// SPDX-License-Identifier: GPL-2.0-only
/*
 * HyperV  Detection code.
 *
 * Copyright (C) 2010, Novell, Inc.
 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
 */

#include <linux/types.h>
#include <linux/time.h>
#include <linux/clocksource.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/hardirq.h>
#include <linux/efi.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kexec.h>
#include <linux/random.h>
#include <asm/processor.h>
#include <asm/hypervisor.h>
#include <hyperv/hvhdk.h>
#include <asm/mshyperv.h>
#include <asm/desc.h>
#include <asm/idtentry.h>
#include <asm/irq_regs.h>
#include <asm/i8259.h>
#include <asm/apic.h>
#include <asm/timer.h>
#include <asm/reboot.h>
#include <asm/msr.h>
#include <asm/nmi.h>
#include <clocksource/hyperv_timer.h>
#include <asm/numa.h>
#include <asm/svm.h>

/* Is Linux running on nested Microsoft Hypervisor */
bool hv_nested;
struct ms_hyperv_info ms_hyperv;

#if IS_ENABLED(CONFIG_HYPERV)
/*
 * When running with the paravisor, controls proxying the synthetic interrupts
 * from the host
 */
static bool hv_para_sint_proxy;

static inline unsigned int hv_get_nested_msr(unsigned int reg)
{
        if (hv_is_sint_msr(reg))
                return reg - HV_X64_MSR_SINT0 + HV_X64_MSR_NESTED_SINT0;

        switch (reg) {
        case HV_X64_MSR_SIMP:
                return HV_X64_MSR_NESTED_SIMP;
        case HV_X64_MSR_SIEFP:
                return HV_X64_MSR_NESTED_SIEFP;
        case HV_X64_MSR_SVERSION:
                return HV_X64_MSR_NESTED_SVERSION;
        case HV_X64_MSR_SCONTROL:
                return HV_X64_MSR_NESTED_SCONTROL;
        case HV_X64_MSR_EOM:
                return HV_X64_MSR_NESTED_EOM;
        default:
                return reg;
        }
}

u64 hv_get_non_nested_msr(unsigned int reg)
{
        u64 value;

        if (hv_is_synic_msr(reg) && ms_hyperv.paravisor_present)
                hv_ivm_msr_read(reg, &value);
        else
                rdmsrq(reg, value);
        return value;
}
EXPORT_SYMBOL_GPL(hv_get_non_nested_msr);

void hv_set_non_nested_msr(unsigned int reg, u64 value)
{
        if (hv_is_synic_msr(reg) && ms_hyperv.paravisor_present) {
                /* The hypervisor will get the intercept. */
                hv_ivm_msr_write(reg, value);

                /* Using wrmsrq so the following goes to the paravisor. */
                if (hv_is_sint_msr(reg)) {
                        union hv_synic_sint sint = { .as_uint64 = value };

                        sint.proxy = hv_para_sint_proxy;
                        native_wrmsrq(reg, sint.as_uint64);
                }
        } else {
                native_wrmsrq(reg, value);
        }
}
EXPORT_SYMBOL_GPL(hv_set_non_nested_msr);

/*
 * Enable or disable proxying synthetic interrupts
 * to the paravisor.
 */
void hv_para_set_sint_proxy(bool enable)
{
        hv_para_sint_proxy = enable;
}

/*
 * Get the SynIC register value from the paravisor.
 */
u64 hv_para_get_synic_register(unsigned int reg)
{
        if (WARN_ON(!ms_hyperv.paravisor_present || !hv_is_synic_msr(reg)))
                return ~0ULL;
        return native_read_msr(reg);
}

/*
 * Set the SynIC register value with the paravisor.
 */
void hv_para_set_synic_register(unsigned int reg, u64 val)
{
        if (WARN_ON(!ms_hyperv.paravisor_present || !hv_is_synic_msr(reg)))
                return;
        native_write_msr(reg, val);
}

u64 hv_get_msr(unsigned int reg)
{
        if (hv_nested)
                reg = hv_get_nested_msr(reg);

        return hv_get_non_nested_msr(reg);
}
EXPORT_SYMBOL_GPL(hv_get_msr);

void hv_set_msr(unsigned int reg, u64 value)
{
        if (hv_nested)
                reg = hv_get_nested_msr(reg);

        hv_set_non_nested_msr(reg, value);
}
EXPORT_SYMBOL_GPL(hv_set_msr);

static void (*mshv_handler)(void);
static void (*vmbus_handler)(void);
static void (*hv_stimer0_handler)(void);
static void (*hv_kexec_handler)(void);
static void (*hv_crash_handler)(struct pt_regs *regs);

DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_callback)
{
        struct pt_regs *old_regs = set_irq_regs(regs);

        inc_irq_stat(irq_hv_callback_count);
        if (mshv_handler)
                mshv_handler();

        if (vmbus_handler)
                vmbus_handler();

        if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED)
                apic_eoi();

        set_irq_regs(old_regs);
}

void hv_setup_mshv_handler(void (*handler)(void))
{
        mshv_handler = handler;
}

void hv_setup_vmbus_handler(void (*handler)(void))
{
        vmbus_handler = handler;
}

void hv_remove_vmbus_handler(void)
{
        /* We have no way to deallocate the interrupt gate */
        vmbus_handler = NULL;
}

/*
 * Routines to do per-architecture handling of stimer0
 * interrupts when in Direct Mode
 */
DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0)
{
        struct pt_regs *old_regs = set_irq_regs(regs);

        inc_irq_stat(hyperv_stimer0_count);
        if (hv_stimer0_handler)
                hv_stimer0_handler();
        add_interrupt_randomness(HYPERV_STIMER0_VECTOR);
        apic_eoi();

        set_irq_regs(old_regs);
}

/* For x86/x64, override weak placeholders in hyperv_timer.c */
void hv_setup_stimer0_handler(void (*handler)(void))
{
        hv_stimer0_handler = handler;
}

void hv_remove_stimer0_handler(void)
{
        /* We have no way to deallocate the interrupt gate */
        hv_stimer0_handler = NULL;
}

void hv_setup_kexec_handler(void (*handler)(void))
{
        hv_kexec_handler = handler;
}

void hv_remove_kexec_handler(void)
{
        hv_kexec_handler = NULL;
}

void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
{
        hv_crash_handler = handler;
}

void hv_remove_crash_handler(void)
{
        hv_crash_handler = NULL;
}

#ifdef CONFIG_KEXEC_CORE
static void hv_machine_shutdown(void)
{
        if (kexec_in_progress && hv_kexec_handler)
                hv_kexec_handler();

        /*
         * Call hv_cpu_die() on all the CPUs, otherwise later the hypervisor
         * corrupts the old VP Assist Pages and can crash the kexec kernel.
         */
        if (kexec_in_progress)
                cpuhp_remove_state(CPUHP_AP_HYPERV_ONLINE);

        /* The function calls stop_other_cpus(). */
        native_machine_shutdown();

        /* Disable the hypercall page when there is only 1 active CPU. */
        if (kexec_in_progress)
                hyperv_cleanup();
}
#endif /* CONFIG_KEXEC_CORE */

#ifdef CONFIG_CRASH_DUMP
static void hv_guest_crash_shutdown(struct pt_regs *regs)
{
        if (hv_crash_handler)
                hv_crash_handler(regs);

        /* The function calls crash_smp_send_stop(). */
        native_machine_crash_shutdown(regs);

        /* Disable the hypercall page when there is only 1 active CPU. */
        hyperv_cleanup();
}
#endif /* CONFIG_CRASH_DUMP */

static u64 hv_ref_counter_at_suspend;
static void (*old_save_sched_clock_state)(void);
static void (*old_restore_sched_clock_state)(void);

/*
 * Hyper-V clock counter resets during hibernation. Save and restore clock
 * offset during suspend/resume, while also considering the time passed
 * before suspend. This is to make sure that sched_clock using hv tsc page
 * based clocksource, proceeds from where it left off during suspend and
 * it shows correct time for the timestamps of kernel messages after resume.
 */
static void save_hv_clock_tsc_state(void)
{
        hv_ref_counter_at_suspend = hv_read_reference_counter();
}

static void restore_hv_clock_tsc_state(void)
{
        /*
         * Adjust the offsets used by hv tsc clocksource to
         * account for the time spent before hibernation.
         * adjusted value = reference counter (time) at suspend
         *                - reference counter (time) now.
         */
        hv_adj_sched_clock_offset(hv_ref_counter_at_suspend - hv_read_reference_counter());
}

/*
 * Functions to override save_sched_clock_state and restore_sched_clock_state
 * functions of x86_platform. The Hyper-V clock counter is reset during
 * suspend-resume and the offset used to measure time needs to be
 * corrected, post resume.
 */
static void hv_save_sched_clock_state(void)
{
        old_save_sched_clock_state();
        save_hv_clock_tsc_state();
}

static void hv_restore_sched_clock_state(void)
{
        restore_hv_clock_tsc_state();
        old_restore_sched_clock_state();
}

static void __init x86_setup_ops_for_tsc_pg_clock(void)
{
        if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
                return;

        old_save_sched_clock_state = x86_platform.save_sched_clock_state;
        x86_platform.save_sched_clock_state = hv_save_sched_clock_state;

        old_restore_sched_clock_state = x86_platform.restore_sched_clock_state;
        x86_platform.restore_sched_clock_state = hv_restore_sched_clock_state;
}

#ifdef CONFIG_X86_64
DEFINE_STATIC_CALL(hv_hypercall, hv_std_hypercall);
EXPORT_STATIC_CALL_TRAMP_GPL(hv_hypercall);
#define hypercall_update(hc) static_call_update(hv_hypercall, hc)
#endif
#endif /* CONFIG_HYPERV */

#ifndef hypercall_update
#define hypercall_update(hc) (void)hc
#endif

static uint32_t  __init ms_hyperv_platform(void)
{
        u32 eax;
        u32 hyp_signature[3];

        if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
                return 0;

        cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
              &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);

        if (eax < HYPERV_CPUID_MIN || eax > HYPERV_CPUID_MAX ||
            memcmp("Microsoft Hv", hyp_signature, 12))
                return 0;

        /* HYPERCALL and VP_INDEX MSRs are mandatory for all features. */
        eax = cpuid_eax(HYPERV_CPUID_FEATURES);
        if (!(eax & HV_MSR_HYPERCALL_AVAILABLE)) {
                pr_warn("x86/hyperv: HYPERCALL MSR not available.\n");
                return 0;
        }
        if (!(eax & HV_MSR_VP_INDEX_AVAILABLE)) {
                pr_warn("x86/hyperv: VP_INDEX MSR not available.\n");
                return 0;
        }

        return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
}

#ifdef CONFIG_X86_LOCAL_APIC
/*
 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
 * it difficult to process CHANNELMSG_UNLOAD in case of crash. Handle
 * unknown NMI on the first CPU which gets it.
 */
static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
{
        static atomic_t nmi_cpu = ATOMIC_INIT(-1);
        unsigned int old_cpu, this_cpu;

        if (!unknown_nmi_panic)
                return NMI_DONE;

        old_cpu = -1;
        this_cpu = raw_smp_processor_id();
        if (!atomic_try_cmpxchg(&nmi_cpu, &old_cpu, this_cpu))
                return NMI_HANDLED;

        return NMI_DONE;
}
#endif

static unsigned long hv_get_tsc_khz(void)
{
        unsigned long freq;

        rdmsrq(HV_X64_MSR_TSC_FREQUENCY, freq);

        return freq / 1000;
}

#if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV)
static void __init hv_smp_prepare_boot_cpu(void)
{
        native_smp_prepare_boot_cpu();
#if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS)
        hv_init_spinlocks();
#endif
}

static void __init hv_smp_prepare_cpus(unsigned int max_cpus)
{
#ifdef CONFIG_X86_64
        int i;
        int ret;
#endif

        native_smp_prepare_cpus(max_cpus);

        /*
         *  Override wakeup_secondary_cpu_64 callback for SEV-SNP
         *  enlightened guest.
         */
        if (!ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
                apic->wakeup_secondary_cpu_64 = hv_snp_boot_ap;
                return;
        }

#ifdef CONFIG_X86_64
        for_each_present_cpu(i) {
                if (i == 0)
                        continue;
                ret = hv_call_add_logical_proc(numa_cpu_node(i), i, cpu_physical_id(i));
                BUG_ON(ret);
        }

        for_each_present_cpu(i) {
                if (i == 0)
                        continue;
                ret = hv_call_create_vp(numa_cpu_node(i), hv_current_partition_id, i, i);
                BUG_ON(ret);
        }
#endif
}
#endif

/*
 * When a fully enlightened TDX VM runs on Hyper-V, the firmware sets the
 * HW_REDUCED flag: refer to acpi_tb_create_local_fadt(). Consequently ttyS0
 * interrupts can't work because request_irq() -> ... -> irq_to_desc() returns
 * NULL for ttyS0. This happens because mp_config_acpi_legacy_irqs() sees a
 * nr_legacy_irqs() of 0, so it doesn't initialize the array 'mp_irqs[]', and
 * later setup_IO_APIC_irqs() -> find_irq_entry() fails to find the legacy irqs
 * from the array and hence doesn't create the necessary irq description info.
 *
 * Clone arch/x86/kernel/acpi/boot.c: acpi_generic_reduced_hw_init() here,
 * except don't change 'legacy_pic', which keeps its default value
 * 'default_legacy_pic'. This way, mp_config_acpi_legacy_irqs() sees a non-zero
 * nr_legacy_irqs() and eventually serial console interrupts works properly.
 */
static void __init reduced_hw_init(void)
{
        x86_init.timers.timer_init      = x86_init_noop;
        x86_init.irqs.pre_vector_init   = x86_init_noop;
}

int hv_get_hypervisor_version(union hv_hypervisor_version_info *info)
{
        unsigned int hv_max_functions;

        hv_max_functions = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS);
        if (hv_max_functions < HYPERV_CPUID_VERSION) {
                pr_err("%s: Could not detect Hyper-V version\n", __func__);
                return -ENODEV;
        }

        cpuid(HYPERV_CPUID_VERSION, &info->eax, &info->ebx, &info->ecx, &info->edx);

        return 0;
}
EXPORT_SYMBOL_GPL(hv_get_hypervisor_version);

/*
 * Reserved vectors hard coded in the hypervisor. If used outside, the hypervisor
 * will either crash or hang or attempt to break into debugger.
 */
static void hv_reserve_irq_vectors(void)
{
        #define HYPERV_DBG_FASTFAIL_VECTOR      0x29
        #define HYPERV_DBG_ASSERT_VECTOR        0x2C
        #define HYPERV_DBG_SERVICE_VECTOR       0x2D

        if (cpu_feature_enabled(X86_FEATURE_FRED))
                return;

        if (test_and_set_bit(HYPERV_DBG_ASSERT_VECTOR, system_vectors) ||
            test_and_set_bit(HYPERV_DBG_SERVICE_VECTOR, system_vectors) ||
            test_and_set_bit(HYPERV_DBG_FASTFAIL_VECTOR, system_vectors))
                BUG();

        pr_info("Hyper-V: reserve vectors: 0x%x 0x%x 0x%x\n",
                HYPERV_DBG_ASSERT_VECTOR, HYPERV_DBG_SERVICE_VECTOR,
                HYPERV_DBG_FASTFAIL_VECTOR);
}

static void __init ms_hyperv_init_platform(void)
{
        int hv_max_functions_eax, eax;

#ifdef CONFIG_PARAVIRT
        pv_info.name = "Hyper-V";
#endif

        /*
         * Extract the features and hints
         */
        ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
        ms_hyperv.priv_high = cpuid_ebx(HYPERV_CPUID_FEATURES);
        ms_hyperv.ext_features = cpuid_ecx(HYPERV_CPUID_FEATURES);
        ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
        ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);

        hv_max_functions_eax = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS);

        pr_info("Hyper-V: privilege flags low %#x, high %#x, ext %#x, hints %#x, misc %#x\n",
                ms_hyperv.features, ms_hyperv.priv_high,
                ms_hyperv.ext_features, ms_hyperv.hints,
                ms_hyperv.misc_features);

        ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);
        ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS);

        pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
                 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);

        hv_identify_partition_type();

        if (hv_root_partition())
                hv_reserve_irq_vectors();

        if (cc_platform_has(CC_ATTR_SNP_SECURE_AVIC))
                ms_hyperv.hints |= HV_DEPRECATING_AEOI_RECOMMENDED;

        if (ms_hyperv.hints & HV_X64_HYPERV_NESTED) {
                hv_nested = true;
                pr_info("Hyper-V: running on a nested hypervisor\n");
        }

        /*
         * There is no check against the max function for HYPERV_CPUID_VIRT_STACK_* CPUID
         * leaves as the hypervisor doesn't handle them. Even a nested root partition (L2
         * root) will not get them because the nested (L1) hypervisor filters them out.
         * These are handled through intercept processing by the Windows Hyper-V stack
         * or the paravisor.
         */
        eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_PROPERTIES);
        ms_hyperv.confidential_vmbus_available =
                eax & HYPERV_VS_PROPERTIES_EAX_CONFIDENTIAL_VMBUS_AVAILABLE;
        ms_hyperv.msi_ext_dest_id =
                eax & HYPERV_VS_PROPERTIES_EAX_EXTENDED_IOAPIC_RTE;

        if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
            ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
                x86_platform.calibrate_tsc = hv_get_tsc_khz;
                x86_platform.calibrate_cpu = hv_get_tsc_khz;
                setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
        }

        if (ms_hyperv.priv_high & HV_ISOLATION) {
                ms_hyperv.isolation_config_a = cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG);
                ms_hyperv.isolation_config_b = cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG);

                if (ms_hyperv.shared_gpa_boundary_active)
                        ms_hyperv.shared_gpa_boundary =
                                BIT_ULL(ms_hyperv.shared_gpa_boundary_bits);

                pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
                        ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);


                if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) {
                        static_branch_enable(&isolation_type_snp);
                        if (!ms_hyperv.paravisor_present)
                                hypercall_update(hv_snp_hypercall);
                } else if (hv_get_isolation_type() == HV_ISOLATION_TYPE_TDX) {
                        static_branch_enable(&isolation_type_tdx);

                        /* A TDX VM must use x2APIC and doesn't use lazy EOI. */
                        ms_hyperv.hints &= ~HV_X64_APIC_ACCESS_RECOMMENDED;

                        if (!ms_hyperv.paravisor_present) {
                                hypercall_update(hv_tdx_hypercall);
                                /*
                                 * Mark the Hyper-V TSC page feature as disabled
                                 * in a TDX VM without paravisor so that the
                                 * Invariant TSC, which is a better clocksource
                                 * anyway, is used instead.
                                 */
                                ms_hyperv.features &= ~HV_MSR_REFERENCE_TSC_AVAILABLE;

                                /*
                                 * The Invariant TSC is expected to be available
                                 * in a TDX VM without paravisor, but if not,
                                 * print a warning message. The slower Hyper-V MSR-based
                                 * Ref Counter should end up being the clocksource.
                                 */
                                if (!(ms_hyperv.features & HV_ACCESS_TSC_INVARIANT))
                                        pr_warn("Hyper-V: Invariant TSC is unavailable\n");

                                /* HV_MSR_CRASH_CTL is unsupported. */
                                ms_hyperv.misc_features &= ~HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE;

                                /* Don't trust Hyper-V's TLB-flushing hypercalls. */
                                ms_hyperv.hints &= ~HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED;

                                x86_init.acpi.reduced_hw_early_init = reduced_hw_init;
                        }
                }
        }

        if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {
                ms_hyperv.nested_features =
                        cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
                pr_info("Hyper-V: Nested features: 0x%x\n",
                        ms_hyperv.nested_features);
        }

#ifdef CONFIG_X86_LOCAL_APIC
        if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
            ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
                /*
                 * Get the APIC frequency.
                 */
                u64     hv_lapic_frequency;

                rdmsrq(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
                hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
                lapic_timer_period = hv_lapic_frequency;
                pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
                        lapic_timer_period);
        }

        register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
                             "hv_nmi_unknown");
#endif

#ifdef CONFIG_X86_IO_APIC
        no_timer_check = 1;
#endif

#if IS_ENABLED(CONFIG_HYPERV)
        if (hv_root_partition())
                machine_ops.power_off = hv_machine_power_off;
#if defined(CONFIG_KEXEC_CORE)
        machine_ops.shutdown = hv_machine_shutdown;
#endif
#if defined(CONFIG_CRASH_DUMP)
        if (!hv_root_partition())
                machine_ops.crash_shutdown = hv_guest_crash_shutdown;
#endif
#endif
        /*
         * HV_ACCESS_TSC_INVARIANT is always zero for the root partition. Root
         * partition doesn't need to write to synthetic MSR to enable invariant
         * TSC feature. It sees what the hardware provides.
         */
        if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) {
                /*
                 * Writing to synthetic MSR 0x40000118 updates/changes the
                 * guest visible CPUIDs. Setting bit 0 of this MSR  enables
                 * guests to report invariant TSC feature through CPUID
                 * instruction, CPUID 0x800000007/EDX, bit 8. See code in
                 * early_init_intel() where this bit is examined. The
                 * setting of this MSR bit should happen before init_intel()
                 * is called.
                 */
                wrmsrq(HV_X64_MSR_TSC_INVARIANT_CONTROL, HV_EXPOSE_INVARIANT_TSC);
                setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
        }

        /*
         * Generation 2 instances don't support reading the NMI status from
         * 0x61 port.
         */
        if (efi_enabled(EFI_BOOT))
                x86_platform.get_nmi_reason = hv_get_nmi_reason;

#if IS_ENABLED(CONFIG_HYPERV)
        if ((hv_get_isolation_type() == HV_ISOLATION_TYPE_VBS) ||
            ms_hyperv.paravisor_present)
                hv_vtom_init();
        /*
         * Setup the hook to get control post apic initialization.
         */
        x86_platform.apic_post_init = hyperv_init;
        hyperv_setup_mmu_ops();

        /* Install system interrupt handler for hypervisor callback */
        sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_hyperv_callback);

        /* Install system interrupt handler for reenlightenment notifications */
        if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) {
                sysvec_install(HYPERV_REENLIGHTENMENT_VECTOR, sysvec_hyperv_reenlightenment);
        }

        /* Install system interrupt handler for stimer0 */
        if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) {
                sysvec_install(HYPERV_STIMER0_VECTOR, sysvec_hyperv_stimer0);
        }

# ifdef CONFIG_SMP
        smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
        if (hv_root_partition() ||
            (!ms_hyperv.paravisor_present && hv_isolation_type_snp()))
                smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;
# endif

        /*
         * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic,
         * set x2apic destination mode to physical mode when x2apic is available
         * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs
         * have 8-bit APIC id.
         */
# ifdef CONFIG_X86_X2APIC
        if (x2apic_supported())
                x2apic_phys = 1;
# endif

        /* Register Hyper-V specific clocksource */
        hv_init_clocksource();
        x86_setup_ops_for_tsc_pg_clock();
        hv_vtl_init_platform();
#endif
        /*
         * TSC should be marked as unstable only after Hyper-V
         * clocksource has been initialized. This ensures that the
         * stability of the sched_clock is not altered.
         *
         * HV_ACCESS_TSC_INVARIANT is always zero for the root partition. No
         * need to check for it.
         */
        if (!hv_root_partition() &&
            !(ms_hyperv.features & HV_ACCESS_TSC_INVARIANT))
                mark_tsc_unstable("running on Hyper-V");

        hardlockup_detector_disable();
}

static bool __init ms_hyperv_x2apic_available(void)
{
        return x2apic_supported();
}

/*
 * If ms_hyperv_msi_ext_dest_id() returns true, hyperv_prepare_irq_remapping()
 * returns -ENODEV and the Hyper-V IOMMU driver is not used; instead, the
 * generic support of the 15-bit APIC ID is used: see __irq_msi_compose_msg().
 *
 * Note: for a VM on Hyper-V, the I/O-APIC is the only device which
 * (logically) generates MSIs directly to the system APIC irq domain.
 * There is no HPET, and PCI MSI/MSI-X interrupts are remapped by the
 * pci-hyperv host bridge.
 *
 * Note: for a Hyper-V root partition, this will always return false.
 */
static bool __init ms_hyperv_msi_ext_dest_id(void)
{
        return ms_hyperv.msi_ext_dest_id;
}

#ifdef CONFIG_AMD_MEM_ENCRYPT
static void hv_sev_es_hcall_prepare(struct ghcb *ghcb, struct pt_regs *regs)
{
        /* RAX and CPL are already in the GHCB */
        ghcb_set_rcx(ghcb, regs->cx);
        ghcb_set_rdx(ghcb, regs->dx);
        ghcb_set_r8(ghcb, regs->r8);
}

static bool hv_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
{
        /* No checking of the return state needed */
        return true;
}
#endif

const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
        .name                   = "Microsoft Hyper-V",
        .detect                 = ms_hyperv_platform,
        .type                   = X86_HYPER_MS_HYPERV,
        .init.x2apic_available  = ms_hyperv_x2apic_available,
        .init.msi_ext_dest_id   = ms_hyperv_msi_ext_dest_id,
        .init.init_platform     = ms_hyperv_init_platform,
        .init.guest_late_init   = ms_hyperv_late_init,
#ifdef CONFIG_AMD_MEM_ENCRYPT
        .runtime.sev_es_hcall_prepare = hv_sev_es_hcall_prepare,
        .runtime.sev_es_hcall_finish = hv_sev_es_hcall_finish,
#endif
};