte_write),
        VM_STAT("mmu_pte_updated", mmu_pte_updated),
        VM_STAT("mmu_pde_zapped", mmu_pde_zapped),
        VM_STAT("mmu_flooded", mmu_flooded),
        VM_STAT("mmu_recycled", mmu_recycled),
        VM_STAT("mmu_cache_miss", mmu_cache_miss),
        VM_STAT("mmu_unsync", mmu_unsync),
        VM_STAT("remote_tlb_flush", remote_tlb_flush),
        VM_STAT("largepages", lpages, .mode = 0444),
        VM_STAT("nx_largepages_splitted", nx_lpage_splits, .mode = 0444),
        VM_STAT("max_mmu_page_hash_collisions", max_mmu_page_hash_collisions),
        { NULL }
};

u64 __read_mostly host_xcr0;
u64 __read_mostly supported_xcr0;
EXPORT_SYMBOL_GPL(supported_xcr0);

static struct kmem_cache *x86_fpu_cache;

static struct kmem_cache *x86_emulator_cache;

/*
 * When called, it means the previous get/set msr reached an invalid msr.
 * Return 0 if we want to ignore/silent this failed msr access, or 1 if we want
 * to fail the caller.
 */
static int kvm_msr_ignored_check(struct kvm_vcpu *vcpu, u32 msr,
                                 u64 data, bool write)
{
        const char *op = write ? "wrmsr" : "rdmsr";

        if (ignore_msrs) {
                if (report_ignored_msrs)
                        vcpu_unimpl(vcpu, "ignored %s: 0x%x data 0x%llx\n",
                                    op, msr, data);
                /* Mask the error */
                return 0;
        } else {
                vcpu_debug_ratelimited(vcpu, "unhandled %s: 0x%x data 0x%llx\n",
                                       op, msr, data);
                return 1;
        }
}

static struct kmem_cache *kvm_alloc_emulator_cache(void)
{
        unsigned int useroffset = offsetof(struct x86_emulate_ctxt, src);
        unsigned int size = sizeof(struct x86_emulate_ctxt);

        return kmem_cache_create_usercopy("x86_emulator", size,
                                          __alignof__(struct x86_emulate_ctxt),
                                          SLAB_ACCOUNT, useroffset,
                                          size - useroffset, NULL);
}

static int emulator_fix_hypercall(struct x86_emulate_ctxt *ctxt);

static inline void kvm_async_pf_hash_reset(struct kvm_vcpu *vcpu)
{
        int i;
        for (i = 0; i < ASYNC_PF_PER_VCPU; i++)
                vcpu->arch.apf.gfns[i] = ~0;
}

static void kvm_on_user_return(struct user_return_notifier *urn)
{
        unsigned slot;
        struct kvm_shared_msrs *locals
                = container_of(urn, struct kvm_shared_msrs, urn);
        struct kvm_shared_msr_values *values;
        unsigned long flags;

        /*
         * Disabling irqs at this point since the following code could be
         * interrupted and executed through kvm_arch_hardware_disable()
         */
        local_irq_save(flags);
        if (locals->registered) {
                locals->registered = false;
                user_return_notifier_unregister(urn);
        }
        local_irq_restore(flags);
        for (slot = 0; slot < shared_msrs_global.nr; ++slot) {
                values = &locals->values[slot];
                if (values->host != values->curr) {
                        wrmsrl(shared_msrs_global.msrs[slot], values->host);
                        values->curr = values->host;
                }
        }
}

void kvm_define_shared_msr(unsigned slot, u32 msr)
{
        BUG_ON(slot >= KVM_NR_SHARED_MSRS);
        shared_msrs_global.msrs[slot] = msr;
        if (slot >= shared_msrs_global.nr)
                shared_msrs_global.nr = slot + 1;
}
EXPORT_SYMBOL_GPL(kvm_define_shared_msr);

static void kvm_shared_msr_cpu_online(void)
{
        unsigned int cpu = smp_processor_id();
        struct kvm_shared_msrs *smsr = per_cpu_ptr(shared_msrs, cpu);
        u64 value;
        int i;

        for (i = 0; i < shared_msrs_global.nr; ++i) {
                rdmsrl_safe(shared_msrs_global.msrs[i], &value);
                smsr->values[i].host = value;
                smsr->values[i].curr = value;
        }
}

int kvm_set_shared_msr(unsigned slot, u64 value, u64 mask)
{
        unsigned int cpu = smp_processor_id();
        struct kvm_shared_msrs *smsr = per_cpu_ptr(shared_msrs, cpu);
        int err;

        value = (value & mask) | (smsr->values[slot].host & ~mask);
        if (value == smsr->values[slot].curr)
                return 0;
        err = wrmsrl_safe(shared_msrs_global.msrs[slot], value);
        if (err)
                return 1;

        smsr->values[slot].curr = value;
        if (!smsr->registered) {
                smsr->urn.on_user_return = kvm_on_user_return;
                user_return_notifier_register(&smsr->urn);
                smsr->registered = true;
        }
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_shared_msr);

static void drop_user_return_notifiers(void)
{
        unsigned int cpu = smp_processor_id();
        struct kvm_shared_msrs *smsr = per_cpu_ptr(shared_msrs, cpu);

        if (smsr->registered)
                kvm_on_user_return(&smsr->urn);
}

u64 kvm_get_apic_base(struct kvm_vcpu *vcpu)
{
        return vcpu->arch.apic_base;
}
EXPORT_SYMBOL_GPL(kvm_get_apic_base);

enum lapic_mode kvm_get_apic_mode(struct kvm_vcpu *vcpu)
{
        return kvm_apic_mode(kvm_get_apic_base(vcpu));
}
EXPORT_SYMBOL_GPL(kvm_get_apic_mode);

int kvm_set_apic_base(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
        enum lapic_mode old_mode = kvm_get_apic_mode(vcpu);
        enum lapic_mode new_mode = kvm_apic_mode(msr_info->data);
        u64 reserved_bits = ((~0ULL) << cpuid_maxphyaddr(vcpu)) | 0x2ff |
                (guest_cpuid_has(vcpu, X86_FEATURE_X2APIC) ? 0 : X2APIC_ENABLE);

        if ((msr_info->data & reserved_bits) != 0 || new_mode == LAPIC_MODE_INVALID)
                return 1;
        if (!msr_info->host_initiated) {
                if (old_mode == LAPIC_MODE_X2APIC && new_mode == LAPIC_MODE_XAPIC)
                        return 1;
                if (old_mode == LAPIC_MODE_DISABLED && new_mode == LAPIC_MODE_X2APIC)
                        return 1;
        }

        kvm_lapic_set_base(vcpu, msr_info->data);
        kvm_recalculate_apic_map(vcpu->kvm);
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_apic_base);

asmlinkage __visible noinstr void kvm_spurious_fault(void)
{
        /* Fault while not rebooting.  We want the trace. */
        BUG_ON(!kvm_rebooting);
}
EXPORT_SYMBOL_GPL(kvm_spurious_fault);

#define EXCPT_BENIGN            0
#define EXCPT_CONTRIBUTORY      1
#define EXCPT_PF                2

static int exception_class(int vector)
{
        switch (vector) {
        case PF_VECTOR:
                return EXCPT_PF;
        case DE_VECTOR:
        case TS_VECTOR:
        case NP_VECTOR:
        case SS_VECTOR:
        case GP_VECTOR:
                return EXCPT_CONTRIBUTORY;
        default:
                break;
        }
        return EXCPT_BENIGN;
}

#define EXCPT_FAULT             0
#define EXCPT_TRAP              1
#define EXCPT_ABORT             2
#define EXCPT_INTERRUPT         3

static int exception_type(int vector)
{
        unsigned int mask;

        if (WARN_ON(vector > 31 || vector == NMI_VECTOR))
                return EXCPT_INTERRUPT;

        mask = 1 << vector;

        /* #DB is trap, as instruction watchpoints are handled elsewhere */
        if (mask & ((1 << DB_VECTOR) | (1 << BP_VECTOR) | (1 << OF_VECTOR)))
                return EXCPT_TRAP;

        if (mask & ((1 << DF_VECTOR) | (1 << MC_VECTOR)))
                return EXCPT_ABORT;

        /* Reserved exceptions will result in fault */
        return EXCPT_FAULT;
}

void kvm_deliver_exception_payload(struct kvm_vcpu *vcpu)
{
        unsigned nr = vcpu->arch.exception.nr;
        bool has_payload = vcpu->arch.exception.has_payload;
        unsigned long payload = vcpu->arch.exception.payload;

        if (!has_payload)
                return;

        switch (nr) {
        case DB_VECTOR:
                /*
                 * "Certain debug exceptions may clear bit 0-3.  The
                 * remaining contents of the DR6 register are never
                 * cleared by the processor".
                 */
                vcpu->arch.dr6 &= ~DR_TRAP_BITS;
                /*
                 * DR6.RTM is set by all #DB exceptions that don't clear it.
                 */
                vcpu->arch.dr6 |= DR6_RTM;
                vcpu->arch.dr6 |= payload;
                /*
                 * Bit 16 should be set in the payload whenever the #DB
                 * exception should clear DR6.RTM. This makes the payload
                 * compatible with the pending debug exceptions under VMX.
                 * Though not currently documented in the SDM, this also
                 * makes the payload compatible with the exit qualification
                 * for #DB exceptions under VMX.
                 */
                vcpu->arch.dr6 ^= payload & DR6_RTM;

                /*
                 * The #DB payload is defined as compatible with the 'pending
                 * debug exceptions' field under VMX, not DR6. While bit 12 is
                 * defined in the 'pending debug exceptions' field (enabled
                 * breakpoint), it is reserved and must be zero in DR6.
                 */
                vcpu->arch.dr6 &= ~BIT(12);
                break;
        case PF_VECTOR:
                vcpu->arch.cr2 = payload;
                break;
        }

        vcpu->arch.exception.has_payload = false;
        vcpu->arch.exception.payload = 0;
}
EXPORT_SYMBOL_GPL(kvm_deliver_exception_payload);

static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
                unsigned nr, bool has_error, u32 error_code,
                bool has_payload, unsigned long payload, bool reinject)
{
        u32 prev_nr;
        int class1, class2;

        kvm_make_request(KVM_REQ_EVENT, vcpu);

        if (!vcpu->arch.exception.pending && !vcpu->arch.exception.injected) {
        queue:
                if (has_error && !is_protmode(vcpu))
                        has_error = false;
                if (reinject) {
                        /*
                         * On vmentry, vcpu->arch.exception.pending is only
                         * true if an event injection was blocked by
                         * nested_run_pending.  In that case, however,
                         * vcpu_enter_guest requests an immediate exit,
                         * and the guest shouldn't proceed far enough to
                         * need reinjection.
                         */
                        WARN_ON_ONCE(vcpu->arch.exception.pending);
                        vcpu->arch.exception.injected = true;
                        if (WARN_ON_ONCE(has_payload)) {
                                /*
                                 * A reinjected event has already
                                 * delivered its payload.
                                 */
                                has_payload = false;
                                payload = 0;
                        }
                } else {
                        vcpu->arch.exception.pending = true;
                        vcpu->arch.exception.injected = false;
                }
                vcpu->arch.exception.has_error_code = has_error;
                vcpu->arch.exception.nr = nr;
                vcpu->arch.exception.error_code = error_code;
                vcpu->arch.exception.has_payload = has_payload;
                vcpu->arch.exception.payload = payload;
                if (!is_guest_mode(vcpu))
                        kvm_deliver_exception_payload(vcpu);
                return;
        }

        /* to check exception */
        prev_nr = vcpu->arch.exception.nr;
        if (prev_nr == DF_VECTOR) {
                /* triple fault -> shutdown */
                kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
                return;
        }
        class1 = exception_class(prev_nr);
        class2 = exception_class(nr);
        if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY)
                || (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
                /*
                 * Generate double fault per SDM Table 5-5.  Set
                 * exception.pending = true so that the double fault
                 * can trigger a nested vmexit.
                 */
                vcpu->arch.exception.pending = true;
                vcpu->arch.exception.injected = false;
                vcpu->arch.exception.has_error_code = true;
                vcpu->arch.exception.nr = DF_VECTOR;
                vcpu->arch.exception.error_code = 0;
                vcpu->arch.exception.has_payload = false;
                vcpu->arch.exception.payload = 0;
        } else
                /* replace previous exception with a new one in a hope
                   that instruction re-execution will regenerate lost
                   exception */
                goto queue;
}

void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr)
{
        kvm_multiple_exception(vcpu, nr, false, 0, false, 0, false);
}
EXPORT_SYMBOL_GPL(kvm_queue_exception);

void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr)
{
        kvm_multiple_exception(vcpu, nr, false, 0, false, 0, true);
}
EXPORT_SYMBOL_GPL(kvm_requeue_exception);

void kvm_queue_exception_p(struct kvm_vcpu *vcpu, unsigned nr,
                           unsigned long payload)
{
        kvm_multiple_exception(vcpu, nr, false, 0, true, payload, false);
}
EXPORT_SYMBOL_GPL(kvm_queue_exception_p);

static void kvm_queue_exception_e_p(struct kvm_vcpu *vcpu, unsigned nr,
                                    u32 error_code, unsigned long payload)
{
        kvm_multiple_exception(vcpu, nr, true, error_code,
                               true, payload, false);
}

int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err)
{
        if (err)
                kvm_inject_gp(vcpu, 0);
        else
                return kvm_skip_emulated_instruction(vcpu);

        return 1;
}
EXPORT_SYMBOL_GPL(kvm_complete_insn_gp);

void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault)
{
        ++vcpu->stat.pf_guest;
        vcpu->arch.exception.nested_apf =
                is_guest_mode(vcpu) && fault->async_page_fault;
        if (vcpu->arch.exception.nested_apf) {
                vcpu->arch.apf.nested_apf_token = fault->address;
                kvm_queue_exception_e(vcpu, PF_VECTOR, fault->error_code);
        } else {
                kvm_queue_exception_e_p(vcpu, PF_VECTOR, fault->error_code,
                                        fault->address);
        }
}
EXPORT_SYMBOL_GPL(kvm_inject_page_fault);

bool kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu,
                                    struct x86_exception *fault)
{
        struct kvm_mmu *fault_mmu;
        WARN_ON_ONCE(fault->vector != PF_VECTOR);

        fault_mmu = fault->nested_page_fault ? vcpu->arch.mmu :
                                               vcpu->arch.walk_mmu;

        /*
         * Invalidate the TLB entry for the faulting address, if it exists,
         * else the access will fault indefinitely (and to emulate hardware).
         */
        if ((fault->error_code & PFERR_PRESENT_MASK) &&
            !(fault->error_code & PFERR_RSVD_MASK))
                kvm_mmu_invalidate_gva(vcpu, fault_mmu, fault->address,
                                       fault_mmu->root_hpa);

        fault_mmu->inject_page_fault(vcpu, fault);
        return fault->nested_page_fault;
}
EXPORT_SYMBOL_GPL(kvm_inject_emulated_page_fault);

void kvm_inject_nmi(struct kvm_vcpu *vcpu)
{
        atomic_inc(&vcpu->arch.nmi_queued);
        kvm_make_request(KVM_REQ_NMI, vcpu);
}
EXPORT_SYMBOL_GPL(kvm_inject_nmi);

void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code)
{
        kvm_multiple_exception(vcpu, nr, true, error_code, false, 0, false);
}
EXPORT_SYMBOL_GPL(kvm_queue_exception_e);

void kvm_requeue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code)
{
        kvm_multiple_exception(vcpu, nr, true, error_code, false, 0, true);
}
EXPORT_SYMBOL_GPL(kvm_requeue_exception_e);

/*
 * Checks if cpl <= required_cpl; if true, return true.  Otherwise queue
 * a #GP and return false.
 */
bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl)
{
        if (kvm_x86_ops.get_cpl(vcpu) <= required_cpl)
                return true;
        kvm_queue_exception_e(vcpu, GP_VECTOR, 0);
        return false;
}
EXPORT_SYMBOL_GPL(kvm_require_cpl);

bool kvm_require_dr(struct kvm_vcpu *vcpu, int dr)
{
        if ((dr != 4 && dr != 5) || !kvm_read_cr4_bits(vcpu, X86_CR4_DE))
                return true;

        kvm_queue_exception(vcpu, UD_VECTOR);
        return false;
}
EXPORT_SYMBOL_GPL(kvm_require_dr);

/*
 * This function will be used to read from the physical memory of the currently
 * running guest. The difference to kvm_vcpu_read_guest_page is that this function
 * can read from guest physical or from the guest's guest physical memory.
 */
int kvm_read_guest_page_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
                            gfn_t ngfn, void *data, int offset, int len,
                            u32 access)
{
        struct x86_exception exception;
        gfn_t real_gfn;
        gpa_t ngpa;

        ngpa     = gfn_to_gpa(ngfn);
        real_gfn = mmu->translate_gpa(vcpu, ngpa, access, &exception);
        if (real_gfn == UNMAPPED_GVA)
                return -EFAULT;

        real_gfn = gpa_to_gfn(real_gfn);

        return kvm_vcpu_read_guest_page(vcpu, real_gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_read_guest_page_mmu);

static int kvm_read_nested_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
                               void *data, int offset, int len, u32 access)
{
        return kvm_read_guest_page_mmu(vcpu, vcpu->arch.walk_mmu, gfn,
                                       data, offset, len, access);
}

static inline u64 pdptr_rsvd_bits(struct kvm_vcpu *vcpu)
{
        return rsvd_bits(cpuid_maxphyaddr(vcpu), 63) | rsvd_bits(5, 8) |
               rsvd_bits(1, 2);
}

/*
 * Load the pae pdptrs.  Return 1 if they are all valid, 0 otherwise.
 */
int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3)
{
        gfn_t pdpt_gfn = cr3 >> PAGE_SHIFT;
        unsigned offset = ((cr3 & (PAGE_SIZE-1)) >> 5) << 2;
        int i;
        int ret;
        u64 pdpte[ARRAY_SIZE(mmu->pdptrs)];

        ret = kvm_read_guest_page_mmu(vcpu, mmu, pdpt_gfn, pdpte,
                                      offset * sizeof(u64), sizeof(pdpte),
                                      PFERR_USER_MASK|PFERR_WRITE_MASK);
        if (ret < 0) {
                ret = 0;
                goto out;
        }
        for (i = 0; i < ARRAY_SIZE(pdpte); ++i) {
                if ((pdpte[i] & PT_PRESENT_MASK) &&
                    (pdpte[i] & pdptr_rsvd_bits(vcpu))) {
                        ret = 0;
                        goto out;
                }
        }
        ret = 1;

        memcpy(mmu->pdptrs, pdpte, sizeof(mmu->pdptrs));
        kvm_register_mark_dirty(vcpu, VCPU_EXREG_PDPTR);

out:

        return ret;
}
EXPORT_SYMBOL_GPL(load_pdptrs);

bool pdptrs_changed(struct kvm_vcpu *vcpu)
{
        u64 pdpte[ARRAY_SIZE(vcpu->arch.walk_mmu->pdptrs)];
        int offset;
        gfn_t gfn;
        int r;

        if (!is_pae_paging(vcpu))
                return false;

        if (!kvm_register_is_available(vcpu, VCPU_EXREG_PDPTR))
                return true;

        gfn = (kvm_read_cr3(vcpu) & 0xffffffe0ul) >> PAGE_SHIFT;
        offset = (kvm_read_cr3(vcpu) & 0xffffffe0ul) & (PAGE_SIZE - 1);
        r = kvm_read_nested_guest_page(vcpu, gfn, pdpte, offset, sizeof(pdpte),
                                       PFERR_USER_MASK | PFERR_WRITE_MASK);
        if (r < 0)
                return true;

        return memcmp(pdpte, vcpu->arch.walk_mmu->pdptrs, sizeof(pdpte)) != 0;
}
EXPORT_SYMBOL_GPL(pdptrs_changed);

int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{
        unsigned long old_cr0 = kvm_read_cr0(vcpu);
        unsigned long pdptr_bits = X86_CR0_CD | X86_CR0_NW | X86_CR0_PG;
        unsigned long update_bits = X86_CR0_PG | X86_CR0_WP;

        cr0 |= X86_CR0_ET;

#ifdef CONFIG_X86_64
        if (cr0 & 0xffffffff00000000UL)
                return 1;
#endif

        cr0 &= ~CR0_RESERVED_BITS;

        if ((cr0 & X86_CR0_NW) && !(cr0 & X86_CR0_CD))
                return 1;

        if ((cr0 & X86_CR0_PG) && !(cr0 & X86_CR0_PE))
                return 1;

#ifdef CONFIG_X86_64
        if ((vcpu->arch.efer & EFER_LME) && !is_paging(vcpu) &&
            (cr0 & X86_CR0_PG)) {
                int cs_db, cs_l;

                if (!is_pae(vcpu))
                        return 1;
                kvm_x86_ops.get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
                if (cs_l)
                        return 1;
        }
#endif
        if (!(vcpu->arch.efer & EFER_LME) && (cr0 & X86_CR0_PG) &&
            is_pae(vcpu) && ((cr0 ^ old_cr0) & pdptr_bits) &&
            !load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu)))
                return 1;

        if (!(cr0 & X86_CR0_PG) && kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE))
                return 1;

        kvm_x86_ops.set_cr0(vcpu, cr0);

        if ((cr0 ^ old_cr0) & X86_CR0_PG) {
                kvm_clear_async_pf_completion_queue(vcpu);
                kvm_async_pf_hash_reset(vcpu);
        }

        if ((cr0 ^ old_cr0) & update_bits)
                kvm_mmu_reset_context(vcpu);

        if (((cr0 ^ old_cr0) & X86_CR0_CD) &&
            kvm_arch_has_noncoherent_dma(vcpu->kvm) &&
            !kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED))
                kvm_zap_gfn_range(vcpu->kvm, 0, ~0ULL);

        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_cr0);

void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw)
{
        (void)kvm_set_cr0(vcpu, kvm_read_cr0_bits(vcpu, ~0x0eul) | (msw & 0x0f));
}
EXPORT_SYMBOL_GPL(kvm_lmsw);

void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu)
{
        if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE)) {

                if (vcpu->arch.xcr0 != host_xcr0)
                        xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0);

                if (vcpu->arch.xsaves_enabled &&
                    vcpu->arch.ia32_xss != host_xss)
                        wrmsrl(MSR_IA32_XSS, vcpu->arch.ia32_xss);
        }

        if (static_cpu_has(X86_FEATURE_PKU) &&
            (kvm_read_cr4_bits(vcpu, X86_CR4_PKE) ||
             (vcpu->arch.xcr0 & XFEATURE_MASK_PKRU)) &&
            vcpu->arch.pkru != vcpu->arch.host_pkru)
                __write_pkru(vcpu->arch.pkru);
}
EXPORT_SYMBOL_GPL(kvm_load_guest_xsave_state);

void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu)
{
        if (static_cpu_has(X86_FEATURE_PKU) &&
            (kvm_read_cr4_bits(vcpu, X86_CR4_PKE) ||
             (vcpu->arch.xcr0 & XFEATURE_MASK_PKRU))) {
                vcpu->arch.pkru = rdpkru();
                if (vcpu->arch.pkru != vcpu->arch.host_pkru)
                        __write_pkru(vcpu->arch.host_pkru);
        }

        if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE)) {

                if (vcpu->arch.xcr0 != host_xcr0)
                        xsetbv(XCR_XFEATURE_ENABLED_MASK, host_xcr0);

                if (vcpu->arch.xsaves_enabled &&
                    vcpu->arch.ia32_xss != host_xss)
                        wrmsrl(MSR_IA32_XSS, host_xss);
        }

}
EXPORT_SYMBOL_GPL(kvm_load_host_xsave_state);

static int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
{
        u64 xcr0 = xcr;
        u64 old_xcr0 = vcpu->arch.xcr0;
        u64 valid_bits;

        /* Only support XCR_XFEATURE_ENABLED_MASK(xcr0) now  */
        if (index != XCR_XFEATURE_ENABLED_MASK)
                return 1;
        if (!(xcr0 & XFEATURE_MASK_FP))
                return 1;
        if ((xcr0 & XFEATURE_MASK_YMM) && !(xcr0 & XFEATURE_MASK_SSE))
                return 1;

        /*
         * Do not allow the guest to set bits that we do not support
         * saving.  However, xcr0 bit 0 is always set, even if the
         * emulated CPU does not support XSAVE (see fx_init).
         */
        valid_bits = vcpu->arch.guest_supported_xcr0 | XFEATURE_MASK_FP;
        if (xcr0 & ~valid_bits)
                return 1;

        if ((!(xcr0 & XFEATURE_MASK_BNDREGS)) !=
            (!(xcr0 & XFEATURE_MASK_BNDCSR)))
                return 1;

        if (xcr0 & XFEATURE_MASK_AVX512) {
                if (!(xcr0 & XFEATURE_MASK_YMM))
                        return 1;
                if ((xcr0 & XFEATURE_MASK_AVX512) != XFEATURE_MASK_AVX512)
                        return 1;
        }
        vcpu->arch.xcr0 = xcr0;

        if ((xcr0 ^ old_xcr0) & XFEATURE_MASK_EXTEND)
                kvm_update_cpuid_runtime(vcpu);
        return 0;
}

int kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
{
        if (kvm_x86_ops.get_cpl(vcpu) != 0 ||
            __kvm_set_xcr(vcpu, index, xcr)) {
                kvm_inject_gp(vcpu, 0);
                return 1;
        }
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_xcr);

int kvm_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
        if (cr4 & cr4_reserved_bits)
                return -EINVAL;

        if (cr4 & vcpu->arch.cr4_guest_rsvd_bits)
                return -EINVAL;

        return 0;
}
EXPORT_SYMBOL_GPL(kvm_valid_cr4);

int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
        unsigned long old_cr4 = kvm_read_cr4(vcpu);
        unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE |
                                   X86_CR4_SMEP;
        unsigned long mmu_role_bits = pdptr_bits | X86_CR4_SMAP | X86_CR4_PKE;

        if (kvm_valid_cr4(vcpu, cr4))
                return 1;

        if (is_long_mode(vcpu)) {
                if (!(cr4 & X86_CR4_PAE))
                        return 1;
                if ((cr4 ^ old_cr4) & X86_CR4_LA57)
                        return 1;
        } else if (is_paging(vcpu) && (cr4 & X86_CR4_PAE)
                   && ((cr4 ^ old_cr4) & pdptr_bits)
                   && !load_pdptrs(vcpu, vcpu->arch.walk_mmu,
                                   kvm_read_cr3(vcpu)))
                return 1;

        if ((cr4 & X86_CR4_PCIDE) && !(old_cr4 & X86_CR4_PCIDE)) {
                if (!guest_cpuid_has(vcpu, X86_FEATURE_PCID))
                        return 1;

                /* PCID can not be enabled when cr3[11:0]!=000H or EFER.LMA=0 */
                if ((kvm_read_cr3(vcpu) & X86_CR3_PCID_MASK) || !is_long_mode(vcpu))

                        return 1;
        }

        if (kvm_x86_ops.set_cr4(vcpu, cr4))
                return 1;

        if (((cr4 ^ old_cr4) & mmu_role_bits) ||
            (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)))
                kvm_mmu_reset_context(vcpu);

        if ((cr4 ^ old_cr4) & (X86_CR4_OSXSAVE | X86_CR4_PKE))
                kvm_update_cpuid_runtime(vcpu);

        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_cr4);

int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
{
        bool skip_tlb_flush = false;
#ifdef CONFIG_X86_64
        bool pcid_enabled = kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE);

        if (pcid_enabled) {
                skip_tlb_flush = cr3 & X86_CR3_PCID_NOFLUSH;
                cr3 &= ~X86_CR3_PCID_NOFLUSH;
        }
#endif

        if (cr3 == kvm_read_cr3(vcpu) && !pdptrs_changed(vcpu)) {
                if (!skip_tlb_flush) {
                        kvm_mmu_sync_roots(vcpu);
                        kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu);
                }
                return 0;
        }

        if (is_long_mode(vcpu) &&
            (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63)))
                return 1;
        else if (is_pae_paging(vcpu) &&
                 !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
                return 1;

        kvm_mmu_new_pgd(vcpu, cr3, skip_tlb_flush, skip_tlb_flush);
        vcpu->arch.cr3 = cr3;
        kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);

        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_cr3);

int kvm_set_cr8(struct kvm_vcpu *vcpu, unsigned long cr8)
{
        if (cr8 & CR8_RESERVED_BITS)
                return 1;
        if (lapic_in_kernel(vcpu))
                kvm_lapic_set_tpr(vcpu, cr8);
        else
                vcpu->arch.cr8 = cr8;
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_cr8);

unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu)
{
        if (lapic_in_kernel(vcpu))
                return kvm_lapic_get_cr8(vcpu);
        else
                return vcpu->arch.cr8;
}
EXPORT_SYMBOL_GPL(kvm_get_cr8);

static void kvm_update_dr0123(struct kvm_vcpu *vcpu)
{
        int i;

        if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) {
                for (i = 0; i < KVM_NR_DB_REGS; i++)
                        vcpu->arch.eff_db[i] = vcpu->arch.db[i];
                vcpu->arch.switch_db_regs |= KVM_DEBUGREG_RELOAD;
        }
}

void kvm_update_dr7(struct kvm_vcpu *vcpu)
{
        unsigned long dr7;

        if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
                dr7 = vcpu->arch.guest_debug_dr7;
        else
                dr7 = vcpu->arch.dr7;
        kvm_x86_ops.set_dr7(vcpu, dr7);
        vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_BP_ENABLED;
        if (dr7 & DR7_BP_EN_MASK)
                vcpu->arch.switch_db_regs |= KVM_DEBUGREG_BP_ENABLED;
}
EXPORT_SYMBOL_GPL(kvm_update_dr7);

static u64 kvm_dr6_fixed(struct kvm_vcpu *vcpu)
{
        u64 fixed = DR6_FIXED_1;

        if (!guest_cpuid_has(vcpu, X86_FEATURE_RTM))
                fixed |= DR6_RTM;
        return fixed;
}

static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
{
        size_t size = ARRAY_SIZE(vcpu->arch.db);

        switch (dr) {
        case 0 ... 3:
                vcpu->arch.db[array_index_nospec(dr, size)] = val;
                if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
                        vcpu->arch.eff_db[dr] = val;
                break;
        case 4:
        case 6:
                if (!kvm_dr6_valid(val))
                        return -1; /* #GP */
                vcpu->arch.dr6 = (val & DR6_VOLATILE) | kvm_dr6_fixed(vcpu);
                break;
        case 5:
        default: /* 7 */
                if (!kvm_dr7_valid(val))
                        return -1; /* #GP */
                vcpu->arch.dr7 = (val & DR7_VOLATILE) | DR7_FIXED_1;
                kvm_update_dr7(vcpu);
                break;
        }

        return 0;
}

int kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
{
        if (__kvm_set_dr(vcpu, dr, val)) {
                kvm_inject_gp(vcpu, 0);
                return 1;
        }
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_dr);

int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
{
        size_t size = ARRAY_SIZE(vcpu->arch.db);

        switch (dr) {
        case 0 ... 3:
                *val = vcpu->arch.db[array_index_nospec(dr, size)];
                break;
        case 4:
        case 6:
                *val = vcpu->arch.dr6;
                break;
        case 5:
        default: /* 7 */
                *val = vcpu->arch.dr7;
                break;
        }
        return 0;
}
EXPORT_SYMBOL_GPL(kvm_get_dr);

bool kvm_rdpmc(struct kvm_vcpu *vcpu)
{
        u32 ecx = kvm_rcx_read(vcpu);
        u64 data;
        int err;

        err = kvm_pmu_rdpmc(vcpu, ecx, &data);
        if (err)
                return err;
        kvm_rax_write(vcpu, (u32)data);
        kvm_rdx_write(vcpu, data >> 32);
        return err;
}
EXPORT_SYMBOL_GPL(kvm_rdpmc);

/*
 * List of msr numbers which we expose to userspace through KVM_GET_MSRS
 * and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.
 *
 * The three MSR lists(msrs_to_save, emulated_msrs, msr_based_features)
 * extract the supported MSRs from the related const lists.
 * msrs_to_save is selected from the msrs_to_save_all to reflect the
 * capabilities of the host cpu. This capabilities test skips MSRs that are
 * kvm-specific. Those are put in emulated_msrs_all; filtering of emulated_msrs
 * may depend on host virtualization features rather than host cpu features.
 */

static const u32 msrs_to_save_all[] = {
        MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
        MSR_STAR,
#ifdef CONFIG_X86_64
        MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
#endif
        MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
        MSR_IA32_FEAT_CTL, MSR_IA32_BNDCFGS, MSR_TSC_AUX,
        MSR_IA32_SPEC_CTRL,
        MSR_IA32_RTIT_CTL, MSR_IA32_RTIT_STATUS, MSR_IA32_RTIT_CR3_MATCH,
        MSR_IA32_RTIT_OUTPUT_BASE, MSR_IA32_RTIT_OUTPUT_MASK,
        MSR_IA32_RTIT_ADDR0_A, MSR_IA32_RTIT_ADDR0_B,
        MSR_IA32_RTIT_ADDR1_A, MSR_IA32_RTIT_ADDR1_B,
        MSR_IA32_RTIT_ADDR2_A, MSR_IA32_RTIT_ADDR2_B,
        MSR_IA32_RTIT_ADDR3_A, MSR_IA32_RTIT_ADDR3_B,
        MSR_IA32_UMWAIT_CONTROL,

        MSR_ARCH_PERFMON_FIXED_CTR0, MSR_ARCH_PERFMON_FIXED_CTR1,
        MSR_ARCH_PERFMON_FIXED_CTR0 + 2, MSR_ARCH_PERFMON_FIXED_CTR0 + 3,
        MSR_CORE_PERF_FIXED_CTR_CTRL, MSR_CORE_PERF_GLOBAL_STATUS,
        MSR_CORE_PERF_GLOBAL_CTRL, MSR_CORE_PERF_GLOBAL_OVF_CTRL,
        MSR_ARCH_PERFMON_PERFCTR0, MSR_ARCH_PERFMON_PERFCTR1,
        MSR_ARCH_PERFMON_PERFCTR0 + 2, MSR_ARCH_PERFMON_PERFCTR0 + 3,
        MSR_ARCH_PERFMON_PERFCTR0 + 4, MSR_ARCH_PERFMON_PERFCTR0 + 5,
        MSR_ARCH_PERFMON_PERFCTR0 + 6, MSR_ARCH_PERFMON_PERFCTR0 + 7,
        MSR_ARCH_PERFMON_PERFCTR0 + 8, MSR_ARCH_PERFMON_PERFCTR0 + 9,
        MSR_ARCH_PERFMON_PERFCTR0 + 10, MSR_ARCH_PERFMON_PERFCTR0 + 11,
        MSR_ARCH_PERFMON_PERFCTR0 + 12, MSR_ARCH_PERFMON_PERFCTR0 + 13,
        MSR_ARCH_PERFMON_PERFCTR0 + 14, MSR_ARCH_PERFMON_PERFCTR0 + 15,
        MSR_ARCH_PERFMON_PERFCTR0 + 16, MSR_ARCH_PERFMON_PERFCTR0 + 17,
        MSR_ARCH_PERFMON_EVENTSEL0, MSR_ARCH_PERFMON_EVENTSEL1,
        MSR_ARCH_PERFMON_EVENTSEL0 + 2, MSR_ARCH_PERFMON_EVENTSEL0 + 3,
        MSR_ARCH_PERFMON_EVENTSEL0 + 4, MSR_ARCH_PERFMON_EVENTSEL0 + 5,
        MSR_ARCH_PERFMON_EVENTSEL0 + 6, MSR_ARCH_PERFMON_EVENTSEL0 + 7,
        MSR_ARCH_PERFMON_EVENTSEL0 + 8, MSR_ARCH_PERFMON_EVENTSEL0 + 9,
        MSR_ARCH_PERFMON_EVENTSEL0 + 10, MSR_ARCH_PERFMON_EVENTSEL0 + 11,
        MSR_ARCH_PERFMON_EVENTSEL0 + 12, MSR_ARCH_PERFMON_EVENTSEL0 + 13,
        MSR_ARCH_PERFMON_EVENTSEL0 + 14, MSR_ARCH_PERFMON_EVENTSEL0 + 15,
        MSR_ARCH_PERFMON_EVENTSEL0 + 16, MSR_ARCH_PERFMON_EVENTSEL0 + 17,
};

static u32 msrs_to_save[ARRAY_SIZE(msrs_to_save_all)];
static unsigned num_msrs_to_save;

static const u32 emulated_msrs_all[] = {
        MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
        MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
        HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
        HV_X64_MSR_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC,
        HV_X64_MSR_TSC_FREQUENCY, HV_X64_MSR_APIC_FREQUENCY,
        HV_X64_MSR_CRASH_P0, HV_X64_MSR_CRASH_P1, HV_X64_MSR_CRASH_P2,
        HV_X64_MSR_CRASH_P3, HV_X64_MSR_CRASH_P4, HV_X64_MSR_CRASH_CTL,
        HV_X64_MSR_RESET,
        HV_X64_MSR_VP_INDEX,
        HV_X64_MSR_VP_RUNTIME,
        HV_X64_MSR_SCONTROL,
        HV_X64_MSR_STIMER0_CONFIG,
        HV_X64_MSR_VP_ASSIST_PAGE,
        HV_X64_MSR_REENLIGHTENMENT_CONTROL, HV_X64_MSR_TSC_EMULATION_CONTROL,
        HV_X64_MSR_TSC_EMULATION_STATUS,
        HV_X64_MSR_SYNDBG_OPTIONS,
        HV_X64_MSR_SYNDBG_CONTROL, HV_X64_MSR_SYNDBG_STATUS,
        HV_X64_MSR_SYNDBG_SEND_BUFFER, HV_X64_MSR_SYNDBG_RECV_BUFFER,
        HV_X64_MSR_SYNDBG_PENDING_BUFFER,

        MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
        MSR_KVM_PV_EOI_EN, MSR_KVM_ASYNC_PF_INT, MSR_KVM_ASYNC_PF_ACK,

        MSR_IA32_TSC_ADJUST,
        MSR_IA32_TSCDEADLINE,
        MSR_IA32_ARCH_CAPABILITIES,
        MSR_IA32_PERF_CAPABILITIES,
        MSR_IA32_MISC_ENABLE,
        MSR_IA32_MCG_STATUS,
        MSR_IA32_MCG_CTL,
        MSR_IA32_MCG_EXT_CTL,
        MSR_IA32_SMBASE,
        MSR_SMI_COUNT,
        MSR_PLATFORM_INFO,
        MSR_MISC_FEATURES_ENABLES,
        MSR_AMD64_VIRT_SPEC_CTRL,
        MSR_IA32_POWER_CTL,
        MSR_IA32_UCODE_REV,

        /*
         * The following list leaves out MSRs whose values are determined
         * by arch/x86/kvm/vmx/nested.c based on CPUID or other MSRs.
         * We always support the "true" VMX control MSRs, even if the host
         * processor does not, so I am putting these registers here rather
         * than in msrs_to_save_all.
         */
        MSR_IA32_VMX_BASIC,
        MSR_IA32_VMX_TRUE_PINBASED_CTLS,
        MSR_IA32_VMX_TRUE_PROCBASED_CTLS,
        MSR_IA32_VMX_TRUE_EXIT_CTLS,
        MSR_IA32_VMX_TRUE_ENTRY_CTLS,
        MSR_IA32_VMX_MISC,
        MSR_IA32_VMX_CR0_FIXED0,
        MSR_IA32_VMX_CR4_FIXED0,
        MSR_IA32_VMX_VMCS_ENUM,
        MSR_IA32_VMX_PROCBASED_CTLS2,
        MSR_IA32_VMX_EPT_VPID_CAP,
        MSR_IA32_VMX_VMFUNC,

        MSR_K7_HWCR,
        MSR_KVM_POLL_CONTROL,
};

static u32 emulated_msrs[ARRAY_SIZE(emulated_msrs_all)];
static unsigned num_emulated_msrs;

/*
 * List of msr numbers which are used to expose MSR-based features that
 * can be used by a hypervisor to validate requested CPU features.
 */
static const u32 msr_based_features_all[] = {
        MSR_IA32_VMX_BASIC,
        MSR_IA32_VMX_TRUE_PINBASED_CTLS,
        MSR_IA32_VMX_PINBASED_CTLS,
        MSR_IA32_VMX_TRUE_PROCBASED_CTLS,
        MSR_IA32_VMX_PROCBASED_CTLS,
        MSR_IA32_VMX_TRUE_EXIT_CTLS,
        MSR_IA32_VMX_EXIT_CTLS,
        MSR_IA32_VMX_TRUE_ENTRY_CTLS,
        MSR_IA32_VMX_ENTRY_CTLS,
        MSR_IA32_VMX_MISC,
        MSR_IA32_VMX_CR0_FIXED0,
        MSR_IA32_VMX_CR0_FIXED1,
        MSR_IA32_VMX_CR4_FIXED0,
        MSR_IA32_VMX_CR4_FIXED1,
        MSR_IA32_VMX_VMCS_ENUM,
        MSR_IA32_VMX_PROCBASED_CTLS2,
        MSR_IA32_VMX_EPT_VPID_CAP,
        MSR_IA32_VMX_VMFUNC,

        MSR_F10H_DECFG,
        MSR_IA32_UCODE_REV,
        MSR_IA32_ARCH_CAPABILITIES,
        MSR_IA32_PERF_CAPABILITIES,
};

static u32 msr_based_features[ARRAY_SIZE(msr_based_features_all)];
static unsigned int num_msr_based_features;

static u64 kvm_get_arch_capabilities(void)
{
        u64 data = 0;

        if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES))
                rdmsrl(MSR_IA32_ARCH_CAPABILITIES, data);

        /*
         * If nx_huge_pages is enabled, KVM's shadow paging will ensure that
         * the nested hypervisor runs with NX huge pages.  If it is not,
         * L1 is anyway vulnerable to ITLB_MULTIHIT explots from other
         * L1 guests, so it need not worry about its own (L2) guests.
         */
        data |= ARCH_CAP_PSCHANGE_MC_NO;

        /*
         * If we're doing cache flushes (either "always" or "cond")
         * we will do one whenever the guest does a vmlaunch/vmresume.
         * If an outer hypervisor is doing the cache flush for us
         * (VMENTER_L1D_FLUSH_NESTED_VM), we can safely pass that
         * capability to the guest too, and if EPT is disabled we're not
         * vulnerable.  Overall, only VMENTER_L1D_FLUSH_NEVER will
         * require a nested hypervisor to do a flush of its own.
         */
        if (l1tf_vmx_mitigation != VMENTER_L1D_FLUSH_NEVER)
                data |= ARCH_CAP_SKIP_VMENTRY_L1DFLUSH;

        if (!boot_cpu_has_bug(X86_BUG_CPU_MELTDOWN))
                data |= ARCH_CAP_RDCL_NO;
        if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS))
                data |= ARCH_CAP_SSB_NO;
        if (!boot_cpu_has_bug(X86_BUG_MDS))
                data |= ARCH_CAP_MDS_NO;

        /*
         * On TAA affected systems:
         *      - nothing to do if TSX is disabled on the host.
         *      - we emulate TSX_CTRL if present on the host.
         *        This lets the guest use VERW to clear CPU buffers.
         */
        if (!boot_cpu_has(X86_FEATURE_RTM))
                data &= ~(ARCH_CAP_TAA_NO | ARCH_CAP_TSX_CTRL_MSR);
        else if (!boot_cpu_has_bug(X86_BUG_TAA))
                data |= ARCH_CAP_TAA_NO;

        return data;
}

static int kvm_get_msr_feature(struct kvm_msr_entry *msr)
{
        switch (msr->index) {
        case MSR_IA32_ARCH_CAPABILITIES:
                msr->data = kvm_get_arch_capabilities();
                break;
        case MSR_IA32_UCODE_REV:
                rdmsrl_safe(msr->index, &msr->data);
                break;
        default:
                return kvm_x86_ops.get_msr_feature(msr);
        }
        return 0;
}

static int do_get_msr_feature(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
{
        struct kvm_msr_entry msr;
        int r;

        msr.index = index;
        r = kvm_get_msr_feature(&msr);

        if (r == KVM_MSR_RET_INVALID) {
                /* Unconditionally clear the output for simplicity */
                *data = 0;
                r = kvm_msr_ignored_check(vcpu, index, 0, false);
        }

        if (r)
                return r;

        *data = msr.data;

        return 0;
}

static bool __kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer)
{
        if (efer & EFER_FFXSR && !guest_cpuid_has(vcpu, X86_FEATURE_FXSR_OPT))
                return false;

        if (efer & EFER_SVME && !guest_cpuid_has(vcpu, X86_FEATURE_SVM))
                return false;

        if (efer & (EFER_LME | EFER_LMA) &&
            !guest_cpuid_has(vcpu, X86_FEATURE_LM))
                return false;

        if (efer & EFER_NX && !guest_cpuid_has(vcpu, X86_FEATURE_NX))
                return false;

        return true;

}
bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer)
{
        if (efer & efer_reserved_bits)
                return false;

        return __kvm_valid_efer(vcpu, efer);
}
EXPORT_SYMBOL_GPL(kvm_valid_efer);

static int set_efer(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
        u64 old_efer = vcpu->arch.efer;
        u64 efer = msr_info->data;

        if (efer & efer_reserved_bits)
                return 1;

        if (!msr_info->host_initiated) {
                if (!__kvm_valid_efer(vcpu, efer))
                        return 1;

                if (is_paging(vcpu) &&
                    (vcpu->arch.efer & EFER_LME) != (efer & EFER_LME))
                        return 1;
        }

        efer &= ~EFER_LMA;
        efer |= vcpu->arch.efer & EFER_LMA;

        kvm_x86_ops.set_efer(vcpu, efer);

        /* Update reserved bits */
        if ((efer ^ old_efer) & EFER_NX)
                kvm_mmu_reset_context(vcpu);

        return 0;
}

void kvm_enable_efer_bits(u64 mask)
{
       efer_reserved_bits &= ~mask;
}
EXPORT_SYMBOL_GPL(kvm_enable_efer_bits);

/*
 * Write @data into the MSR specified by @index.  Select MSR specific fault
 * checks are bypassed if @host_initiated is %true.
 * Returns 0 on success, non-0 otherwise.
 * Assumes vcpu_load() was already called.
 */
static int __kvm_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data,
                         bool host_initiated)
{
        struct msr_data msr;

        switch (index) {
        case MSR_FS_BASE:
        case MSR_GS_BASE:
        case MSR_KERNEL_GS_BASE:
        case MSR_CSTAR:
        case MSR_LSTAR:
                if (is_noncanonical_address(data, vcpu))
                        return 1;
                break;
        case MSR_IA32_SYSENTER_EIP:
        case MSR_IA32_SYSENTER_ESP:
                /*
                 * IA32_SYSENTER_ESP and IA32_SYSENTER_EIP cause #GP if
                 * non-canonical address is written on Intel but not on
                 * AMD (which ignores the top 32-bits, because it does
                 * not implement 64-bit SYSENTER).
                 *
                 * 64-bit code should hence be able to write a non-canonical
                 * value on AMD.  Making the address canonical ensures that
                 * vmentry does not fail on Intel after writing a non-canonical
                 * value, and that something deterministic happens if the guest
                 * invokes 64-bit SYSENTER.
                 */
                data = get_canonical(data, vcpu_virt_addr_bits(vcpu));
        }

        msr.data = data;
        msr.index = index;
        msr.host_initiated = host_initiated;

        return kvm_x86_ops.set_msr(vcpu, &msr);
}

static int kvm_set_msr_ignored_check(struct kvm_vcpu *vcpu,
                                     u32 index, u64 data, bool host_initiated)
{
        int ret = __kvm_set_msr(vcpu, index, data, host_initiated);

        if (ret == KVM_MSR_RET_INVALID)
                ret = kvm_msr_ignored_check(vcpu, index, data, true);

        return ret;
}

/*
 * Read the MSR specified by @index into @data.  Select MSR specific fault
 * checks are bypassed if @host_initiated is %true.
 * Returns 0 on success, non-0 otherwise.
 * Assumes vcpu_load() was already called.
 */
int __kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data,
                  bool host_initiated)
{
        struct msr_data msr;
        int ret;

        msr.index = index;
        msr.host_initiated = host_initiated;

        ret = kvm_x86_ops.get_msr(vcpu, &msr);
        if (!ret)
                *data = msr.data;
        return ret;
}

static int kvm_get_msr_ignored_check(struct kvm_vcpu *vcpu,
                                     u32 index, u64 *data, bool host_initiated)
{
        int ret = __kvm_get_msr(vcpu, index, data, host_initiated);

        if (ret == KVM_MSR_RET_INVALID) {
                /* Unconditionally clear *data for simplicity */
                *data = 0;
                ret = kvm_msr_ignored_check(vcpu, index, 0, false);
        }

        return ret;
}

int kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data)
{
        return kvm_get_msr_ignored_check(vcpu, index, data, false);
}
EXPORT_SYMBOL_GPL(kvm_get_msr);

int kvm_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data)
{
        return kvm_set_msr_ignored_check(vcpu, index, data, false);
}
EXPORT_SYMBOL_GPL(kvm_set_msr);

int kvm_emulate_rdmsr(struct kvm_vcpu *vcpu)
{
        u32 ecx = kvm_rcx_read(vcpu);
        u64 data;

        if (kvm_get_msr(vcpu, ecx, &data)) {
                trace_kvm_msr_read_ex(ecx);
                kvm_inject_gp(vcpu, 0);
                return 1;
        }

        trace_kvm_msr_read(ecx, data);

        kvm_rax_write(vcpu, data & -1u);
        kvm_rdx_write(vcpu, (data >> 32) & -1u);
        return kvm_skip_emulated_instruction(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_emulate_rdmsr);

int kvm_emulate_wrmsr(struct kvm_vcpu *vcpu)
{
        u32 ecx = kvm_rcx_read(vcpu);
        u64 data = kvm_read_edx_eax(vcpu);

        if (kvm_set_msr(vcpu, ecx, data)) {
                trace_kvm_msr_write_ex(ecx, data);
                kvm_inject_gp(vcpu, 0);
                return 1;
        }

        trace_kvm_msr_write(ecx, data);
        return kvm_skip_emulated_instruction(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_emulate_wrmsr);

bool kvm_vcpu_exit_request(struct kvm_vcpu *vcpu)
{
        return vcpu->mode == EXITING_GUEST_MODE || kvm_request_pending(vcpu) ||
                xfer_to_guest_mode_work_pending();
}
EXPORT_SYMBOL_GPL(kvm_vcpu_exit_request);

/*
 * The fast path for frequent and performance sensitive wrmsr emulation,
 * i.e. the sending of IPI, sending IPI early in the VM-Exit flow reduces
 * the latency of virtual IPI by avoiding the expensive bits of transitioning
 * from guest to host, e.g. reacquiring KVM's SRCU lock. In contrast to the
 * other cases which must be called after interrupts are enabled on the host.
 */
static int handle_fastpath_set_x2apic_icr_irqoff(struct kvm_vcpu *vcpu, u64 data)
{
        if (!lapic_in_kernel(vcpu) || !apic_x2apic_mode(vcpu->arch.apic))
                return 1;

        if (((data & APIC_SHORT_MASK) == APIC_DEST_NOSHORT) &&
                ((data & APIC_DEST_MASK) == APIC_DEST_PHYSICAL) &&
                ((data & APIC_MODE_MASK) == APIC_DM_FIXED) &&
                ((u32)(data >> 32) != X2APIC_BROADCAST)) {

                data &= ~(1 << 12);
                kvm_apic_send_ipi(vcpu->arch.apic, (u32)data, (u32)(data >> 32));
                kvm_lapic_set_reg(vcpu->arch.apic, APIC_ICR2, (u32)(data >> 32));
                kvm_lapic_set_reg(vcpu->arch.apic, APIC_ICR, (u32)data);
                trace_kvm_apic_write(APIC_ICR, (u32)data);
                return 0;
        }

        return 1;
}

static int handle_fastpath_set_tscdeadline(struct kvm_vcpu *vcpu, u64 data)
{
        if (!kvm_can_use_hv_timer(vcpu))
                return 1;

        kvm_set_lapic_tscdeadline_msr(vcpu, data);
        return 0;
}

fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu)
{
        u32 msr = kvm_rcx_read(vcpu);
        u64 data;
        fastpath_t ret = EXIT_FASTPATH_NONE;

        switch (msr) {
        case APIC_BASE_MSR + (APIC_ICR >> 4):
                data = kvm_read_edx_eax(vcpu);
                if (!handle_fastpath_set_x2apic_icr_irqoff(vcpu, data)) {
                        kvm_skip_emulated_instruction(vcpu);
                        ret = EXIT_FASTPATH_EXIT_HANDLED;
                }
                break;
        case MSR_IA32_TSCDEADLINE:
                data = kvm_read_edx_eax(vcpu);
                if (!handle_fastpath_set_tscdeadline(vcpu, data)) {
                        kvm_skip_emulated_instruction(vcpu);
                        ret = EXIT_FASTPATH_REENTER_GUEST;
                }
                break;
        default:
                break;
        }

        if (ret != EXIT_FASTPATH_NONE)
                trace_kvm_msr_write(msr, data);

        return ret;
}
EXPORT_SYMBOL_GPL(handle_fastpath_set_msr_irqoff);

/*
 * Adapt set_msr() to msr_io()'s calling convention
 */
static int do_get_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
{
        return kvm_get_msr_ignored_check(vcpu, index, data, true);
}

static int do_set_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
{
        return kvm_set_msr_ignored_check(vcpu, index, *data, true);
}

#ifdef CONFIG_X86_64
struct pvclock_clock {
        int vclock_mode;
        u64 cycle_last;
        u64 mask;
        u32 mult;
        u32 shift;
        u64 base_cycles;
        u64 offset;
};

struct pvclock_gtod_data {
        seqcount_t      seq;

        struct pvclock_clock clock; /* extract of a clocksource struct */
        struct pvclock_clock raw_clock; /* extract of a clocksource struct */

        ktime_t         offs_boot;
        u64             wall_time_sec;
};

static struct pvclock_gtod_data pvclock_gtod_data;

static void update_pvclock_gtod(struct timekeeper *tk)
{
        struct pvclock_gtod_data *vdata = &pvclock_gtod_data;

        write_seqcount_begin(&vdata->seq);

        /* copy pvclock gtod data */
        vdata->clock.vclock_mode        = tk->tkr_mono.clock->vdso_clock_mode;
        vdata->clock.cycle_last         = tk->tkr_mono.cycle_last;
        vdata->clock.mask               = tk->tkr_mono.mask;
        vdata->clock.mult               = tk->tkr_mono.mult;
        vdata->clock.shift              = tk->tkr_mono.shift;
        vdata->clock.base_cycles        = tk->tkr_mono.xtime_nsec;
        vdata->clock.offset             = tk->tkr_mono.base;

        vdata->raw_clock.vclock_mode    = tk->tkr_raw.clock->vdso_clock_mode;
        vdata->raw_clock.cycle_last     = tk->tkr_raw.cycle_last;
        vdata->raw_clock.mask           = tk->tkr_raw.mask;
        vdata->raw_clock.mult           = tk->tkr_raw.mult;
        vdata->raw_clock.shift          = tk->tkr_raw.shift;
        vdata->raw_clock.base_cycles    = tk->tkr_raw.xtime_nsec;
        vdata->raw_clock.offset         = tk->tkr_raw.base;

        vdata->wall_time_sec            = tk->xtime_sec;

        vdata->offs_boot                = tk->offs_boot;

        write_seqcount_end(&vdata->seq);
}

static s64 get_kvmclock_base_ns(void)
{
        /* Count up from boot time, but with the frequency of the raw clock.  */
        return ktime_to_ns(ktime_add(ktime_get_raw(), pvclock_gtod_data.offs_boot));
}
#else
static s64 get_kvmclock_base_ns(void)
{
        /* Master clock not used, so we can just use CLOCK_BOOTTIME.  */
        return ktime_get_boottime_ns();
}
#endif

void kvm_set_pending_timer(struct kvm_vcpu *vcpu)
{
        kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
        kvm_vcpu_kick(vcpu);
}

static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
{
        int version;
        int r;
        struct pvclock_wall_clock wc;
        u64 wall_nsec;

        if (!wall_clock)
                return;

        r = kvm_read_guest(kvm, wall_clock, &version, sizeof(version));
        if (r)
                return;

        if (version & 1)
                ++version;  /* first time write, random junk */

        ++version;

        if (kvm_write_guest(kvm, wall_clock, &version, sizeof(version)))
                return;

        /*
         * The guest calculates current wall clock time by adding
         * system time (updated by kvm_guest_time_update below) to the
         * wall clock specified here.  We do the reverse here.
         */
        wall_nsec = ktime_get_real_ns() - get_kvmclock_ns(kvm);

        wc.nsec = do_div(wall_nsec, 1000000000);
        wc.sec = (u32)wall_nsec; /* overflow in 2106 guest time */
        wc.version = version;

        kvm_write_guest(kvm, wall_clock, &wc, sizeof(wc));

        version++;
        kvm_write_guest(kvm, wall_clock, &version, sizeof(version));
}

static uint32_t div_frac(uint32_t dividend, uint32_t divisor)
{
        do_shl32_div32(dividend, divisor);
        return dividend;
}

static void kvm_get_time_scale(uint64_t scaled_hz, uint64_t base_hz,
                               s8 *pshift, u32 *pmultiplier)
{
        uint64_t scaled64;
        int32_t  shift = 0;
        uint64_t tps64;
        uint32_t tps32;

        tps64 = base_hz;
        scaled64 = scaled_hz;
        while (tps64 > scaled64*2 || tps64 & 0xffffffff00000000ULL) {
                tps64 >>= 1;
                shift--;
        }

        tps32 = (uint32_t)tps64;
        while (tps32 <= scaled64 || scaled64 & 0xffffffff00000000ULL) {
                if (scaled64 & 0xffffffff00000000ULL || tps32 & 0x80000000)
                        scaled64 >>= 1;
                else
                        tps32 <<= 1;
                shift++;
        }

        *pshift = shift;
        *pmultiplier = div_frac(scaled64, tps32);
}

#ifdef CONFIG_X86_64
static atomic_t kvm_guest_has_master_clock = ATOMIC_INIT(0);
#endif

static DEFINE_PER_CPU(unsigned long, cpu_tsc_khz);
static unsigned long max_tsc_khz;

static u32 adjust_tsc_khz(u32 khz, s32 ppm)
{
        u64 v = (u64)khz * (1000000 + ppm);
        do_div(v, 1000000);
        return v;
}

static int set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
{
        u64 ratio;

        /* Guest TSC same frequency as host TSC? */
        if (!scale) {
                vcpu->arch.tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
                return 0;
        }

        /* TSC scaling supported? */
        if (!kvm_has_tsc_control) {
                if (user_tsc_khz > tsc_khz) {
                        vcpu->arch.tsc_catchup = 1;
                        vcpu->arch.tsc_always_catchup = 1;
                        return 0;
                } else {
                        pr_warn_ratelimited("user requested TSC rate below hardware speed\n");
                        return -1;
                }
        }

        /* TSC scaling required  - calculate ratio */
        ratio = mul_u64_u32_div(1ULL << kvm_tsc_scaling_ratio_frac_bits,
                                user_tsc_khz, tsc_khz);

        if (ratio == 0 || ratio >= kvm_max_tsc_scaling_ratio) {
                pr_warn_ratelimited("Invalid TSC scaling ratio - virtual-tsc-khz=%u\n",
                                    user_tsc_khz);
                return -1;
        }

        vcpu->arch.tsc_scaling_ratio = ratio;
        return 0;
}

static int kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)
{
        u32 thresh_lo, thresh_hi;
        int use_scaling = 0;

        /* tsc_khz can be zero if TSC calibration fails */
        if (user_tsc_khz == 0) {
                /* set tsc_scaling_ratio to a safe value */
                vcpu->arch.tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
                return -1;
        }

        /* Compute a scale to convert nanoseconds in TSC cycles */
        kvm_get_time_scale(user_tsc_khz * 1000LL, NSEC_PER_SEC,
                           &vcpu->arch.virtual_tsc_shift,
                           &vcpu->arch.virtual_tsc_mult);
        vcpu->arch.virtual_tsc_khz = user_tsc_khz;

        /*
         * Compute the variation in TSC rate which is acceptable
         * within the range of tolerance and decide if the
         * rate being applied is within that bounds of the hardware
         * rate.  If so, no scaling or compensation need be done.
         */
        thresh_lo = adjust_tsc_khz(tsc_khz, -tsc_tolerance_ppm);
        thresh_hi = adjust_tsc_khz(tsc_khz, tsc_tolerance_ppm);
        if (user_tsc_khz < thresh_lo || user_tsc_khz > thresh_hi) {
                pr_debug("kvm: requested TSC rate %u falls outside tolerance [%u,%u]\n", user_tsc_khz, thresh_lo, thresh_hi);
                use_scaling = 1;
        }
        return set_tsc_khz(vcpu, user_tsc_khz, use_scaling);
}

static u64 compute_guest_tsc(struct kvm_vcpu *vcpu, s64 kernel_ns)
{
        u64 tsc = pvclock_scale_delta(kernel_ns-vcpu->arch.this_tsc_nsec,
                                      vcpu->arch.virtual_tsc_mult,
                                      vcpu->arch.virtual_tsc_shift);
        tsc += vcpu->arch.this_tsc_write;
        return tsc;
}

static inline int gtod_is_based_on_tsc(int mode)
{
        return mode == VDSO_CLOCKMODE_TSC || mode == VDSO_CLOCKMODE_HVCLOCK;
}

static void kvm_track_tsc_matching(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_X86_64
        bool vcpus_matched;
        struct kvm_arch *ka = &vcpu->kvm->arch;
        struct pvclock_gtod_data *gtod = &pvclock_gtod_data;

        vcpus_matched = (ka->nr_vcpus_matched_tsc + 1 ==
                         atomic_read(&vcpu->kvm->online_vcpus));

        /*
         * Once the masterclock is enabled, always perform request in
         * order to update it.
         *
         * In order to enable masterclock, the host clocksource must be TSC
         * and the vcpus need to have matched TSCs.  When that happens,
         * perform request to enable masterclock.
         */
        if (ka->use_master_clock ||
            (gtod_is_based_on_tsc(gtod->clock.vclock_mode) && vcpus_matched))
                kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);

        trace_kvm_track_tsc(vcpu->vcpu_id, ka->nr_vcpus_matched_tsc,
                            atomic_read(&vcpu->kvm->online_vcpus),
                            ka->use_master_clock, gtod->clock.vclock_mode);
#endif
}

static void update_ia32_tsc_adjust_msr(struct kvm_vcpu *vcpu, s64 offset)
{
        u64 curr_offset = vcpu->arch.l1_tsc_offset;
        vcpu->arch.ia32_tsc_adjust_msr += offset - curr_offset;
}

/*
 * Multiply tsc by a fixed point number represented by ratio.
 *
 * The most significant 64-N bits (mult) of ratio represent the
 * integral part of the fixed point number; the remaining N bits
 * (frac) represent the fractional part, ie. ratio represents a fixed
 * point number (mult + frac * 2^(-N)).
 *
 * N equals to kvm_tsc_scaling_ratio_frac_bits.
 */
static inline u64 __scale_tsc(u64 ratio, u64 tsc)
{
        return mul_u64_u64_shr(tsc, ratio, kvm_tsc_scaling_ratio_frac_bits);

}

u64 kvm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc)
{
        u64 _tsc = tsc;
        u64 ratio = vcpu->arch.tsc_scaling_ratio;

        if (ratio != kvm_default_tsc_scaling_ratio)
                _tsc = __scale_tsc(ratio, tsc);

        return _tsc;
}
EXPORT_SYMBOL_GPL(kvm_scale_tsc);

static u64 kvm_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc)
{
        u64 tsc;

        tsc = kvm_scale_tsc(vcpu, rdtsc());

        return target_tsc - tsc;
}

u64 kvm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc)
{
        return vcpu->arch.l1_tsc_offset + kvm_scale_tsc(vcpu, host_tsc);
}
EXPORT_SYMBOL_GPL(kvm_read_l1_tsc);

static void kvm_vcpu_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
{
        vcpu->arch.l1_tsc_offset = offset;
        vcpu->arch.tsc_offset = kvm_x86_ops.write_l1_tsc_offset(vcpu, offset);
}

static inline bool kvm_check_tsc_unstable(void)
{
#ifdef CONFIG_X86_64
        /*
         * TSC is marked unstable when we're running on Hyper-V,
         * 'TSC page' clocksource is good.
         */
        if (pvclock_gtod_data.clock.vclock_mode == VDSO_CLOCKMODE_HVCLOCK)
                return false;
#endif
        return check_tsc_unstable();
}

void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
{
        struct kvm *kvm = vcpu->kvm;
        u64 offset, ns, elapsed;
        unsigned long flags;
        bool matched;
        bool already_matched;
        u64 data = msr->data;
        bool synchronizing = false;

        raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags);
        offset = kvm_compute_tsc_offset(vcpu, data);
        ns = get_kvmclock_base_ns();
        elapsed = ns - kvm->arch.last_tsc_nsec;

        if (vcpu->arch.virtual_tsc_khz) {
                if (data == 0 && msr->host_initiated) {
                        /*
                         * detection of vcpu initialization -- need to sync
                         * with other vCPUs. This particularly helps to keep
                         * kvm_clock stable after CPU hotplug
                         */
                        synchronizing = true;
                } else {
                        u64 tsc_exp = kvm->arch.last_tsc_write +
                                                nsec_to_cycles(vcpu, elapsed);
                        u64 tsc_hz = vcpu->arch.virtual_tsc_khz * 1000LL;
                        /*
                         * Special case: TSC write with a small delta (1 second)
                         * of virtual cycle time against real time is
                         * interpreted as an attempt to synchronize the CPU.
                         */
                        synchronizing = data < tsc_exp + tsc_hz &&
                                        data + tsc_hz > tsc_exp;
                }
        }

        /*
         * For a reliable TSC, we can match TSC offsets, and for an unstable
         * TSC, we add elapsed time in this computation.  We could let the
         * compensation code attempt to catch up if we fall behind, but
         * it's better to try to match offsets from the beginning.
         */
        if (synchronizing &&
            vcpu->arch.virtual_tsc_khz == kvm->arch.last_tsc_khz) {
                if (!kvm_check_tsc_unstable()) {
                        offset = kvm->arch.cur_tsc_offset;
                } else {
                        u64 delta = nsec_to_cycles(vcpu, elapsed);
                        data += delta;
                        offset = kvm_compute_tsc_offset(vcpu, data);
                }
                matched = true;
                already_matched = (vcpu->arch.this_tsc_generation == kvm->arch.cur_tsc_generation);
        } else {
                /*
                 * We split periods of matched TSC writes into generations.
                 * For each generation, we track the original measured
                 * nanosecond time, offset, and write, so if TSCs are in
                 * sync, we can match exact offset, and if not, we can match
                 * exact software computation in compute_guest_tsc()
                 *
                 * These values are tracked in kvm->arch.cur_xxx variables.
                 */
                kvm->arch.cur_tsc_generation++;
                kvm->arch.cur_tsc_nsec = ns;
                kvm->arch.cur_tsc_write = data;
                kvm->arch.cur_tsc_offset = offset;
                matched = false;
        }

        /*
         * We also track th most recent recorded KHZ, write and time to
         * allow the matching interval to be extended at each write.
         */
        kvm->arch.last_tsc_nsec = ns;
        kvm->arch.last_tsc_write = data;
        kvm->arch.last_tsc_khz = vcpu->arch.virtual_tsc_khz;

        vcpu->arch.last_guest_tsc = data;

        /* Keep track of which generation this VCPU has synchronized to */
        vcpu->arch.this_tsc_generation = kvm->arch.cur_tsc_generation;
        vcpu->arch.this_tsc_nsec = kvm->arch.cur_tsc_nsec;
        vcpu->arch.this_tsc_write = kvm->arch.cur_tsc_write;

        if (!msr->host_initiated && guest_cpuid_has(vcpu, X86_FEATURE_TSC_ADJUST))
                update_ia32_tsc_adjust_msr(vcpu, offset);

        kvm_vcpu_write_tsc_offset(vcpu, offset);
        raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);

        spin_lock(&kvm->arch.pvclock_gtod_sync_lock);
        if (!matched) {
                kvm->arch.nr_vcpus_matched_tsc = 0;
        } else if (!already_matched) {
                kvm->arch.nr_vcpus_matched_tsc++;
        }

        kvm_track_tsc_matching(vcpu);
        spin_unlock(&kvm->arch.pvclock_gtod_sync_lock);
}

EXPORT_SYMBOL_GPL(kvm_write_tsc);

static inline void adjust_tsc_offset_guest(struct kvm_vcpu *vcpu,
                                           s64 adjustment)
{
        u64 tsc_offset = vcpu->arch.l1_tsc_offset;
        kvm_vcpu_write_tsc_offset(vcpu, tsc_offset + adjustment);
}

static inline void adjust_tsc_offset_host(struct kvm_vcpu *vcpu, s64 adjustment)
{
        if (vcpu->arch.tsc_scaling_ratio != kvm_default_tsc_scaling_ratio)
                WARN_ON(adjustment < 0);
        adjustment = kvm_scale_tsc(vcpu, (u64) adjustment);
        adjust_tsc_offset_guest(vcpu, adjustment);
}

#ifdef CONFIG_X86_64

static u64 read_tsc(void)
{
        u64 ret = (u64)rdtsc_ordered();
        u64 last = pvclock_gtod_data.clock.cycle_last;

        if (likely(ret >= last))
                return ret;

        /*
         * GCC likes to generate cmov here, but this branch is extremely
         * predictable (it's just a function of time and the likely is
         * very likely) and there's a data dependence, so force GCC
         * to generate a branch instead.  I don't barrier() because
         * we don't actually need a barrier, and if this function
         * ever gets inlined it will generate worse code.
         */
        asm volatile ("");
        return last;
}

static inline u64 vgettsc(struct pvclock_clock *clock, u64 *tsc_timestamp,
                          int *mode)
{
        long v;
        u64 tsc_pg_val;

        switch (clock->vclock_mode) {
        case VDSO_CLOCKMODE_HVCLOCK:
                tsc_pg_val = hv_read_tsc_page_tsc(hv_get_tsc_page(),
                                                  tsc_timestamp);
                if (tsc_pg_val != U64_MAX) {
                        /* TSC page valid */
                        *mode = VDSO_CLOCKMODE_HVCLOCK;
                        v = (tsc_pg_val - clock->cycle_last) &
                                clock->mask;
                } else {
                        /* TSC page invalid */
                        *mode = VDSO_CLOCKMODE_NONE;
                }
                break;
        case VDSO_CLOCKMODE_TSC:
                *mode = VDSO_CLOCKMODE_TSC;
                *tsc_timestamp = read_tsc();
                v = (*tsc_timestamp - clock->cycle_last) &
                        clock->mask;
                break;
        default:
                *mode = VDSO_CLOCKMODE_NONE;
        }

        if (*mode == VDSO_CLOCKMODE_NONE)
                *tsc_timestamp = v = 0;

        return v * clock->mult;
}

static int do_monotonic_raw(s64 *t, u64 *tsc_timestamp)
{
        struct pvclock_gtod_data *gtod = &pvclock_gtod_data;
        unsigned long seq;
        int mode;
        u64 ns;

        do {
                seq = read_seqcount_begin(&gtod->seq);
                ns = gtod->raw_clock.base_cycles;
                ns += vgettsc(&gtod->raw_clock, tsc_timestamp, &mode);
                ns >>= gtod->raw_clock.shift;
                ns += ktime_to_ns(ktime_add(gtod->raw_clock.offset, gtod->offs_boot));
        } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
        *t = ns;

        return mode;
}

static int do_realtime(struct timespec64 *ts, u64 *tsc_timestamp)
{
        struct pvclock_gtod_data *gtod = &pvclock_gtod_data;
        unsigned long seq;
        int mode;
        u64 ns;

        do {
                seq = read_seqcount_begin(&gtod->seq);
                ts->tv_sec = gtod->wall_time_sec;
                ns = gtod->clock.base_cycles;
                ns += vgettsc(&gtod->clock, tsc_timestamp, &mode);
                ns >>= gtod->clock.shift;
        } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));

        ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
        ts->tv_nsec = ns;

        return mode;
}

/* returns true if host is using TSC based clocksource */
static bool kvm_get_time_and_clockread(s64 *kernel_ns, u64 *tsc_timestamp)
{
        /* checked again under seqlock below */
        if (!gtod_is_based_on_tsc(pvclock_gtod_data.clock.vclock_mode))
                return false;

        return gtod_is_based_on_tsc(do_monotonic_raw(kernel_ns,
                                                      tsc_timestamp));
}

/* returns true if host is using TSC based clocksource */
static bool kvm_get_walltime_and_clockread(struct timespec64 *ts,
                                           u64 *tsc_timestamp)
{
        /* checked again under seqlock below */
        if (!gtod_is_based_on_tsc(pvclock_gtod_data.clock.vclock_mode))
                return false;

        return gtod_is_based_on_tsc(do_realtime(ts, tsc_timestamp));
}
#endif

/*
 *
 * Assuming a stable TSC across physical CPUS, and a stable TSC
 * across virtual CPUs, the following condition is possible.
 * Each numbered line represents an event visible to both
 * CPUs at the next numbered event.
 *
 * "timespecX" represents host monotonic time. "tscX" represents
 * RDTSC value.
 *
 *              VCPU0 on CPU0           |       VCPU1 on CPU1
 *
 * 1.  read timespec0,tsc0
 * 2.                                   | timespec1 = timespec0 + N
 *                                      | tsc1 = tsc0 + M
 * 3. transition to guest               | transition to guest
 * 4. ret0 = timespec0 + (rdtsc - tsc0) |
 * 5.                                   | ret1 = timespec1 + (rdtsc - tsc1)
 *                                      | ret1 = timespec0 + N + (rdtsc - (tsc0 + M))
 *
 * Since ret0 update is visible to VCPU1 at time 5, to obey monotonicity:
 *
 *      - ret0 < ret1
 *      - timespec0 + (rdtsc - tsc0) < timespec0 + N + (rdtsc - (tsc0 + M))
 *              ...
 *      - 0 < N - M => M < N
 *
 * That is, when timespec0 != timespec1, M < N. Unfortunately that is not
 * always the case (the difference between two distinct xtime instances
 * might be smaller then the difference between corresponding TSC reads,
 * when updating guest vcpus pvclock areas).
 *
 * To avoid that problem, do not allow visibility of distinct
 * system_timestamp/tsc_timestamp values simultaneously: use a master
 * copy of host monotonic time values. Update that master copy
 * in lockstep.
 *
 * Rely on synchronization of host TSCs and guest TSCs for monotonicity.
 *
 */

static void pvclock_update_vm_gtod_copy(struct kvm *kvm)
{
#ifdef CONFIG_X86_64
        struct kvm_arch *ka = &kvm->arch;
        int vclock_mode;
        bool host_tsc_clocksource, vcpus_matched;

        vcpus_matched = (ka->nr_vcpus_matched_tsc + 1 ==
                        atomic_read(&kvm->online_vcpus));

        /*
         * If the host uses TSC clock, then passthrough TSC as stable
         * to the guest.
         */
        host_tsc_clocksource = kvm_get_time_and_clockread(
                                        &ka->master_kernel_ns,
                                        &ka->master_cycle_now);

        ka->use_master_clock = host_tsc_clocksource && vcpus_matched
                                && !ka->backwards_tsc_observed
                                && !ka->boot_vcpu_runs_old_kvmclock;

        if (ka->use_master_clock)
                atomic_set(&kvm_guest_has_master_clock, 1);

        vclock_mode = pvclock_gtod_data.clock.vclock_mode;
        trace_kvm_update_master_clock(ka->use_master_clock, vclock_mode,
                                        vcpus_matched);
#endif
}

void kvm_make_mclock_inprogress_request(struct kvm *kvm)
{
        kvm_make_all_cpus_request(kvm, KVM_REQ_MCLOCK_INPROGRESS);
}

static void kvm_gen_update_masterclock(struct kvm *kvm)
{
#ifdef CONFIG_X86_64
        int i;
        struct kvm_vcpu *vcpu;
        struct kvm_arch *ka = &kvm->arch;

        spin_lock(&ka->pvclock_gtod_sync_lock);
        kvm_make_mclock_inprogress_request(kvm);
        /* no guest entries from this point */
        pvclock_update_vm_gtod_copy(kvm);

        kvm_for_each_vcpu(i, vcpu, kvm)
                kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);

        /* guest entries allowed */
        kvm_for_each_vcpu(i, vcpu, kvm)
                kvm_clear_request(KVM_REQ_MCLOCK_INPROGRESS, vcpu);

        spin_unlock(&ka->pvclock_gtod_sync_lock);
#endif
}

u64 get_kvmclock_ns(struct kvm *kvm)
{
        struct kvm_arch *ka = &kvm->arch;
        struct pvclock_vcpu_time_info hv_clock;
        u64 ret;

        spin_lock(&ka->pvclock_gtod_sync_lock);
        if (!ka->use_master_clock) {
                spin_unlock(&ka->pvclock_gtod_sync_lock);
                return get_kvmclock_base_ns() + ka->kvmclock_offset;
        }

        hv_clock.tsc_timestamp = ka->master_cycle_now;
        hv_clock.system_time = ka->master_kernel_ns + ka->kvmclock_offset;
        spin_unlock(&ka->pvclock_gtod_sync_lock);

        /* both __this_cpu_read() and rdtsc() should be on the same cpu */
        get_cpu();

        if (__this_cpu_read(cpu_tsc_khz)) {
                kvm_get_time_scale(NSEC_PER_SEC, __this_cpu_read(cpu_tsc_khz) * 1000LL,
                                   &hv_clock.tsc_shift,
                                   &hv_clock.tsc_to_system_mul);
                ret = __pvclock_read_cycles(&hv_clock, rdtsc());
        } else
                ret = get_kvmclock_base_ns() + ka->kvmclock_offset;

        put_cpu();

        return ret;
}

static void kvm_setup_pvclock_page(struct kvm_vcpu *v)
{
        struct kvm_vcpu_arch *vcpu = &v->arch;
        struct pvclock_vcpu_time_info guest_hv_clock;

        if (unlikely(kvm_read_guest_cached(v->kvm, &vcpu->pv_time,
                &guest_hv_clock, sizeof(guest_hv_clock))))
                return;

        /* This VCPU is paused, but it's legal for a guest to read another
         * VCPU's kvmclock, so we really have to follow the specification where
         * it says that version is odd if data is being modified, and even after
         * it is consistent.
         *
         * Version field updates must be kept separate.  This is because
         * kvm_write_guest_cached might use a "rep movs" instruction, and
         * writes within a string instruction are weakly ordered.  So there
         * are three writes overall.
         *
         * As a small optimization, only write the version field in the first
         * and third write.  The vcpu->pv_time cache is still valid, because the
         * version field is the first in the struct.
         */
        BUILD_BUG_ON(offsetof(struct pvclock_vcpu_time_info, version) != 0);

        if (guest_hv_clock.version & 1)
                ++guest_hv_clock.version;  /* first time write, random junk */

        vcpu->hv_clock.version = guest_hv_clock.version + 1;
        kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
                                &vcpu->hv_clock,
                                sizeof(vcpu->hv_clock.version));

        smp_wmb();

        /* retain PVCLOCK_GUEST_STOPPED if set in guest copy */
        vcpu->hv_clock.flags |= (guest_hv_clock.flags & PVCLOCK_GUEST_STOPPED);

        if (vcpu->pvclock_set_guest_stopped_request) {
                vcpu->hv_clock.flags |= PVCLOCK_GUEST_STOPPED;
                vcpu->pvclock_set_guest_stopped_request = false;
        }

        trace_kvm_pvclock_update(v->vcpu_id, &vcpu->hv_clock);

        kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
                                &vcpu->hv_clock,
                                sizeof(vcpu->hv_clock));

        smp_wmb();

        vcpu->hv_clock.version++;
        kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
                                &vcpu->hv_clock,
                                sizeof(vcpu->hv_clock.version));
}

static int kvm_guest_time_update(struct kvm_vcpu *v)
{
        unsigned long flags, tgt_tsc_khz;
        struct kvm_vcpu_arch *vcpu = &v->arch;
        struct kvm_arch *ka = &v->kvm->arch;
        s64 kernel_ns;
        u64 tsc_timestamp, host_tsc;
        u8 pvclock_flags;
        bool use_master_clock;

        kernel_ns = 0;
        host_tsc = 0;

        /*
         * If the host uses TSC clock, then passthrough TSC as stable
         * to the guest.
         */
        spin_lock(&ka->pvclock_gtod_sync_lock);
        use_master_clock = ka->use_master_clock;
        if (use_master_clock) {
                host_tsc = ka->master_cycle_now;
                kernel_ns = ka->master_kernel_ns;
        }
        spin_unlock(&ka->pvclock_gtod_sync_lock);

        /* Keep irq disabled to prevent changes to the clock */
        local_irq_save(flags);
        tgt_tsc_khz = __this_cpu_read(cpu_tsc_khz);
        if (unlikely(tgt_tsc_khz == 0)) {
                local_irq_restore(flags);
                kvm_make_request(KVM_REQ_CLOCK_UPDATE, v);
                return 1;
        }
        if (!use_master_clock) {
                host_tsc = rdtsc();
                kernel_ns = get_kvmclock_base_ns();
        }

        tsc_timestamp = kvm_read_l1_tsc(v, host_tsc);

        /*
         * We may have to catch up the TSC to match elapsed wall clock
         * time for two reasons, even if kvmclock is used.
         *   1) CPU could have been running below the maximum TSC rate
         *   2) Broken TSC compensation resets the base at each VCPU
         *      entry to avoid unknown leaps of TSC even when running
         *      again on the same CPU.  This may cause apparent elapsed
         *      time to disappear, and the guest to stand still or run
         *      very slowly.
         */
        if (vcpu->tsc_catchup) {
                u64 tsc = compute_guest_tsc(v, kernel_ns);
                if (tsc > tsc_timestamp) {
                        adjust_tsc_offset_guest(v, tsc - tsc_timestamp);
                        tsc_timestamp = tsc;
                }
        }

        local_irq_restore(flags);

        /* With all the info we got, fill in the values */

        if (kvm_has_tsc_control)
                tgt_tsc_khz = kvm_scale_tsc(v, tgt_tsc_khz);

        if (unlikely(vcpu->hw_tsc_khz != tgt_tsc_khz)) {
                kvm_get_time_scale(NSEC_PER_SEC, tgt_tsc_khz * 1000LL,
                                   &vcpu->hv_clock.tsc_shift,
                                   &vcpu->hv_clock.tsc_to_system_mul);
                vcpu->hw_tsc_khz = tgt_tsc_khz;
        }

        vcpu->hv_clock.tsc_timestamp = tsc_timestamp;
        vcpu->hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset;
        vcpu->last_guest_tsc = tsc_timestamp;

        /* If the host uses TSC clocksource, then it is stable */
        pvclock_flags = 0;
        if (use_master_clock)
                pvclock_flags |= PVCLOCK_TSC_STABLE_BIT;

        vcpu->hv_clock.flags = pvclock_flags;

        if (vcpu->pv_time_enabled)
                kvm_setup_pvclock_page(v);
        if (v == kvm_get_vcpu(v->kvm, 0))
                kvm_hv_setup_tsc_page(v->kvm, &vcpu->hv_clock);
        return 0;
}

/*
 * kvmclock updates which are isolated to a given vcpu, such as
 * vcpu->cpu migration, should not allow system_timestamp from
 * the rest of the vcpus to remain static. Otherwise ntp frequency
 * correction applies to one vcpu's system_timestamp but not
 * the others.
 *
 * So in those cases, request a kvmclock update for all vcpus.
 * We need to rate-limit these requests though, as they can
 * considerably slow guests that have a large number of vcpus.
 * The time for a remote vcpu to update its kvmclock is bound
 * by the delay we use to rate-limit the updates.
 */

#define KVMCLOCK_UPDATE_DELAY msecs_to_jiffies(100)

static void kvmclock_update_fn(struct work_struct *work)
{
        int i;
        struct delayed_work *dwork = to_delayed_work(work);
        struct kvm_arch *ka = container_of(dwork, struct kvm_arch,
                                           kvmclock_update_work);
        struct kvm *kvm = container_of(ka, struct kvm, arch);
        struct kvm_vcpu *vcpu;

        kvm_for_each_vcpu(i, vcpu, kvm) {
                kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
                kvm_vcpu_kick(vcpu);
        }
}

static void kvm_gen_kvmclock_update(struct kvm_vcpu *v)
{
        struct kvm *kvm = v->kvm;

        kvm_make_request(KVM_REQ_CLOCK_UPDATE, v);
        schedule_delayed_work(&kvm->arch.kvmclock_update_work,
                                        KVMCLOCK_UPDATE_DELAY);
}

#define KVMCLOCK_SYNC_PERIOD (300 * HZ)

static void kvmclock_sync_fn(struct work_struct *work)
{
        struct delayed_work *dwork = to_delayed_work(work);
        struct kvm_arch *ka = container_of(dwork, struct kvm_arch,
                                           kvmclock_sync_work);
        struct kvm *kvm = container_of(ka, struct kvm, arch);

        if (!kvmclock_periodic_sync)
                return;

        schedule_delayed_work(&kvm->arch.kvmclock_update_work, 0);
        schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
                                        KVMCLOCK_SYNC_PERIOD);
}

/*
 * On AMD, HWCR[McStatusWrEn] controls whether setting MCi_STATUS results in #GP.
 */
static bool can_set_mci_status(struct kvm_vcpu *vcpu)
{
        /* McStatusWrEn enabled? */
        if (guest_cpuid_is_amd_or_hygon(vcpu))
                return !!(vcpu->arch.msr_hwcr & BIT_ULL(18));

        return false;
}

static int set_msr_mce(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
        u64 mcg_cap = vcpu->arch.mcg_cap;
        unsigned bank_num = mcg_cap & 0xff;
        u32 msr = msr_info->index;
        u64 data = msr_info->data;

        switch (msr) {
        case MSR_IA32_MCG_STATUS:
                vcpu->arch.mcg_status = data;
                break;
        case MSR_IA32_MCG_CTL:
                if (!(mcg_cap & MCG_CTL_P) &&
                    (data || !msr_info->host_initiated))
                        return 1;
                if (data != 0 && data != ~(u64)0)
                        return 1;
                vcpu->arch.mcg_ctl = data;
                break;
        default:
                if (msr >= MSR_IA32_MC0_CTL &&
                    msr < MSR_IA32_MCx_CTL(bank_num)) {
                        u32 offset = array_index_nospec(
                                msr - MSR_IA32_MC0_CTL,
                                MSR_IA32_MCx_CTL(bank_num) - MSR_IA32_MC0_CTL);

                        /* only 0 or all 1s can be written to IA32_MCi_CTL
                         * some Linux kernels though clear bit 10 in bank 4 to
                         * workaround a BIOS/GART TBL issue on AMD K8s, ignore
                         * this to avoid an uncatched #GP in the guest
                         */
                        if ((offset & 0x3) == 0 &&
                            data != 0 && (data | (1 << 10)) != ~(u64)0)
                                return -1;

                        /* MCi_STATUS */
                        if (!msr_info->host_initiated &&
                            (offset & 0x3) == 1 && data != 0) {
                                if (!can_set_mci_status(vcpu))
                                        return -1;
                        }

                        vcpu->arch.mce_banks[offset] = data;
                        break;
                }
                return 1;
        }
        return 0;
}

static int xen_hvm_config(struct kvm_vcpu *vcpu, u64 data)
{
        struct kvm *kvm = vcpu->kvm;
        int lm = is_long_mode(vcpu);
        u8 *blob_addr = lm ? (u8 *)(long)kvm->arch.xen_hvm_config.blob_addr_64
                : (u8 *)(long)kvm->arch.xen_hvm_config.blob_addr_32;
        u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64
                : kvm->arch.xen_hvm_config.blob_size_32;
        u32 page_num = data & ~PAGE_MASK;
        u64 page_addr = data & PAGE_MASK;
        u8 *page;
        int r;

        r = -E2BIG;
        if (page_num >= blob_size)
                goto out;
        r = -ENOMEM;
        page = memdup_user(blob_addr + (page_num * PAGE_SIZE), PAGE_SIZE);
        if (IS_ERR(page)) {
                r = PTR_ERR(page);
                goto out;
        }
        if (kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE))
                goto out_free;
        r = 0;
out_free:
        kfree(page);
out:
        return r;
}

static inline bool kvm_pv_async_pf_enabled(struct kvm_vcpu *vcpu)
{
        u64 mask = KVM_ASYNC_PF_ENABLED | KVM_ASYNC_PF_DELIVERY_AS_INT;

        return (vcpu->arch.apf.msr_en_val & mask) == mask;
}

static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data)
{
        gpa_t gpa = data & ~0x3f;

        /* Bits 4:5 are reserved, Should be zero */
        if (data & 0x30)
                return 1;

        if (!lapic_in_kernel(vcpu))
                return data ? 1 : 0;

        vcpu->arch.apf.msr_en_val = data;

        if (!kvm_pv_async_pf_enabled(vcpu)) {
                kvm_clear_async_pf_completion_queue(vcpu);
                kvm_async_pf_hash_reset(vcpu);
                return 0;
        }

        if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.apf.data, gpa,
                                        sizeof(u64)))
                return 1;

        vcpu->arch.apf.send_user_only = !(data & KVM_ASYNC_PF_SEND_ALWAYS);
        vcpu->arch.apf.delivery_as_pf_vmexit = data & KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT;

        kvm_async_pf_wakeup_all(vcpu);

        return 0;
}

static int kvm_pv_enable_async_pf_int(struct kvm_vcpu *vcpu, u64 data)
{
        /* Bits 8-63 are reserved */
        if (data >> 8)
                return 1;

        if (!lapic_in_kernel(vcpu))
                return 1;

        vcpu->arch.apf.msr_int_val = data;

        vcpu->arch.apf.vec = data & KVM_ASYNC_PF_VEC_MASK;

        return 0;
}

static void kvmclock_reset(struct kvm_vcpu *vcpu)
{
        vcpu->arch.pv_time_enabled = false;
        vcpu->arch.time = 0;
}

static void kvm_vcpu_flush_tlb_all(struct kvm_vcpu *vcpu)
{
        ++vcpu->stat.tlb_flush;
        kvm_x86_ops.tlb_flush_all(vcpu);
}

static void kvm_vcpu_flush_tlb_guest(struct kvm_vcpu *vcpu)
{
        ++vcpu->stat.tlb_flush;
        kvm_x86_ops.tlb_flush_guest(vcpu);
}

static void record_steal_time(struct kvm_vcpu *vcpu)
{
        struct kvm_host_map map;
        struct kvm_steal_time *st;

        if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
                return;

        /* -EAGAIN is returned in atomic context so we can just return. */
        if (kvm_map_gfn(vcpu, vcpu->arch.st.msr_val >> PAGE_SHIFT,
                        &map, &vcpu->arch.st.cache, false))
                return;

        st = map.hva +
                offset_in_page(vcpu->arch.st.msr_val & KVM_STEAL_VALID_BITS);

        /*
         * Doing a TLB flush here, on the guest's behalf, can avoid
         * expensive IPIs.
         */
        trace_kvm_pv_tlb_flush(vcpu->vcpu_id,
                st->preempted & KVM_VCPU_FLUSH_TLB);
        if (xchg(&st->preempted, 0) & KVM_VCPU_FLUSH_TLB)
                kvm_vcpu_flush_tlb_guest(vcpu);

        vcpu->arch.st.preempted = 0;

        if (st->version & 1)
                st->version += 1;  /* first time write, random junk */

        st->version += 1;

        smp_wmb();

        st->steal += current->sched_info.run_delay -
                vcpu->arch.st.last_steal;
        vcpu->arch.st.last_steal = current->sched_info.run_delay;

        smp_wmb();

        st->version += 1;

        kvm_unmap_gfn(vcpu, &map, &vcpu->arch.st.cache, true, false);
}

int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
        bool pr = false;
        u32 msr = msr_info->index;
        u64 data = msr_info->data;

        switch (msr) {
        case MSR_AMD64_NB_CFG:
        case MSR_IA32_UCODE_WRITE:
        case MSR_VM_HSAVE_PA:
        case MSR_AMD64_PATCH_LOADER:
        case MSR_AMD64_BU_CFG2:
        case MSR_AMD64_DC_CFG:
        case MSR_F15H_EX_CFG:
                break;

        case MSR_IA32_UCODE_REV:
                if (msr_info->host_initiated)
                        vcpu->arch.microcode_version = data;
                break;
        case MSR_IA32_ARCH_CAPABILITIES:
                if (!msr_info->host_initiated)
                        return 1;
                vcpu->arch.arch_capabilities = data;
                break;
        case MSR_IA32_PERF_CAPABILITIES: {
                struct kvm_msr_entry msr_ent = {.index = msr, .data = 0};

                if (!msr_info->host_initiated)
                        return 1;
                if (guest_cpuid_has(vcpu, X86_FEATURE_PDCM) && kvm_get_msr_feature(&msr_ent))
                        return 1;
                if (data & ~msr_ent.data)
                        return 1;

                vcpu->arch.perf_capabilities = data;

                return 0;
                }
        case MSR_EFER:
                return set_efer(vcpu, msr_info);
        case MSR_K7_HWCR:
                data &= ~(u64)0x40;     /* ignore flush filter disable */
                data &= ~(u64)0x100;    /* ignore ignne emulation enable */
                data &= ~(u64)0x8;      /* ignore TLB cache disable */

                /* Handle McStatusWrEn */
                if (data == BIT_ULL(18)) {
                        vcpu->arch.msr_hwcr = data;
                } else if (data != 0) {
                        vcpu_unimpl(vcpu, "unimplemented HWCR wrmsr: 0x%llx\n",
                                    data);
                        return 1;
                }
                break;
        case MSR_FAM10H_MMIO_CONF_BASE:
                if (data != 0) {
                        vcpu_unimpl(vcpu, "unimplemented MMIO_CONF_BASE wrmsr: "
                                    "0x%llx\n", data);
                        return 1;
                }
                break;
        case MSR_IA32_DEBUGCTLMSR:
                if (!data) {
                        /* We support the non-activated case already */
                        break;
                } else if (data & ~(DEBUGCTLMSR_LBR | DEBUGCTLMSR_BTF)) {
                        /* Values other than LBR and BTF are vendor-specific,
                           thus reserved and should throw a #GP */
                        return 1;
                }
                vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
                            __func__, data);
                break;
        case 0x200 ... 0x2ff:
                return kvm_mtrr_set_msr(vcpu, msr, data);
        case MSR_IA32_APICBASE:
                return kvm_set_apic_base(vcpu, msr_info);
        case APIC_BASE_MSR ... APIC_BASE_MSR + 0xff:
                return kvm_x2apic_msr_write(vcpu, msr, data);
        case MSR_IA32_TSCDEADLINE:
                kvm_set_lapic_tscdeadline_msr(vcpu, data);
                break;
        case MSR_IA32_TSC_ADJUST:
                if (guest_cpuid_has(vcpu, X86_FEATURE_TSC_ADJUST)) {
                        if (!msr_info->host_initiated) {
                                s64 adj = data - vcpu->arch.ia32_tsc_adjust_msr;
                                adjust_tsc_offset_guest(vcpu, adj);
                        }
                        vcpu->arch.ia32_tsc_adjust_msr = data;
                }
                break;
        case MSR_IA32_MISC_ENABLE:
                if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT) &&
                    ((vcpu->arch.ia32_misc_enable_msr ^ data) & MSR_IA32_MISC_ENABLE_MWAIT)) {
                        if (!guest_cpuid_has(vcpu, X86_FEATURE_XMM3))
                                return 1;
                        vcpu->arch.ia32_misc_enable_msr = data;
                        kvm_update_cpuid_runtime(vcpu);
                } else {
                        vcpu->arch.ia32_misc_enable_msr = data;
                }
                break;
        case MSR_IA32_SMBASE:
                if (!msr_info->host_initiated)
                        return 1;
                vcpu->arch.smbase = data;
                break;
        case MSR_IA32_POWER_CTL:
                vcpu->arch.msr_ia32_power_ctl = data;
                break;
        case MSR_IA32_TSC:
                kvm_write_tsc(vcpu, msr_info);
                break;
        case MSR_IA32_XSS:
                if (!msr_info->host_initiated &&
                    !guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))
                        return 1;
                /*
                 * KVM supports exposing PT to the guest, but does not support
                 * IA32_XSS[bit 8]. Guests have to use RDMSR/WRMSR rather than
                 * XSAVES/XRSTORS to save/restore PT MSRs.
                 */
                if (data & ~supported_xss)
                        return 1;
                vcpu->arch.ia32_xss = data;
                break;
        case MSR_SMI_COUNT:
                if (!msr_info->host_initiated)
                        return 1;
                vcpu->arch.smi_count = data;
                break;
        case MSR_KVM_WALL_CLOCK_NEW:
        case MSR_KVM_WALL_CLOCK:
                vcpu->kvm->arch.wall_clock = data;
                kvm_write_wall_clock(vcpu->kvm, data);
                break;
        case MSR_KVM_SYSTEM_TIME_NEW:
        case MSR_KVM_SYSTEM_TIME: {
                struct kvm_arch *ka = &vcpu->kvm->arch;

                if (vcpu->vcpu_id == 0 && !msr_info->host_initiated) {
                        bool tmp = (msr == MSR_KVM_SYSTEM_TIME);

                        if (ka->boot_vcpu_runs_old_kvmclock != tmp)
                                kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);

                        ka->boot_vcpu_runs_old_kvmclock = tmp;
                }

                vcpu->arch.time = data;
                kvm_make_request(KVM_REQ_GLOBAL_CLOCK_UPDATE, vcpu);

                /* we verify if the enable bit is set... */
                vcpu->arch.pv_time_enabled = false;
                if (!(data & 1))
                        break;

                if (!kvm_gfn_to_hva_cache_init(vcpu->kvm,
                     &vcpu->arch.pv_time, data & ~1ULL,
                     sizeof(struct pvclock_vcpu_time_info)))
                        vcpu->arch.pv_time_enabled = true;

                break;
        }