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32 results

hyperv.c

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  • hyperv.c 54.47 KiB
    // SPDX-License-Identifier: GPL-2.0-only
    /*
     * KVM Microsoft Hyper-V emulation
     *
     * derived from arch/x86/kvm/x86.c
     *
     * Copyright (C) 2006 Qumranet, Inc.
     * Copyright (C) 2008 Qumranet, Inc.
     * Copyright IBM Corporation, 2008
     * Copyright 2010 Red Hat, Inc. and/or its affiliates.
     * Copyright (C) 2015 Andrey Smetanin <asmetanin@virtuozzo.com>
     *
     * Authors:
     *   Avi Kivity   <avi@qumranet.com>
     *   Yaniv Kamay  <yaniv@qumranet.com>
     *   Amit Shah    <amit.shah@qumranet.com>
     *   Ben-Ami Yassour <benami@il.ibm.com>
     *   Andrey Smetanin <asmetanin@virtuozzo.com>
     */
    
    #include "x86.h"
    #include "lapic.h"
    #include "ioapic.h"
    #include "cpuid.h"
    #include "hyperv.h"
    
    #include <linux/cpu.h>
    #include <linux/kvm_host.h>
    #include <linux/highmem.h>
    #include <linux/sched/cputime.h>
    #include <linux/eventfd.h>
    
    #include <asm/apicdef.h>
    #include <trace/events/kvm.h>
    
    #include "trace.h"
    #include "irq.h"
    
    #define KVM_HV_MAX_SPARSE_VCPU_SET_BITS DIV_ROUND_UP(KVM_MAX_VCPUS, 64)
    
    static void stimer_mark_pending(struct kvm_vcpu_hv_stimer *stimer,
    				bool vcpu_kick);
    
    static inline u64 synic_read_sint(struct kvm_vcpu_hv_synic *synic, int sint)
    {
    	return atomic64_read(&synic->sint[sint]);
    }
    
    static inline int synic_get_sint_vector(u64 sint_value)
    {
    	if (sint_value & HV_SYNIC_SINT_MASKED)
    		return -1;
    	return sint_value & HV_SYNIC_SINT_VECTOR_MASK;
    }
    
    static bool synic_has_vector_connected(struct kvm_vcpu_hv_synic *synic,
    				      int vector)
    {
    	int i;
    
    	for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
    		if (synic_get_sint_vector(synic_read_sint(synic, i)) == vector)
    			return true;
    	}
    	return false;
    }
    
    static bool synic_has_vector_auto_eoi(struct kvm_vcpu_hv_synic *synic,
    				     int vector)
    {
    	int i;
    	u64 sint_value;
    
    	for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
    		sint_value = synic_read_sint(synic, i);
    		if (synic_get_sint_vector(sint_value) == vector &&
    		    sint_value & HV_SYNIC_SINT_AUTO_EOI)
    			return true;
    	}
    	return false;
    }
    
    static void synic_update_vector(struct kvm_vcpu_hv_synic *synic,
    				int vector)
    {
    	if (vector < HV_SYNIC_FIRST_VALID_VECTOR)
    		return;
    
    	if (synic_has_vector_connected(synic, vector))
    		__set_bit(vector, synic->vec_bitmap);
    	else
    		__clear_bit(vector, synic->vec_bitmap);
    
    	if (synic_has_vector_auto_eoi(synic, vector))
    		__set_bit(vector, synic->auto_eoi_bitmap);
    	else
    		__clear_bit(vector, synic->auto_eoi_bitmap);
    }
    
    static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint,
    			  u64 data, bool host)
    {
    	int vector, old_vector;
    	bool masked;
    
    	vector = data & HV_SYNIC_SINT_VECTOR_MASK;
    	masked = data & HV_SYNIC_SINT_MASKED;
    
    	/*
    	 * Valid vectors are 16-255, however, nested Hyper-V attempts to write
    	 * default '0x10000' value on boot and this should not #GP. We need to
    	 * allow zero-initing the register from host as well.
    	 */
    	if (vector < HV_SYNIC_FIRST_VALID_VECTOR && !host && !masked)
    		return 1;
    	/*
    	 * Guest may configure multiple SINTs to use the same vector, so
    	 * we maintain a bitmap of vectors handled by synic, and a
    	 * bitmap of vectors with auto-eoi behavior.  The bitmaps are
    	 * updated here, and atomically queried on fast paths.
    	 */
    	old_vector = synic_read_sint(synic, sint) & HV_SYNIC_SINT_VECTOR_MASK;
    
    	atomic64_set(&synic->sint[sint], data);
    
    	synic_update_vector(synic, old_vector);
    
    	synic_update_vector(synic, vector);
    
    	/* Load SynIC vectors into EOI exit bitmap */
    	kvm_make_request(KVM_REQ_SCAN_IOAPIC, synic_to_vcpu(synic));
    	return 0;
    }
    
    static struct kvm_vcpu *get_vcpu_by_vpidx(struct kvm *kvm, u32 vpidx)
    {
    	struct kvm_vcpu *vcpu = NULL;
    	int i;
    
    	if (vpidx >= KVM_MAX_VCPUS)
    		return NULL;
    
    	vcpu = kvm_get_vcpu(kvm, vpidx);
    	if (vcpu && vcpu_to_hv_vcpu(vcpu)->vp_index == vpidx)
    		return vcpu;
    	kvm_for_each_vcpu(i, vcpu, kvm)
    		if (vcpu_to_hv_vcpu(vcpu)->vp_index == vpidx)
    			return vcpu;
    	return NULL;
    }
    
    static struct kvm_vcpu_hv_synic *synic_get(struct kvm *kvm, u32 vpidx)
    {
    	struct kvm_vcpu *vcpu;
    	struct kvm_vcpu_hv_synic *synic;
    
    	vcpu = get_vcpu_by_vpidx(kvm, vpidx);
    	if (!vcpu)
    		return NULL;
    	synic = vcpu_to_synic(vcpu);
    	return (synic->active) ? synic : NULL;
    }
    
    static void kvm_hv_notify_acked_sint(struct kvm_vcpu *vcpu, u32 sint)
    {
    	struct kvm *kvm = vcpu->kvm;
    	struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
    	struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);
    	struct kvm_vcpu_hv_stimer *stimer;
    	int gsi, idx;
    
    	trace_kvm_hv_notify_acked_sint(vcpu->vcpu_id, sint);
    
    	/* Try to deliver pending Hyper-V SynIC timers messages */
    	for (idx = 0; idx < ARRAY_SIZE(hv_vcpu->stimer); idx++) {
    		stimer = &hv_vcpu->stimer[idx];
    		if (stimer->msg_pending && stimer->config.enable &&
    		    !stimer->config.direct_mode &&
    		    stimer->config.sintx == sint)
    			stimer_mark_pending(stimer, false);
    	}
    
    	idx = srcu_read_lock(&kvm->irq_srcu);
    	gsi = atomic_read(&synic->sint_to_gsi[sint]);
    	if (gsi != -1)
    		kvm_notify_acked_gsi(kvm, gsi);
    	srcu_read_unlock(&kvm->irq_srcu, idx);
    }
    
    static void synic_exit(struct kvm_vcpu_hv_synic *synic, u32 msr)
    {
    	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
    	struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;
    
    	hv_vcpu->exit.type = KVM_EXIT_HYPERV_SYNIC;
    	hv_vcpu->exit.u.synic.msr = msr;
    	hv_vcpu->exit.u.synic.control = synic->control;
    	hv_vcpu->exit.u.synic.evt_page = synic->evt_page;
    	hv_vcpu->exit.u.synic.msg_page = synic->msg_page;
    
    	kvm_make_request(KVM_REQ_HV_EXIT, vcpu);
    }
    
    static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
    			 u32 msr, u64 data, bool host)
    {
    	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
    	int ret;
    
    	if (!synic->active && !host)
    		return 1;
    
    	trace_kvm_hv_synic_set_msr(vcpu->vcpu_id, msr, data, host);
    
    	ret = 0;
    	switch (msr) {
    	case HV_X64_MSR_SCONTROL:
    		synic->control = data;
    		if (!host)
    			synic_exit(synic, msr);
    		break;
    	case HV_X64_MSR_SVERSION:
    		if (!host) {
    			ret = 1;
    			break;
    		}
    		synic->version = data;
    		break;
    	case HV_X64_MSR_SIEFP:
    		if ((data & HV_SYNIC_SIEFP_ENABLE) && !host &&
    		    !synic->dont_zero_synic_pages)
    			if (kvm_clear_guest(vcpu->kvm,
    					    data & PAGE_MASK, PAGE_SIZE)) {
    				ret = 1;
    				break;
    			}
    		synic->evt_page = data;
    		if (!host)
    			synic_exit(synic, msr);
    		break;
    	case HV_X64_MSR_SIMP:
    		if ((data & HV_SYNIC_SIMP_ENABLE) && !host &&
    		    !synic->dont_zero_synic_pages)
    			if (kvm_clear_guest(vcpu->kvm,
    					    data & PAGE_MASK, PAGE_SIZE)) {
    				ret = 1;
    				break;
    			}
    		synic->msg_page = data;
    		if (!host)
    			synic_exit(synic, msr);
    		break;
    	case HV_X64_MSR_EOM: {
    		int i;
    
    		for (i = 0; i < ARRAY_SIZE(synic->sint); i++)
    			kvm_hv_notify_acked_sint(vcpu, i);
    		break;
    	}
    	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
    		ret = synic_set_sint(synic, msr - HV_X64_MSR_SINT0, data, host);
    		break;
    	default:
    		ret = 1;
    		break;
    	}
    	return ret;
    }
    
    static bool kvm_hv_is_syndbg_enabled(struct kvm_vcpu *vcpu)
    {
    	struct kvm_cpuid_entry2 *entry;
    
    	entry = kvm_find_cpuid_entry(vcpu,
    				     HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES,
    				     0);
    	if (!entry)
    		return false;
    
    	return entry->eax & HV_X64_SYNDBG_CAP_ALLOW_KERNEL_DEBUGGING;
    }
    
    static int kvm_hv_syndbg_complete_userspace(struct kvm_vcpu *vcpu)
    {
    	struct kvm *kvm = vcpu->kvm;
    	struct kvm_hv *hv = &kvm->arch.hyperv;
    
    	if (vcpu->run->hyperv.u.syndbg.msr == HV_X64_MSR_SYNDBG_CONTROL)
    		hv->hv_syndbg.control.status =
    			vcpu->run->hyperv.u.syndbg.status;
    	return 1;
    }
    
    static void syndbg_exit(struct kvm_vcpu *vcpu, u32 msr)
    {
    	struct kvm_hv_syndbg *syndbg = vcpu_to_hv_syndbg(vcpu);
    	struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;
    
    	hv_vcpu->exit.type = KVM_EXIT_HYPERV_SYNDBG;
    	hv_vcpu->exit.u.syndbg.msr = msr;
    	hv_vcpu->exit.u.syndbg.control = syndbg->control.control;
    	hv_vcpu->exit.u.syndbg.send_page = syndbg->control.send_page;
    	hv_vcpu->exit.u.syndbg.recv_page = syndbg->control.recv_page;
    	hv_vcpu->exit.u.syndbg.pending_page = syndbg->control.pending_page;
    	vcpu->arch.complete_userspace_io =
    			kvm_hv_syndbg_complete_userspace;
    
    	kvm_make_request(KVM_REQ_HV_EXIT, vcpu);
    }
    
    static int syndbg_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
    {
    	struct kvm_hv_syndbg *syndbg = vcpu_to_hv_syndbg(vcpu);
    
    	if (!kvm_hv_is_syndbg_enabled(vcpu) && !host)
    		return 1;
    
    	trace_kvm_hv_syndbg_set_msr(vcpu->vcpu_id,
    				    vcpu_to_hv_vcpu(vcpu)->vp_index, msr, data);
    	switch (msr) {
    	case HV_X64_MSR_SYNDBG_CONTROL:
    		syndbg->control.control = data;
    		if (!host)
    			syndbg_exit(vcpu, msr);
    		break;
    	case HV_X64_MSR_SYNDBG_STATUS:
    		syndbg->control.status = data;
    		break;
    	case HV_X64_MSR_SYNDBG_SEND_BUFFER:
    		syndbg->control.send_page = data;
    		break;
    	case HV_X64_MSR_SYNDBG_RECV_BUFFER:
    		syndbg->control.recv_page = data;
    		break;
    	case HV_X64_MSR_SYNDBG_PENDING_BUFFER:
    		syndbg->control.pending_page = data;
    		if (!host)
    			syndbg_exit(vcpu, msr);
    		break;
    	case HV_X64_MSR_SYNDBG_OPTIONS:
    		syndbg->options = data;
    		break;
    	default:
    		break;
    	}
    
    	return 0;
    }
    
    static int syndbg_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host)
    {
    	struct kvm_hv_syndbg *syndbg = vcpu_to_hv_syndbg(vcpu);
    
    	if (!kvm_hv_is_syndbg_enabled(vcpu) && !host)
    		return 1;
    
    	switch (msr) {
    	case HV_X64_MSR_SYNDBG_CONTROL:
    		*pdata = syndbg->control.control;
    		break;
    	case HV_X64_MSR_SYNDBG_STATUS:
    		*pdata = syndbg->control.status;
    		break;
    	case HV_X64_MSR_SYNDBG_SEND_BUFFER:
    		*pdata = syndbg->control.send_page;
    		break;
    	case HV_X64_MSR_SYNDBG_RECV_BUFFER:
    		*pdata = syndbg->control.recv_page;
    		break;
    	case HV_X64_MSR_SYNDBG_PENDING_BUFFER:
    		*pdata = syndbg->control.pending_page;
    		break;
    	case HV_X64_MSR_SYNDBG_OPTIONS:
    		*pdata = syndbg->options;
    		break;
    	default:
    		break;
    	}
    
    	trace_kvm_hv_syndbg_get_msr(vcpu->vcpu_id,
    				    vcpu_to_hv_vcpu(vcpu)->vp_index, msr,
    				    *pdata);
    
    	return 0;
    }
    
    static int synic_get_msr(struct kvm_vcpu_hv_synic *synic, u32 msr, u64 *pdata,
    			 bool host)
    {
    	int ret;
    
    	if (!synic->active && !host)
    		return 1;
    
    	ret = 0;
    	switch (msr) {
    	case HV_X64_MSR_SCONTROL:
    		*pdata = synic->control;
    		break;
    	case HV_X64_MSR_SVERSION:
    		*pdata = synic->version;
    		break;
    	case HV_X64_MSR_SIEFP:
    		*pdata = synic->evt_page;
    		break;
    	case HV_X64_MSR_SIMP:
    		*pdata = synic->msg_page;
    		break;
    	case HV_X64_MSR_EOM:
    		*pdata = 0;
    		break;
    	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
    		*pdata = atomic64_read(&synic->sint[msr - HV_X64_MSR_SINT0]);
    		break;
    	default:
    		ret = 1;
    		break;
    	}
    	return ret;
    }
    
    static int synic_set_irq(struct kvm_vcpu_hv_synic *synic, u32 sint)
    {
    	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
    	struct kvm_lapic_irq irq;
    	int ret, vector;
    
    	if (sint >= ARRAY_SIZE(synic->sint))
    		return -EINVAL;
    
    	vector = synic_get_sint_vector(synic_read_sint(synic, sint));
    	if (vector < 0)
    		return -ENOENT;
    
    	memset(&irq, 0, sizeof(irq));
    	irq.shorthand = APIC_DEST_SELF;
    	irq.dest_mode = APIC_DEST_PHYSICAL;
    	irq.delivery_mode = APIC_DM_FIXED;
    	irq.vector = vector;
    	irq.level = 1;
    
    	ret = kvm_irq_delivery_to_apic(vcpu->kvm, vcpu->arch.apic, &irq, NULL);
    	trace_kvm_hv_synic_set_irq(vcpu->vcpu_id, sint, irq.vector, ret);
    	return ret;
    }
    
    int kvm_hv_synic_set_irq(struct kvm *kvm, u32 vpidx, u32 sint)
    {
    	struct kvm_vcpu_hv_synic *synic;
    
    	synic = synic_get(kvm, vpidx);
    	if (!synic)
    		return -EINVAL;
    
    	return synic_set_irq(synic, sint);
    }
    
    void kvm_hv_synic_send_eoi(struct kvm_vcpu *vcpu, int vector)
    {
    	struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
    	int i;
    
    	trace_kvm_hv_synic_send_eoi(vcpu->vcpu_id, vector);
    
    	for (i = 0; i < ARRAY_SIZE(synic->sint); i++)
    		if (synic_get_sint_vector(synic_read_sint(synic, i)) == vector)
    			kvm_hv_notify_acked_sint(vcpu, i);
    }
    
    static int kvm_hv_set_sint_gsi(struct kvm *kvm, u32 vpidx, u32 sint, int gsi)
    {
    	struct kvm_vcpu_hv_synic *synic;
    
    	synic = synic_get(kvm, vpidx);
    	if (!synic)
    		return -EINVAL;
    
    	if (sint >= ARRAY_SIZE(synic->sint_to_gsi))
    		return -EINVAL;
    
    	atomic_set(&synic->sint_to_gsi[sint], gsi);
    	return 0;
    }
    
    void kvm_hv_irq_routing_update(struct kvm *kvm)
    {
    	struct kvm_irq_routing_table *irq_rt;
    	struct kvm_kernel_irq_routing_entry *e;
    	u32 gsi;
    
    	irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu,
    					lockdep_is_held(&kvm->irq_lock));
    
    	for (gsi = 0; gsi < irq_rt->nr_rt_entries; gsi++) {
    		hlist_for_each_entry(e, &irq_rt->map[gsi], link) {
    			if (e->type == KVM_IRQ_ROUTING_HV_SINT)
    				kvm_hv_set_sint_gsi(kvm, e->hv_sint.vcpu,
    						    e->hv_sint.sint, gsi);
    		}
    	}
    }
    
    static void synic_init(struct kvm_vcpu_hv_synic *synic)
    {
    	int i;
    
    	memset(synic, 0, sizeof(*synic));
    	synic->version = HV_SYNIC_VERSION_1;
    	for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
    		atomic64_set(&synic->sint[i], HV_SYNIC_SINT_MASKED);
    		atomic_set(&synic->sint_to_gsi[i], -1);
    	}
    }
    
    static u64 get_time_ref_counter(struct kvm *kvm)
    {
    	struct kvm_hv *hv = &kvm->arch.hyperv;
    	struct kvm_vcpu *vcpu;
    	u64 tsc;
    
    	/*
    	 * The guest has not set up the TSC page or the clock isn't
    	 * stable, fall back to get_kvmclock_ns.
    	 */
    	if (!hv->tsc_ref.tsc_sequence)
    		return div_u64(get_kvmclock_ns(kvm), 100);
    
    	vcpu = kvm_get_vcpu(kvm, 0);
    	tsc = kvm_read_l1_tsc(vcpu, rdtsc());
    	return mul_u64_u64_shr(tsc, hv->tsc_ref.tsc_scale, 64)
    		+ hv->tsc_ref.tsc_offset;
    }
    
    static void stimer_mark_pending(struct kvm_vcpu_hv_stimer *stimer,
    				bool vcpu_kick)
    {
    	struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer);
    
    	set_bit(stimer->index,
    		vcpu_to_hv_vcpu(vcpu)->stimer_pending_bitmap);
    	kvm_make_request(KVM_REQ_HV_STIMER, vcpu);
    	if (vcpu_kick)
    		kvm_vcpu_kick(vcpu);
    }
    
    static void stimer_cleanup(struct kvm_vcpu_hv_stimer *stimer)
    {
    	struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer);
    
    	trace_kvm_hv_stimer_cleanup(stimer_to_vcpu(stimer)->vcpu_id,
    				    stimer->index);
    
    	hrtimer_cancel(&stimer->timer);
    	clear_bit(stimer->index,
    		  vcpu_to_hv_vcpu(vcpu)->stimer_pending_bitmap);
    	stimer->msg_pending = false;
    	stimer->exp_time = 0;
    }
    
    static enum hrtimer_restart stimer_timer_callback(struct hrtimer *timer)
    {
    	struct kvm_vcpu_hv_stimer *stimer;
    
    	stimer = container_of(timer, struct kvm_vcpu_hv_stimer, timer);
    	trace_kvm_hv_stimer_callback(stimer_to_vcpu(stimer)->vcpu_id,
    				     stimer->index);
    	stimer_mark_pending(stimer, true);
    
    	return HRTIMER_NORESTART;
    }
    
    /*
     * stimer_start() assumptions:
     * a) stimer->count is not equal to 0
     * b) stimer->config has HV_STIMER_ENABLE flag
     */
    static int stimer_start(struct kvm_vcpu_hv_stimer *stimer)
    {
    	u64 time_now;
    	ktime_t ktime_now;
    
    	time_now = get_time_ref_counter(stimer_to_vcpu(stimer)->kvm);
    	ktime_now = ktime_get();
    
    	if (stimer->config.periodic) {
    		if (stimer->exp_time) {
    			if (time_now >= stimer->exp_time) {
    				u64 remainder;
    
    				div64_u64_rem(time_now - stimer->exp_time,
    					      stimer->count, &remainder);
    				stimer->exp_time =
    					time_now + (stimer->count - remainder);
    			}
    		} else
    			stimer->exp_time = time_now + stimer->count;
    
    		trace_kvm_hv_stimer_start_periodic(
    					stimer_to_vcpu(stimer)->vcpu_id,
    					stimer->index,
    					time_now, stimer->exp_time);
    
    		hrtimer_start(&stimer->timer,
    			      ktime_add_ns(ktime_now,
    					   100 * (stimer->exp_time - time_now)),
    			      HRTIMER_MODE_ABS);
    		return 0;
    	}
    	stimer->exp_time = stimer->count;
    	if (time_now >= stimer->count) {
    		/*
    		 * Expire timer according to Hypervisor Top-Level Functional
    		 * specification v4(15.3.1):
    		 * "If a one shot is enabled and the specified count is in
    		 * the past, it will expire immediately."
    		 */
    		stimer_mark_pending(stimer, false);
    		return 0;
    	}
    
    	trace_kvm_hv_stimer_start_one_shot(stimer_to_vcpu(stimer)->vcpu_id,
    					   stimer->index,
    					   time_now, stimer->count);
    
    	hrtimer_start(&stimer->timer,
    		      ktime_add_ns(ktime_now, 100 * (stimer->count - time_now)),
    		      HRTIMER_MODE_ABS);
    	return 0;
    }
    
    static int stimer_set_config(struct kvm_vcpu_hv_stimer *stimer, u64 config,
    			     bool host)
    {
    	union hv_stimer_config new_config = {.as_uint64 = config},
    		old_config = {.as_uint64 = stimer->config.as_uint64};
    
    	trace_kvm_hv_stimer_set_config(stimer_to_vcpu(stimer)->vcpu_id,
    				       stimer->index, config, host);
    
    	stimer_cleanup(stimer);
    	if (old_config.enable &&
    	    !new_config.direct_mode && new_config.sintx == 0)
    		new_config.enable = 0;
    	stimer->config.as_uint64 = new_config.as_uint64;
    
    	if (stimer->config.enable)
    		stimer_mark_pending(stimer, false);
    
    	return 0;
    }
    
    static int stimer_set_count(struct kvm_vcpu_hv_stimer *stimer, u64 count,
    			    bool host)
    {
    	trace_kvm_hv_stimer_set_count(stimer_to_vcpu(stimer)->vcpu_id,
    				      stimer->index, count, host);
    
    	stimer_cleanup(stimer);
    	stimer->count = count;
    	if (stimer->count == 0)
    		stimer->config.enable = 0;
    	else if (stimer->config.auto_enable)
    		stimer->config.enable = 1;
    
    	if (stimer->config.enable)
    		stimer_mark_pending(stimer, false);
    
    	return 0;
    }
    
    static int stimer_get_config(struct kvm_vcpu_hv_stimer *stimer, u64 *pconfig)
    {
    	*pconfig = stimer->config.as_uint64;
    	return 0;
    }
    
    static int stimer_get_count(struct kvm_vcpu_hv_stimer *stimer, u64 *pcount)
    {
    	*pcount = stimer->count;
    	return 0;
    }
    
    static int synic_deliver_msg(struct kvm_vcpu_hv_synic *synic, u32 sint,
    			     struct hv_message *src_msg, bool no_retry)
    {
    	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
    	int msg_off = offsetof(struct hv_message_page, sint_message[sint]);
    	gfn_t msg_page_gfn;
    	struct hv_message_header hv_hdr;
    	int r;
    
    	if (!(synic->msg_page & HV_SYNIC_SIMP_ENABLE))
    		return -ENOENT;
    
    	msg_page_gfn = synic->msg_page >> PAGE_SHIFT;
    
    	/*
    	 * Strictly following the spec-mandated ordering would assume setting
    	 * .msg_pending before checking .message_type.  However, this function
    	 * is only called in vcpu context so the entire update is atomic from
    	 * guest POV and thus the exact order here doesn't matter.
    	 */
    	r = kvm_vcpu_read_guest_page(vcpu, msg_page_gfn, &hv_hdr.message_type,
    				     msg_off + offsetof(struct hv_message,
    							header.message_type),
    				     sizeof(hv_hdr.message_type));
    	if (r < 0)
    		return r;
    
    	if (hv_hdr.message_type != HVMSG_NONE) {
    		if (no_retry)
    			return 0;
    
    		hv_hdr.message_flags.msg_pending = 1;
    		r = kvm_vcpu_write_guest_page(vcpu, msg_page_gfn,
    					      &hv_hdr.message_flags,
    					      msg_off +
    					      offsetof(struct hv_message,
    						       header.message_flags),
    					      sizeof(hv_hdr.message_flags));
    		if (r < 0)
    			return r;
    		return -EAGAIN;
    	}
    
    	r = kvm_vcpu_write_guest_page(vcpu, msg_page_gfn, src_msg, msg_off,
    				      sizeof(src_msg->header) +
    				      src_msg->header.payload_size);
    	if (r < 0)
    		return r;
    
    	r = synic_set_irq(synic, sint);
    	if (r < 0)
    		return r;
    	if (r == 0)
    		return -EFAULT;
    	return 0;
    }
    
    static int stimer_send_msg(struct kvm_vcpu_hv_stimer *stimer)
    {
    	struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer);
    	struct hv_message *msg = &stimer->msg;
    	struct hv_timer_message_payload *payload =
    			(struct hv_timer_message_payload *)&msg->u.payload;
    
    	/*
    	 * To avoid piling up periodic ticks, don't retry message
    	 * delivery for them (within "lazy" lost ticks policy).
    	 */
    	bool no_retry = stimer->config.periodic;
    
    	payload->expiration_time = stimer->exp_time;
    	payload->delivery_time = get_time_ref_counter(vcpu->kvm);
    	return synic_deliver_msg(vcpu_to_synic(vcpu),
    				 stimer->config.sintx, msg,
    				 no_retry);
    }
    
    static int stimer_notify_direct(struct kvm_vcpu_hv_stimer *stimer)
    {
    	struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer);
    	struct kvm_lapic_irq irq = {
    		.delivery_mode = APIC_DM_FIXED,
    		.vector = stimer->config.apic_vector
    	};
    
    	if (lapic_in_kernel(vcpu))
    		return !kvm_apic_set_irq(vcpu, &irq, NULL);
    	return 0;
    }
    
    static void stimer_expiration(struct kvm_vcpu_hv_stimer *stimer)
    {
    	int r, direct = stimer->config.direct_mode;
    
    	stimer->msg_pending = true;
    	if (!direct)
    		r = stimer_send_msg(stimer);
    	else
    		r = stimer_notify_direct(stimer);
    	trace_kvm_hv_stimer_expiration(stimer_to_vcpu(stimer)->vcpu_id,
    				       stimer->index, direct, r);
    	if (!r) {
    		stimer->msg_pending = false;
    		if (!(stimer->config.periodic))
    			stimer->config.enable = 0;
    	}
    }
    
    void kvm_hv_process_stimers(struct kvm_vcpu *vcpu)
    {
    	struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);
    	struct kvm_vcpu_hv_stimer *stimer;
    	u64 time_now, exp_time;
    	int i;
    
    	for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)
    		if (test_and_clear_bit(i, hv_vcpu->stimer_pending_bitmap)) {
    			stimer = &hv_vcpu->stimer[i];
    			if (stimer->config.enable) {
    				exp_time = stimer->exp_time;
    
    				if (exp_time) {
    					time_now =
    						get_time_ref_counter(vcpu->kvm);
    					if (time_now >= exp_time)
    						stimer_expiration(stimer);
    				}
    
    				if ((stimer->config.enable) &&
    				    stimer->count) {
    					if (!stimer->msg_pending)
    						stimer_start(stimer);
    				} else
    					stimer_cleanup(stimer);
    			}
    		}
    }
    
    void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu)
    {
    	struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);
    	int i;
    
    	for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)
    		stimer_cleanup(&hv_vcpu->stimer[i]);
    }
    
    bool kvm_hv_assist_page_enabled(struct kvm_vcpu *vcpu)
    {
    	if (!(vcpu->arch.hyperv.hv_vapic & HV_X64_MSR_VP_ASSIST_PAGE_ENABLE))
    		return false;
    	return vcpu->arch.pv_eoi.msr_val & KVM_MSR_ENABLED;
    }
    EXPORT_SYMBOL_GPL(kvm_hv_assist_page_enabled);
    
    bool kvm_hv_get_assist_page(struct kvm_vcpu *vcpu,
    			    struct hv_vp_assist_page *assist_page)
    {
    	if (!kvm_hv_assist_page_enabled(vcpu))
    		return false;
    	return !kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.pv_eoi.data,
    				      assist_page, sizeof(*assist_page));
    }
    EXPORT_SYMBOL_GPL(kvm_hv_get_assist_page);
    
    static void stimer_prepare_msg(struct kvm_vcpu_hv_stimer *stimer)
    {
    	struct hv_message *msg = &stimer->msg;
    	struct hv_timer_message_payload *payload =
    			(struct hv_timer_message_payload *)&msg->u.payload;
    
    	memset(&msg->header, 0, sizeof(msg->header));
    	msg->header.message_type = HVMSG_TIMER_EXPIRED;
    	msg->header.payload_size = sizeof(*payload);
    
    	payload->timer_index = stimer->index;
    	payload->expiration_time = 0;
    	payload->delivery_time = 0;
    }
    
    static void stimer_init(struct kvm_vcpu_hv_stimer *stimer, int timer_index)
    {
    	memset(stimer, 0, sizeof(*stimer));
    	stimer->index = timer_index;
    	hrtimer_init(&stimer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
    	stimer->timer.function = stimer_timer_callback;
    	stimer_prepare_msg(stimer);
    }
    
    void kvm_hv_vcpu_init(struct kvm_vcpu *vcpu)
    {
    	struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);
    	int i;
    
    	synic_init(&hv_vcpu->synic);
    
    	bitmap_zero(hv_vcpu->stimer_pending_bitmap, HV_SYNIC_STIMER_COUNT);
    	for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)
    		stimer_init(&hv_vcpu->stimer[i], i);
    }
    
    void kvm_hv_vcpu_postcreate(struct kvm_vcpu *vcpu)
    {
    	struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);
    
    	hv_vcpu->vp_index = kvm_vcpu_get_idx(vcpu);
    }
    
    int kvm_hv_activate_synic(struct kvm_vcpu *vcpu, bool dont_zero_synic_pages)
    {
    	struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
    
    	/*
    	 * Hyper-V SynIC auto EOI SINT's are
    	 * not compatible with APICV, so request
    	 * to deactivate APICV permanently.
    	 */
    	kvm_request_apicv_update(vcpu->kvm, false, APICV_INHIBIT_REASON_HYPERV);
    	synic->active = true;
    	synic->dont_zero_synic_pages = dont_zero_synic_pages;
    	synic->control = HV_SYNIC_CONTROL_ENABLE;
    	return 0;
    }
    
    static bool kvm_hv_msr_partition_wide(u32 msr)
    {
    	bool r = false;
    
    	switch (msr) {
    	case HV_X64_MSR_GUEST_OS_ID:
    	case HV_X64_MSR_HYPERCALL:
    	case HV_X64_MSR_REFERENCE_TSC:
    	case HV_X64_MSR_TIME_REF_COUNT:
    	case HV_X64_MSR_CRASH_CTL:
    	case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
    	case HV_X64_MSR_RESET:
    	case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
    	case HV_X64_MSR_TSC_EMULATION_CONTROL:
    	case HV_X64_MSR_TSC_EMULATION_STATUS:
    	case HV_X64_MSR_SYNDBG_OPTIONS:
    	case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
    		r = true;
    		break;
    	}
    
    	return r;
    }
    
    static int kvm_hv_msr_get_crash_data(struct kvm_vcpu *vcpu,
    				     u32 index, u64 *pdata)
    {
    	struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;
    	size_t size = ARRAY_SIZE(hv->hv_crash_param);
    
    	if (WARN_ON_ONCE(index >= size))
    		return -EINVAL;
    
    	*pdata = hv->hv_crash_param[array_index_nospec(index, size)];
    	return 0;
    }
    
    static int kvm_hv_msr_get_crash_ctl(struct kvm_vcpu *vcpu, u64 *pdata)
    {
    	struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;
    
    	*pdata = hv->hv_crash_ctl;
    	return 0;
    }
    
    static int kvm_hv_msr_set_crash_ctl(struct kvm_vcpu *vcpu, u64 data, bool host)
    {
    	struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;
    
    	if (host)
    		hv->hv_crash_ctl = data & HV_CRASH_CTL_CRASH_NOTIFY;
    
    	if (!host && (data & HV_CRASH_CTL_CRASH_NOTIFY)) {
    
    		vcpu_debug(vcpu, "hv crash (0x%llx 0x%llx 0x%llx 0x%llx 0x%llx)\n",
    			  hv->hv_crash_param[0],
    			  hv->hv_crash_param[1],
    			  hv->hv_crash_param[2],
    			  hv->hv_crash_param[3],
    			  hv->hv_crash_param[4]);
    
    		/* Send notification about crash to user space */
    		kvm_make_request(KVM_REQ_HV_CRASH, vcpu);
    	}
    
    	return 0;
    }
    
    static int kvm_hv_msr_set_crash_data(struct kvm_vcpu *vcpu,
    				     u32 index, u64 data)
    {
    	struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;
    	size_t size = ARRAY_SIZE(hv->hv_crash_param);
    
    	if (WARN_ON_ONCE(index >= size))
    		return -EINVAL;
    
    	hv->hv_crash_param[array_index_nospec(index, size)] = data;
    	return 0;
    }
    
    /*
     * The kvmclock and Hyper-V TSC page use similar formulas, and converting
     * between them is possible:
     *
     * kvmclock formula:
     *    nsec = (ticks - tsc_timestamp) * tsc_to_system_mul * 2^(tsc_shift-32)
     *           + system_time
     *
     * Hyper-V formula:
     *    nsec/100 = ticks * scale / 2^64 + offset
     *
     * When tsc_timestamp = system_time = 0, offset is zero in the Hyper-V formula.
     * By dividing the kvmclock formula by 100 and equating what's left we get:
     *    ticks * scale / 2^64 = ticks * tsc_to_system_mul * 2^(tsc_shift-32) / 100
     *            scale / 2^64 =         tsc_to_system_mul * 2^(tsc_shift-32) / 100
     *            scale        =         tsc_to_system_mul * 2^(32+tsc_shift) / 100
     *
     * Now expand the kvmclock formula and divide by 100:
     *    nsec = ticks * tsc_to_system_mul * 2^(tsc_shift-32)
     *           - tsc_timestamp * tsc_to_system_mul * 2^(tsc_shift-32)
     *           + system_time
     *    nsec/100 = ticks * tsc_to_system_mul * 2^(tsc_shift-32) / 100
     *               - tsc_timestamp * tsc_to_system_mul * 2^(tsc_shift-32) / 100
     *               + system_time / 100
     *
     * Replace tsc_to_system_mul * 2^(tsc_shift-32) / 100 by scale / 2^64:
     *    nsec/100 = ticks * scale / 2^64
     *               - tsc_timestamp * scale / 2^64
     *               + system_time / 100
     *
     * Equate with the Hyper-V formula so that ticks * scale / 2^64 cancels out:
     *    offset = system_time / 100 - tsc_timestamp * scale / 2^64
     *
     * These two equivalencies are implemented in this function.
     */
    static bool compute_tsc_page_parameters(struct pvclock_vcpu_time_info *hv_clock,
    					struct ms_hyperv_tsc_page *tsc_ref)
    {
    	u64 max_mul;
    
    	if (!(hv_clock->flags & PVCLOCK_TSC_STABLE_BIT))
    		return false;
    
    	/*
    	 * check if scale would overflow, if so we use the time ref counter
    	 *    tsc_to_system_mul * 2^(tsc_shift+32) / 100 >= 2^64
    	 *    tsc_to_system_mul / 100 >= 2^(32-tsc_shift)
    	 *    tsc_to_system_mul >= 100 * 2^(32-tsc_shift)
    	 */
    	max_mul = 100ull << (32 - hv_clock->tsc_shift);
    	if (hv_clock->tsc_to_system_mul >= max_mul)
    		return false;
    
    	/*
    	 * Otherwise compute the scale and offset according to the formulas
    	 * derived above.
    	 */
    	tsc_ref->tsc_scale =
    		mul_u64_u32_div(1ULL << (32 + hv_clock->tsc_shift),
    				hv_clock->tsc_to_system_mul,
    				100);
    
    	tsc_ref->tsc_offset = hv_clock->system_time;
    	do_div(tsc_ref->tsc_offset, 100);
    	tsc_ref->tsc_offset -=
    		mul_u64_u64_shr(hv_clock->tsc_timestamp, tsc_ref->tsc_scale, 64);
    	return true;
    }
    
    void kvm_hv_setup_tsc_page(struct kvm *kvm,
    			   struct pvclock_vcpu_time_info *hv_clock)
    {
    	struct kvm_hv *hv = &kvm->arch.hyperv;
    	u32 tsc_seq;
    	u64 gfn;
    
    	BUILD_BUG_ON(sizeof(tsc_seq) != sizeof(hv->tsc_ref.tsc_sequence));
    	BUILD_BUG_ON(offsetof(struct ms_hyperv_tsc_page, tsc_sequence) != 0);
    
    	if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE))
    		return;
    
    	mutex_lock(&kvm->arch.hyperv.hv_lock);
    	if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE))
    		goto out_unlock;
    
    	gfn = hv->hv_tsc_page >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
    	/*
    	 * Because the TSC parameters only vary when there is a
    	 * change in the master clock, do not bother with caching.
    	 */
    	if (unlikely(kvm_read_guest(kvm, gfn_to_gpa(gfn),
    				    &tsc_seq, sizeof(tsc_seq))))
    		goto out_unlock;
    
    	/*
    	 * While we're computing and writing the parameters, force the
    	 * guest to use the time reference count MSR.
    	 */
    	hv->tsc_ref.tsc_sequence = 0;
    	if (kvm_write_guest(kvm, gfn_to_gpa(gfn),
    			    &hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence)))
    		goto out_unlock;
    
    	if (!compute_tsc_page_parameters(hv_clock, &hv->tsc_ref))
    		goto out_unlock;
    
    	/* Ensure sequence is zero before writing the rest of the struct.  */
    	smp_wmb();
    	if (kvm_write_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref)))
    		goto out_unlock;
    
    	/*
    	 * Now switch to the TSC page mechanism by writing the sequence.
    	 */
    	tsc_seq++;
    	if (tsc_seq == 0xFFFFFFFF || tsc_seq == 0)
    		tsc_seq = 1;
    
    	/* Write the struct entirely before the non-zero sequence.  */
    	smp_wmb();
    
    	hv->tsc_ref.tsc_sequence = tsc_seq;
    	kvm_write_guest(kvm, gfn_to_gpa(gfn),
    			&hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence));
    out_unlock:
    	mutex_unlock(&kvm->arch.hyperv.hv_lock);
    }
    
    static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data,
    			     bool host)
    {
    	struct kvm *kvm = vcpu->kvm;
    	struct kvm_hv *hv = &kvm->arch.hyperv;
    
    	switch (msr) {
    	case HV_X64_MSR_GUEST_OS_ID:
    		hv->hv_guest_os_id = data;
    		/* setting guest os id to zero disables hypercall page */
    		if (!hv->hv_guest_os_id)
    			hv->hv_hypercall &= ~HV_X64_MSR_HYPERCALL_ENABLE;
    		break;
    	case HV_X64_MSR_HYPERCALL: {
    		u64 gfn;
    		unsigned long addr;
    		u8 instructions[4];
    
    		/* if guest os id is not set hypercall should remain disabled */
    		if (!hv->hv_guest_os_id)
    			break;
    		if (!(data & HV_X64_MSR_HYPERCALL_ENABLE)) {
    			hv->hv_hypercall = data;
    			break;
    		}
    		gfn = data >> HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT;
    		addr = gfn_to_hva(kvm, gfn);
    		if (kvm_is_error_hva(addr))
    			return 1;
    		kvm_x86_ops.patch_hypercall(vcpu, instructions);
    		((unsigned char *)instructions)[3] = 0xc3; /* ret */
    		if (__copy_to_user((void __user *)addr, instructions, 4))
    			return 1;
    		hv->hv_hypercall = data;
    		mark_page_dirty(kvm, gfn);
    		break;
    	}
    	case HV_X64_MSR_REFERENCE_TSC:
    		hv->hv_tsc_page = data;
    		if (hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE)
    			kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
    		break;
    	case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
    		return kvm_hv_msr_set_crash_data(vcpu,
    						 msr - HV_X64_MSR_CRASH_P0,
    						 data);
    	case HV_X64_MSR_CRASH_CTL:
    		return kvm_hv_msr_set_crash_ctl(vcpu, data, host);
    	case HV_X64_MSR_RESET:
    		if (data == 1) {
    			vcpu_debug(vcpu, "hyper-v reset requested\n");
    			kvm_make_request(KVM_REQ_HV_RESET, vcpu);
    		}
    		break;
    	case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
    		hv->hv_reenlightenment_control = data;
    		break;
    	case HV_X64_MSR_TSC_EMULATION_CONTROL:
    		hv->hv_tsc_emulation_control = data;
    		break;
    	case HV_X64_MSR_TSC_EMULATION_STATUS:
    		hv->hv_tsc_emulation_status = data;
    		break;
    	case HV_X64_MSR_TIME_REF_COUNT:
    		/* read-only, but still ignore it if host-initiated */
    		if (!host)
    			return 1;
    		break;
    	case HV_X64_MSR_SYNDBG_OPTIONS:
    	case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
    		return syndbg_set_msr(vcpu, msr, data, host);
    	default:
    		vcpu_unimpl(vcpu, "Hyper-V unhandled wrmsr: 0x%x data 0x%llx\n",
    			    msr, data);
    		return 1;
    	}
    	return 0;
    }
    
    /* Calculate cpu time spent by current task in 100ns units */
    static u64 current_task_runtime_100ns(void)
    {
    	u64 utime, stime;
    
    	task_cputime_adjusted(current, &utime, &stime);
    
    	return div_u64(utime + stime, 100);
    }
    
    static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
    {
    	struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;
    
    	switch (msr) {
    	case HV_X64_MSR_VP_INDEX: {
    		struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;
    		int vcpu_idx = kvm_vcpu_get_idx(vcpu);
    		u32 new_vp_index = (u32)data;
    
    		if (!host || new_vp_index >= KVM_MAX_VCPUS)
    			return 1;
    
    		if (new_vp_index == hv_vcpu->vp_index)
    			return 0;
    
    		/*
    		 * The VP index is initialized to vcpu_index by
    		 * kvm_hv_vcpu_postcreate so they initially match.  Now the
    		 * VP index is changing, adjust num_mismatched_vp_indexes if
    		 * it now matches or no longer matches vcpu_idx.
    		 */
    		if (hv_vcpu->vp_index == vcpu_idx)
    			atomic_inc(&hv->num_mismatched_vp_indexes);
    		else if (new_vp_index == vcpu_idx)
    			atomic_dec(&hv->num_mismatched_vp_indexes);
    
    		hv_vcpu->vp_index = new_vp_index;
    		break;
    	}
    	case HV_X64_MSR_VP_ASSIST_PAGE: {
    		u64 gfn;
    		unsigned long addr;
    
    		if (!(data & HV_X64_MSR_VP_ASSIST_PAGE_ENABLE)) {
    			hv_vcpu->hv_vapic = data;
    			if (kvm_lapic_enable_pv_eoi(vcpu, 0, 0))
    				return 1;
    			break;
    		}
    		gfn = data >> HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT;
    		addr = kvm_vcpu_gfn_to_hva(vcpu, gfn);
    		if (kvm_is_error_hva(addr))
    			return 1;
    
    		/*
    		 * Clear apic_assist portion of struct hv_vp_assist_page
    		 * only, there can be valuable data in the rest which needs
    		 * to be preserved e.g. on migration.
    		 */
    		if (__put_user(0, (u32 __user *)addr))
    			return 1;
    		hv_vcpu->hv_vapic = data;
    		kvm_vcpu_mark_page_dirty(vcpu, gfn);
    		if (kvm_lapic_enable_pv_eoi(vcpu,
    					    gfn_to_gpa(gfn) | KVM_MSR_ENABLED,
    					    sizeof(struct hv_vp_assist_page)))
    			return 1;
    		break;
    	}
    	case HV_X64_MSR_EOI:
    		return kvm_hv_vapic_msr_write(vcpu, APIC_EOI, data);
    	case HV_X64_MSR_ICR:
    		return kvm_hv_vapic_msr_write(vcpu, APIC_ICR, data);
    	case HV_X64_MSR_TPR:
    		return kvm_hv_vapic_msr_write(vcpu, APIC_TASKPRI, data);
    	case HV_X64_MSR_VP_RUNTIME:
    		if (!host)
    			return 1;
    		hv_vcpu->runtime_offset = data - current_task_runtime_100ns();
    		break;
    	case HV_X64_MSR_SCONTROL:
    	case HV_X64_MSR_SVERSION:
    	case HV_X64_MSR_SIEFP:
    	case HV_X64_MSR_SIMP:
    	case HV_X64_MSR_EOM:
    	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
    		return synic_set_msr(vcpu_to_synic(vcpu), msr, data, host);
    	case HV_X64_MSR_STIMER0_CONFIG:
    	case HV_X64_MSR_STIMER1_CONFIG:
    	case HV_X64_MSR_STIMER2_CONFIG:
    	case HV_X64_MSR_STIMER3_CONFIG: {
    		int timer_index = (msr - HV_X64_MSR_STIMER0_CONFIG)/2;
    
    		return stimer_set_config(vcpu_to_stimer(vcpu, timer_index),
    					 data, host);
    	}
    	case HV_X64_MSR_STIMER0_COUNT:
    	case HV_X64_MSR_STIMER1_COUNT:
    	case HV_X64_MSR_STIMER2_COUNT:
    	case HV_X64_MSR_STIMER3_COUNT: {
    		int timer_index = (msr - HV_X64_MSR_STIMER0_COUNT)/2;
    
    		return stimer_set_count(vcpu_to_stimer(vcpu, timer_index),
    					data, host);
    	}
    	case HV_X64_MSR_TSC_FREQUENCY:
    	case HV_X64_MSR_APIC_FREQUENCY:
    		/* read-only, but still ignore it if host-initiated */
    		if (!host)
    			return 1;
    		break;
    	default:
    		vcpu_unimpl(vcpu, "Hyper-V unhandled wrmsr: 0x%x data 0x%llx\n",
    			    msr, data);
    		return 1;
    	}
    
    	return 0;
    }
    
    static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata,
    			     bool host)
    {
    	u64 data = 0;
    	struct kvm *kvm = vcpu->kvm;
    	struct kvm_hv *hv = &kvm->arch.hyperv;
    
    	switch (msr) {
    	case HV_X64_MSR_GUEST_OS_ID:
    		data = hv->hv_guest_os_id;
    		break;
    	case HV_X64_MSR_HYPERCALL:
    		data = hv->hv_hypercall;
    		break;
    	case HV_X64_MSR_TIME_REF_COUNT:
    		data = get_time_ref_counter(kvm);
    		break;
    	case HV_X64_MSR_REFERENCE_TSC:
    		data = hv->hv_tsc_page;
    		break;
    	case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
    		return kvm_hv_msr_get_crash_data(vcpu,
    						 msr - HV_X64_MSR_CRASH_P0,
    						 pdata);
    	case HV_X64_MSR_CRASH_CTL:
    		return kvm_hv_msr_get_crash_ctl(vcpu, pdata);
    	case HV_X64_MSR_RESET:
    		data = 0;
    		break;
    	case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
    		data = hv->hv_reenlightenment_control;
    		break;
    	case HV_X64_MSR_TSC_EMULATION_CONTROL:
    		data = hv->hv_tsc_emulation_control;
    		break;
    	case HV_X64_MSR_TSC_EMULATION_STATUS:
    		data = hv->hv_tsc_emulation_status;
    		break;
    	case HV_X64_MSR_SYNDBG_OPTIONS:
    	case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
    		return syndbg_get_msr(vcpu, msr, pdata, host);
    	default:
    		vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr);
    		return 1;
    	}
    
    	*pdata = data;
    	return 0;
    }
    
    static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata,
    			  bool host)
    {
    	u64 data = 0;
    	struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;
    
    	switch (msr) {
    	case HV_X64_MSR_VP_INDEX:
    		data = hv_vcpu->vp_index;
    		break;
    	case HV_X64_MSR_EOI:
    		return kvm_hv_vapic_msr_read(vcpu, APIC_EOI, pdata);
    	case HV_X64_MSR_ICR:
    		return kvm_hv_vapic_msr_read(vcpu, APIC_ICR, pdata);
    	case HV_X64_MSR_TPR:
    		return kvm_hv_vapic_msr_read(vcpu, APIC_TASKPRI, pdata);
    	case HV_X64_MSR_VP_ASSIST_PAGE:
    		data = hv_vcpu->hv_vapic;
    		break;
    	case HV_X64_MSR_VP_RUNTIME:
    		data = current_task_runtime_100ns() + hv_vcpu->runtime_offset;
    		break;
    	case HV_X64_MSR_SCONTROL:
    	case HV_X64_MSR_SVERSION:
    	case HV_X64_MSR_SIEFP:
    	case HV_X64_MSR_SIMP:
    	case HV_X64_MSR_EOM:
    	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
    		return synic_get_msr(vcpu_to_synic(vcpu), msr, pdata, host);
    	case HV_X64_MSR_STIMER0_CONFIG:
    	case HV_X64_MSR_STIMER1_CONFIG:
    	case HV_X64_MSR_STIMER2_CONFIG:
    	case HV_X64_MSR_STIMER3_CONFIG: {
    		int timer_index = (msr - HV_X64_MSR_STIMER0_CONFIG)/2;
    
    		return stimer_get_config(vcpu_to_stimer(vcpu, timer_index),
    					 pdata);
    	}
    	case HV_X64_MSR_STIMER0_COUNT:
    	case HV_X64_MSR_STIMER1_COUNT:
    	case HV_X64_MSR_STIMER2_COUNT:
    	case HV_X64_MSR_STIMER3_COUNT: {
    		int timer_index = (msr - HV_X64_MSR_STIMER0_COUNT)/2;
    
    		return stimer_get_count(vcpu_to_stimer(vcpu, timer_index),
    					pdata);
    	}
    	case HV_X64_MSR_TSC_FREQUENCY:
    		data = (u64)vcpu->arch.virtual_tsc_khz * 1000;
    		break;
    	case HV_X64_MSR_APIC_FREQUENCY:
    		data = APIC_BUS_FREQUENCY;
    		break;
    	default:
    		vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr);
    		return 1;
    	}
    	*pdata = data;
    	return 0;
    }
    
    int kvm_hv_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
    {
    	if (kvm_hv_msr_partition_wide(msr)) {
    		int r;
    
    		mutex_lock(&vcpu->kvm->arch.hyperv.hv_lock);
    		r = kvm_hv_set_msr_pw(vcpu, msr, data, host);
    		mutex_unlock(&vcpu->kvm->arch.hyperv.hv_lock);
    		return r;
    	} else
    		return kvm_hv_set_msr(vcpu, msr, data, host);
    }
    
    int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host)
    {
    	if (kvm_hv_msr_partition_wide(msr)) {
    		int r;
    
    		mutex_lock(&vcpu->kvm->arch.hyperv.hv_lock);
    		r = kvm_hv_get_msr_pw(vcpu, msr, pdata, host);
    		mutex_unlock(&vcpu->kvm->arch.hyperv.hv_lock);
    		return r;
    	} else
    		return kvm_hv_get_msr(vcpu, msr, pdata, host);
    }
    
    static __always_inline unsigned long *sparse_set_to_vcpu_mask(
    	struct kvm *kvm, u64 *sparse_banks, u64 valid_bank_mask,
    	u64 *vp_bitmap, unsigned long *vcpu_bitmap)
    {
    	struct kvm_hv *hv = &kvm->arch.hyperv;
    	struct kvm_vcpu *vcpu;
    	int i, bank, sbank = 0;
    
    	memset(vp_bitmap, 0,
    	       KVM_HV_MAX_SPARSE_VCPU_SET_BITS * sizeof(*vp_bitmap));
    	for_each_set_bit(bank, (unsigned long *)&valid_bank_mask,
    			 KVM_HV_MAX_SPARSE_VCPU_SET_BITS)
    		vp_bitmap[bank] = sparse_banks[sbank++];
    
    	if (likely(!atomic_read(&hv->num_mismatched_vp_indexes))) {
    		/* for all vcpus vp_index == vcpu_idx */
    		return (unsigned long *)vp_bitmap;
    	}
    
    	bitmap_zero(vcpu_bitmap, KVM_MAX_VCPUS);
    	kvm_for_each_vcpu(i, vcpu, kvm) {
    		if (test_bit(vcpu_to_hv_vcpu(vcpu)->vp_index,
    			     (unsigned long *)vp_bitmap))
    			__set_bit(i, vcpu_bitmap);
    	}
    	return vcpu_bitmap;
    }
    
    static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
    			    u16 rep_cnt, bool ex)
    {
    	struct kvm *kvm = current_vcpu->kvm;
    	struct kvm_vcpu_hv *hv_vcpu = &current_vcpu->arch.hyperv;
    	struct hv_tlb_flush_ex flush_ex;
    	struct hv_tlb_flush flush;
    	u64 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS];
    	DECLARE_BITMAP(vcpu_bitmap, KVM_MAX_VCPUS);
    	unsigned long *vcpu_mask;
    	u64 valid_bank_mask;
    	u64 sparse_banks[64];
    	int sparse_banks_len;
    	bool all_cpus;
    
    	if (!ex) {
    		if (unlikely(kvm_read_guest(kvm, ingpa, &flush, sizeof(flush))))
    			return HV_STATUS_INVALID_HYPERCALL_INPUT;
    
    		trace_kvm_hv_flush_tlb(flush.processor_mask,
    				       flush.address_space, flush.flags);
    
    		valid_bank_mask = BIT_ULL(0);
    		sparse_banks[0] = flush.processor_mask;
    
    		/*
    		 * Work around possible WS2012 bug: it sends hypercalls
    		 * with processor_mask = 0x0 and HV_FLUSH_ALL_PROCESSORS clear,
    		 * while also expecting us to flush something and crashing if
    		 * we don't. Let's treat processor_mask == 0 same as
    		 * HV_FLUSH_ALL_PROCESSORS.
    		 */
    		all_cpus = (flush.flags & HV_FLUSH_ALL_PROCESSORS) ||
    			flush.processor_mask == 0;
    	} else {
    		if (unlikely(kvm_read_guest(kvm, ingpa, &flush_ex,
    					    sizeof(flush_ex))))
    			return HV_STATUS_INVALID_HYPERCALL_INPUT;
    
    		trace_kvm_hv_flush_tlb_ex(flush_ex.hv_vp_set.valid_bank_mask,
    					  flush_ex.hv_vp_set.format,
    					  flush_ex.address_space,
    					  flush_ex.flags);
    
    		valid_bank_mask = flush_ex.hv_vp_set.valid_bank_mask;
    		all_cpus = flush_ex.hv_vp_set.format !=
    			HV_GENERIC_SET_SPARSE_4K;
    
    		sparse_banks_len =
    			bitmap_weight((unsigned long *)&valid_bank_mask, 64) *
    			sizeof(sparse_banks[0]);
    
    		if (!sparse_banks_len && !all_cpus)
    			goto ret_success;
    
    		if (!all_cpus &&
    		    kvm_read_guest(kvm,
    				   ingpa + offsetof(struct hv_tlb_flush_ex,
    						    hv_vp_set.bank_contents),
    				   sparse_banks,
    				   sparse_banks_len))
    			return HV_STATUS_INVALID_HYPERCALL_INPUT;
    	}
    
    	cpumask_clear(&hv_vcpu->tlb_flush);
    
    	vcpu_mask = all_cpus ? NULL :
    		sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask,
    					vp_bitmap, vcpu_bitmap);
    
    	/*
    	 * vcpu->arch.cr3 may not be up-to-date for running vCPUs so we can't
    	 * analyze it here, flush TLB regardless of the specified address space.
    	 */
    	kvm_make_vcpus_request_mask(kvm, KVM_REQ_HV_TLB_FLUSH,
    				    NULL, vcpu_mask, &hv_vcpu->tlb_flush);
    
    ret_success:
    	/* We always do full TLB flush, set rep_done = rep_cnt. */
    	return (u64)HV_STATUS_SUCCESS |
    		((u64)rep_cnt << HV_HYPERCALL_REP_COMP_OFFSET);
    }
    
    static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector,
    				 unsigned long *vcpu_bitmap)
    {
    	struct kvm_lapic_irq irq = {
    		.delivery_mode = APIC_DM_FIXED,
    		.vector = vector
    	};
    	struct kvm_vcpu *vcpu;
    	int i;
    
    	kvm_for_each_vcpu(i, vcpu, kvm) {
    		if (vcpu_bitmap && !test_bit(i, vcpu_bitmap))
    			continue;
    
    		/* We fail only when APIC is disabled */
    		kvm_apic_set_irq(vcpu, &irq, NULL);
    	}
    }
    
    static u64 kvm_hv_send_ipi(struct kvm_vcpu *current_vcpu, u64 ingpa, u64 outgpa,
    			   bool ex, bool fast)
    {
    	struct kvm *kvm = current_vcpu->kvm;
    	struct hv_send_ipi_ex send_ipi_ex;
    	struct hv_send_ipi send_ipi;
    	u64 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS];
    	DECLARE_BITMAP(vcpu_bitmap, KVM_MAX_VCPUS);
    	unsigned long *vcpu_mask;
    	unsigned long valid_bank_mask;
    	u64 sparse_banks[64];
    	int sparse_banks_len;
    	u32 vector;
    	bool all_cpus;
    
    	if (!ex) {
    		if (!fast) {
    			if (unlikely(kvm_read_guest(kvm, ingpa, &send_ipi,
    						    sizeof(send_ipi))))
    				return HV_STATUS_INVALID_HYPERCALL_INPUT;
    			sparse_banks[0] = send_ipi.cpu_mask;
    			vector = send_ipi.vector;
    		} else {
    			/* 'reserved' part of hv_send_ipi should be 0 */
    			if (unlikely(ingpa >> 32 != 0))
    				return HV_STATUS_INVALID_HYPERCALL_INPUT;
    			sparse_banks[0] = outgpa;
    			vector = (u32)ingpa;
    		}
    		all_cpus = false;
    		valid_bank_mask = BIT_ULL(0);
    
    		trace_kvm_hv_send_ipi(vector, sparse_banks[0]);
    	} else {
    		if (unlikely(kvm_read_guest(kvm, ingpa, &send_ipi_ex,
    					    sizeof(send_ipi_ex))))
    			return HV_STATUS_INVALID_HYPERCALL_INPUT;
    
    		trace_kvm_hv_send_ipi_ex(send_ipi_ex.vector,
    					 send_ipi_ex.vp_set.format,
    					 send_ipi_ex.vp_set.valid_bank_mask);
    
    		vector = send_ipi_ex.vector;
    		valid_bank_mask = send_ipi_ex.vp_set.valid_bank_mask;
    		sparse_banks_len = bitmap_weight(&valid_bank_mask, 64) *
    			sizeof(sparse_banks[0]);
    
    		all_cpus = send_ipi_ex.vp_set.format == HV_GENERIC_SET_ALL;
    
    		if (!sparse_banks_len)
    			goto ret_success;
    
    		if (!all_cpus &&
    		    kvm_read_guest(kvm,
    				   ingpa + offsetof(struct hv_send_ipi_ex,
    						    vp_set.bank_contents),
    				   sparse_banks,
    				   sparse_banks_len))
    			return HV_STATUS_INVALID_HYPERCALL_INPUT;
    	}
    
    	if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
    		return HV_STATUS_INVALID_HYPERCALL_INPUT;
    
    	vcpu_mask = all_cpus ? NULL :
    		sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask,
    					vp_bitmap, vcpu_bitmap);
    
    	kvm_send_ipi_to_many(kvm, vector, vcpu_mask);
    
    ret_success:
    	return HV_STATUS_SUCCESS;
    }
    
    bool kvm_hv_hypercall_enabled(struct kvm *kvm)
    {
    	return READ_ONCE(kvm->arch.hyperv.hv_guest_os_id) != 0;
    }
    
    static void kvm_hv_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
    {
    	bool longmode;
    
    	longmode = is_64_bit_mode(vcpu);
    	if (longmode)
    		kvm_rax_write(vcpu, result);
    	else {
    		kvm_rdx_write(vcpu, result >> 32);
    		kvm_rax_write(vcpu, result & 0xffffffff);
    	}
    }
    
    static int kvm_hv_hypercall_complete(struct kvm_vcpu *vcpu, u64 result)
    {
    	kvm_hv_hypercall_set_result(vcpu, result);
    	++vcpu->stat.hypercalls;
    	return kvm_skip_emulated_instruction(vcpu);
    }
    
    static int kvm_hv_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
    {
    	return kvm_hv_hypercall_complete(vcpu, vcpu->run->hyperv.u.hcall.result);
    }
    
    static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, bool fast, u64 param)
    {
    	struct eventfd_ctx *eventfd;
    
    	if (unlikely(!fast)) {
    		int ret;
    		gpa_t gpa = param;
    
    		if ((gpa & (__alignof__(param) - 1)) ||
    		    offset_in_page(gpa) + sizeof(param) > PAGE_SIZE)
    			return HV_STATUS_INVALID_ALIGNMENT;
    
    		ret = kvm_vcpu_read_guest(vcpu, gpa, &param, sizeof(param));
    		if (ret < 0)
    			return HV_STATUS_INVALID_ALIGNMENT;
    	}
    
    	/*
    	 * Per spec, bits 32-47 contain the extra "flag number".  However, we
    	 * have no use for it, and in all known usecases it is zero, so just
    	 * report lookup failure if it isn't.
    	 */
    	if (param & 0xffff00000000ULL)
    		return HV_STATUS_INVALID_PORT_ID;
    	/* remaining bits are reserved-zero */
    	if (param & ~KVM_HYPERV_CONN_ID_MASK)
    		return HV_STATUS_INVALID_HYPERCALL_INPUT;
    
    	/* the eventfd is protected by vcpu->kvm->srcu, but conn_to_evt isn't */
    	rcu_read_lock();
    	eventfd = idr_find(&vcpu->kvm->arch.hyperv.conn_to_evt, param);
    	rcu_read_unlock();
    	if (!eventfd)
    		return HV_STATUS_INVALID_PORT_ID;
    
    	eventfd_signal(eventfd, 1);
    	return HV_STATUS_SUCCESS;
    }
    
    int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
    {
    	u64 param, ingpa, outgpa, ret = HV_STATUS_SUCCESS;
    	uint16_t code, rep_idx, rep_cnt;
    	bool fast, rep;
    
    	/*
    	 * hypercall generates UD from non zero cpl and real mode
    	 * per HYPER-V spec
    	 */
    	if (kvm_x86_ops.get_cpl(vcpu) != 0 || !is_protmode(vcpu)) {
    		kvm_queue_exception(vcpu, UD_VECTOR);
    		return 1;
    	}
    
    #ifdef CONFIG_X86_64
    	if (is_64_bit_mode(vcpu)) {
    		param = kvm_rcx_read(vcpu);
    		ingpa = kvm_rdx_read(vcpu);
    		outgpa = kvm_r8_read(vcpu);
    	} else
    #endif
    	{
    		param = ((u64)kvm_rdx_read(vcpu) << 32) |
    			(kvm_rax_read(vcpu) & 0xffffffff);
    		ingpa = ((u64)kvm_rbx_read(vcpu) << 32) |
    			(kvm_rcx_read(vcpu) & 0xffffffff);
    		outgpa = ((u64)kvm_rdi_read(vcpu) << 32) |
    			(kvm_rsi_read(vcpu) & 0xffffffff);
    	}
    
    	code = param & 0xffff;
    	fast = !!(param & HV_HYPERCALL_FAST_BIT);
    	rep_cnt = (param >> HV_HYPERCALL_REP_COMP_OFFSET) & 0xfff;
    	rep_idx = (param >> HV_HYPERCALL_REP_START_OFFSET) & 0xfff;
    	rep = !!(rep_cnt || rep_idx);
    
    	trace_kvm_hv_hypercall(code, fast, rep_cnt, rep_idx, ingpa, outgpa);
    
    	switch (code) {
    	case HVCALL_NOTIFY_LONG_SPIN_WAIT:
    		if (unlikely(rep)) {
    			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
    			break;
    		}
    		kvm_vcpu_on_spin(vcpu, true);
    		break;
    	case HVCALL_SIGNAL_EVENT:
    		if (unlikely(rep)) {
    			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
    			break;
    		}
    		ret = kvm_hvcall_signal_event(vcpu, fast, ingpa);
    		if (ret != HV_STATUS_INVALID_PORT_ID)
    			break;
    		fallthrough;	/* maybe userspace knows this conn_id */
    	case HVCALL_POST_MESSAGE:
    		/* don't bother userspace if it has no way to handle it */
    		if (unlikely(rep || !vcpu_to_synic(vcpu)->active)) {
    			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
    			break;
    		}
    		vcpu->run->exit_reason = KVM_EXIT_HYPERV;
    		vcpu->run->hyperv.type = KVM_EXIT_HYPERV_HCALL;
    		vcpu->run->hyperv.u.hcall.input = param;
    		vcpu->run->hyperv.u.hcall.params[0] = ingpa;
    		vcpu->run->hyperv.u.hcall.params[1] = outgpa;
    		vcpu->arch.complete_userspace_io =
    				kvm_hv_hypercall_complete_userspace;
    		return 0;
    	case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST:
    		if (unlikely(fast || !rep_cnt || rep_idx)) {
    			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
    			break;
    		}
    		ret = kvm_hv_flush_tlb(vcpu, ingpa, rep_cnt, false);
    		break;
    	case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE:
    		if (unlikely(fast || rep)) {
    			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
    			break;
    		}
    		ret = kvm_hv_flush_tlb(vcpu, ingpa, rep_cnt, false);
    		break;
    	case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX:
    		if (unlikely(fast || !rep_cnt || rep_idx)) {
    			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
    			break;
    		}
    		ret = kvm_hv_flush_tlb(vcpu, ingpa, rep_cnt, true);
    		break;
    	case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX:
    		if (unlikely(fast || rep)) {
    			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
    			break;
    		}
    		ret = kvm_hv_flush_tlb(vcpu, ingpa, rep_cnt, true);
    		break;
    	case HVCALL_SEND_IPI:
    		if (unlikely(rep)) {
    			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
    			break;
    		}
    		ret = kvm_hv_send_ipi(vcpu, ingpa, outgpa, false, fast);
    		break;
    	case HVCALL_SEND_IPI_EX:
    		if (unlikely(fast || rep)) {
    			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
    			break;
    		}
    		ret = kvm_hv_send_ipi(vcpu, ingpa, outgpa, true, false);
    		break;
    	case HVCALL_POST_DEBUG_DATA:
    	case HVCALL_RETRIEVE_DEBUG_DATA:
    		if (unlikely(fast)) {
    			ret = HV_STATUS_INVALID_PARAMETER;
    			break;
    		}
    		fallthrough;
    	case HVCALL_RESET_DEBUG_SESSION: {
    		struct kvm_hv_syndbg *syndbg = vcpu_to_hv_syndbg(vcpu);
    
    		if (!kvm_hv_is_syndbg_enabled(vcpu)) {
    			ret = HV_STATUS_INVALID_HYPERCALL_CODE;
    			break;
    		}
    
    		if (!(syndbg->options & HV_X64_SYNDBG_OPTION_USE_HCALLS)) {
    			ret = HV_STATUS_OPERATION_DENIED;
    			break;
    		}
    		vcpu->run->exit_reason = KVM_EXIT_HYPERV;
    		vcpu->run->hyperv.type = KVM_EXIT_HYPERV_HCALL;
    		vcpu->run->hyperv.u.hcall.input = param;
    		vcpu->run->hyperv.u.hcall.params[0] = ingpa;
    		vcpu->run->hyperv.u.hcall.params[1] = outgpa;
    		vcpu->arch.complete_userspace_io =
    				kvm_hv_hypercall_complete_userspace;
    		return 0;
    	}
    	default:
    		ret = HV_STATUS_INVALID_HYPERCALL_CODE;
    		break;
    	}
    
    	return kvm_hv_hypercall_complete(vcpu, ret);
    }
    
    void kvm_hv_init_vm(struct kvm *kvm)
    {
    	mutex_init(&kvm->arch.hyperv.hv_lock);
    	idr_init(&kvm->arch.hyperv.conn_to_evt);
    }
    
    void kvm_hv_destroy_vm(struct kvm *kvm)
    {
    	struct eventfd_ctx *eventfd;
    	int i;
    
    	idr_for_each_entry(&kvm->arch.hyperv.conn_to_evt, eventfd, i)
    		eventfd_ctx_put(eventfd);
    	idr_destroy(&kvm->arch.hyperv.conn_to_evt);
    }
    
    static int kvm_hv_eventfd_assign(struct kvm *kvm, u32 conn_id, int fd)
    {
    	struct kvm_hv *hv = &kvm->arch.hyperv;
    	struct eventfd_ctx *eventfd;
    	int ret;
    
    	eventfd = eventfd_ctx_fdget(fd);
    	if (IS_ERR(eventfd))
    		return PTR_ERR(eventfd);
    
    	mutex_lock(&hv->hv_lock);
    	ret = idr_alloc(&hv->conn_to_evt, eventfd, conn_id, conn_id + 1,
    			GFP_KERNEL_ACCOUNT);
    	mutex_unlock(&hv->hv_lock);
    
    	if (ret >= 0)
    		return 0;
    
    	if (ret == -ENOSPC)
    		ret = -EEXIST;
    	eventfd_ctx_put(eventfd);
    	return ret;
    }
    
    static int kvm_hv_eventfd_deassign(struct kvm *kvm, u32 conn_id)
    {
    	struct kvm_hv *hv = &kvm->arch.hyperv;
    	struct eventfd_ctx *eventfd;
    
    	mutex_lock(&hv->hv_lock);
    	eventfd = idr_remove(&hv->conn_to_evt, conn_id);
    	mutex_unlock(&hv->hv_lock);
    
    	if (!eventfd)
    		return -ENOENT;
    
    	synchronize_srcu(&kvm->srcu);
    	eventfd_ctx_put(eventfd);
    	return 0;
    }
    
    int kvm_vm_ioctl_hv_eventfd(struct kvm *kvm, struct kvm_hyperv_eventfd *args)
    {
    	if ((args->flags & ~KVM_HYPERV_EVENTFD_DEASSIGN) ||
    	    (args->conn_id & ~KVM_HYPERV_CONN_ID_MASK))
    		return -EINVAL;
    
    	if (args->flags == KVM_HYPERV_EVENTFD_DEASSIGN)
    		return kvm_hv_eventfd_deassign(kvm, args->conn_id);
    	return kvm_hv_eventfd_assign(kvm, args->conn_id, args->fd);
    }
    
    int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,
    				struct kvm_cpuid_entry2 __user *entries)
    {
    	uint16_t evmcs_ver = 0;
    	struct kvm_cpuid_entry2 cpuid_entries[] = {
    		{ .function = HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS },
    		{ .function = HYPERV_CPUID_INTERFACE },
    		{ .function = HYPERV_CPUID_VERSION },
    		{ .function = HYPERV_CPUID_FEATURES },
    		{ .function = HYPERV_CPUID_ENLIGHTMENT_INFO },
    		{ .function = HYPERV_CPUID_IMPLEMENT_LIMITS },
    		{ .function = HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS },
    		{ .function = HYPERV_CPUID_SYNDBG_INTERFACE },
    		{ .function = HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES	},
    		{ .function = HYPERV_CPUID_NESTED_FEATURES },
    	};
    	int i, nent = ARRAY_SIZE(cpuid_entries);
    
    	if (kvm_x86_ops.nested_ops->get_evmcs_version)
    		evmcs_ver = kvm_x86_ops.nested_ops->get_evmcs_version(vcpu);
    
    	/* Skip NESTED_FEATURES if eVMCS is not supported */
    	if (!evmcs_ver)
    		--nent;
    
    	if (cpuid->nent < nent)
    		return -E2BIG;
    
    	if (cpuid->nent > nent)
    		cpuid->nent = nent;
    
    	for (i = 0; i < nent; i++) {
    		struct kvm_cpuid_entry2 *ent = &cpuid_entries[i];
    		u32 signature[3];
    
    		switch (ent->function) {
    		case HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS:
    			memcpy(signature, "Linux KVM Hv", 12);
    
    			ent->eax = HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES;
    			ent->ebx = signature[0];
    			ent->ecx = signature[1];
    			ent->edx = signature[2];
    			break;
    
    		case HYPERV_CPUID_INTERFACE:
    			memcpy(signature, "Hv#1\0\0\0\0\0\0\0\0", 12);
    			ent->eax = signature[0];
    			break;
    
    		case HYPERV_CPUID_VERSION:
    			/*
    			 * We implement some Hyper-V 2016 functions so let's use
    			 * this version.
    			 */
    			ent->eax = 0x00003839;
    			ent->ebx = 0x000A0000;
    			break;
    
    		case HYPERV_CPUID_FEATURES:
    			ent->eax |= HV_MSR_VP_RUNTIME_AVAILABLE;
    			ent->eax |= HV_MSR_TIME_REF_COUNT_AVAILABLE;
    			ent->eax |= HV_MSR_SYNIC_AVAILABLE;
    			ent->eax |= HV_MSR_SYNTIMER_AVAILABLE;
    			ent->eax |= HV_MSR_APIC_ACCESS_AVAILABLE;
    			ent->eax |= HV_MSR_HYPERCALL_AVAILABLE;
    			ent->eax |= HV_MSR_VP_INDEX_AVAILABLE;
    			ent->eax |= HV_MSR_RESET_AVAILABLE;
    			ent->eax |= HV_MSR_REFERENCE_TSC_AVAILABLE;
    			ent->eax |= HV_ACCESS_FREQUENCY_MSRS;
    			ent->eax |= HV_ACCESS_REENLIGHTENMENT;
    
    			ent->ebx |= HV_POST_MESSAGES;
    			ent->ebx |= HV_SIGNAL_EVENTS;
    
    			ent->edx |= HV_FEATURE_FREQUENCY_MSRS_AVAILABLE;
    			ent->edx |= HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE;
    
    			ent->ebx |= HV_DEBUGGING;
    			ent->edx |= HV_X64_GUEST_DEBUGGING_AVAILABLE;
    			ent->edx |= HV_FEATURE_DEBUG_MSRS_AVAILABLE;
    
    			/*
    			 * Direct Synthetic timers only make sense with in-kernel
    			 * LAPIC
    			 */
    			if (lapic_in_kernel(vcpu))
    				ent->edx |= HV_STIMER_DIRECT_MODE_AVAILABLE;
    
    			break;
    
    		case HYPERV_CPUID_ENLIGHTMENT_INFO:
    			ent->eax |= HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED;
    			ent->eax |= HV_X64_APIC_ACCESS_RECOMMENDED;
    			ent->eax |= HV_X64_RELAXED_TIMING_RECOMMENDED;
    			ent->eax |= HV_X64_CLUSTER_IPI_RECOMMENDED;
    			ent->eax |= HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED;
    			if (evmcs_ver)
    				ent->eax |= HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
    			if (!cpu_smt_possible())
    				ent->eax |= HV_X64_NO_NONARCH_CORESHARING;
    			/*
    			 * Default number of spinlock retry attempts, matches
    			 * HyperV 2016.
    			 */
    			ent->ebx = 0x00000FFF;
    
    			break;
    
    		case HYPERV_CPUID_IMPLEMENT_LIMITS:
    			/* Maximum number of virtual processors */
    			ent->eax = KVM_MAX_VCPUS;
    			/*
    			 * Maximum number of logical processors, matches
    			 * HyperV 2016.
    			 */
    			ent->ebx = 64;
    
    			break;
    
    		case HYPERV_CPUID_NESTED_FEATURES:
    			ent->eax = evmcs_ver;
    
    			break;
    
    		case HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS:
    			memcpy(signature, "Linux KVM Hv", 12);
    
    			ent->eax = 0;
    			ent->ebx = signature[0];
    			ent->ecx = signature[1];
    			ent->edx = signature[2];
    			break;
    
    		case HYPERV_CPUID_SYNDBG_INTERFACE:
    			memcpy(signature, "VS#1\0\0\0\0\0\0\0\0", 12);
    			ent->eax = signature[0];
    			break;
    
    		case HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES:
    			ent->eax |= HV_X64_SYNDBG_CAP_ALLOW_KERNEL_DEBUGGING;
    			break;
    
    		default:
    			break;
    		}
    	}
    
    	if (copy_to_user(entries, cpuid_entries,
    			 nent * sizeof(struct kvm_cpuid_entry2)))
    		return -EFAULT;
    
    	return 0;
    }