arch/x86/kvm/hyperv.c - third_party/linux - Git at Google

 /*
  * 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>
  *
  * This work is licensed under the terms of the GNU GPL, version 2.  See
  * the COPYING file in the top-level directory.
  *
  */

 #include "x86.h"
 #include "lapic.h"
 #include "hyperv.h"

 #include <linux/kvm_host.h>
 #include <trace/events/kvm.h>

 #include "trace.h"

 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:
 		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;

 	if (WARN_ON_ONCE(index >= ARRAY_SIZE(hv->hv_crash_param)))
 		return -EINVAL;

 	*pdata = hv->hv_crash_param[index];
 	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_X64_MSR_CRASH_CTL_NOTIFY;

 	if (!host && (data & HV_X64_MSR_CRASH_CTL_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;

 	if (WARN_ON_ONCE(index >= ARRAY_SIZE(hv->hv_crash_param)))
 		return -EINVAL;

 	hv->hv_crash_param[index] = data;
 	return 0;
 }

 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: {
 		u64 gfn;
 		HV_REFERENCE_TSC_PAGE tsc_ref;

 		memset(&tsc_ref, 0, sizeof(tsc_ref));
 		hv->hv_tsc_page = data;
 		if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE))
 			break;
 		gfn = data >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
 		if (kvm_write_guest(
 				kvm,
 				gfn << HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT,
 				&tsc_ref, sizeof(tsc_ref)))
 			return 1;
 		mark_page_dirty(kvm, gfn);
 		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;
 	default:
 		vcpu_unimpl(vcpu, "Hyper-V uhandled 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)
 {
 	cputime_t utime, stime;

 	task_cputime_adjusted(current, &utime, &stime);
 	return div_u64(cputime_to_nsecs(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->arch.hyperv;

 	switch (msr) {
 	case HV_X64_MSR_APIC_ASSIST_PAGE: {
 		u64 gfn;
 		unsigned long addr;

 		if (!(data & HV_X64_MSR_APIC_ASSIST_PAGE_ENABLE)) {
 			hv->hv_vapic = data;
 			if (kvm_lapic_enable_pv_eoi(vcpu, 0))
 				return 1;
 			break;
 		}
 		gfn = data >> HV_X64_MSR_APIC_ASSIST_PAGE_ADDRESS_SHIFT;
 		addr = kvm_vcpu_gfn_to_hva(vcpu, gfn);
 		if (kvm_is_error_hva(addr))
 			return 1;
 		if (__clear_user((void __user *)addr, PAGE_SIZE))
 			return 1;
 		hv->hv_vapic = data;
 		kvm_vcpu_mark_page_dirty(vcpu, gfn);
 		if (kvm_lapic_enable_pv_eoi(vcpu,
 					    gfn_to_gpa(gfn) | KVM_MSR_ENABLED))
 			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->runtime_offset = data - current_task_runtime_100ns();
 		break;
 	default:
 		vcpu_unimpl(vcpu, "Hyper-V uhandled 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)
 {
 	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 =
 		     div_u64(get_kernel_ns() + kvm->arch.kvmclock_offset, 100);
 		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;
 	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)
 {
 	u64 data = 0;
 	struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv;

 	switch (msr) {
 	case HV_X64_MSR_VP_INDEX: {
 		int r;
 		struct kvm_vcpu *v;

 		kvm_for_each_vcpu(r, v, vcpu->kvm) {
 			if (v == vcpu) {
 				data = r;
 				break;
 			}
 		}
 		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_APIC_ASSIST_PAGE:
 		data = hv->hv_vapic;
 		break;
 	case HV_X64_MSR_VP_RUNTIME:
 		data = current_task_runtime_100ns() + hv->runtime_offset;
 		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->lock);
 		r = kvm_hv_set_msr_pw(vcpu, msr, data, host);
 		mutex_unlock(&vcpu->kvm->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)
 {
 	if (kvm_hv_msr_partition_wide(msr)) {
 		int r;

 		mutex_lock(&vcpu->kvm->lock);
 		r = kvm_hv_get_msr_pw(vcpu, msr, pdata);
 		mutex_unlock(&vcpu->kvm->lock);
 		return r;
 	} else
 		return kvm_hv_get_msr(vcpu, msr, pdata);
 }

 bool kvm_hv_hypercall_enabled(struct kvm *kvm)
 {
 	return kvm->arch.hyperv.hv_hypercall & HV_X64_MSR_HYPERCALL_ENABLE;
 }

 int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
 {
 	u64 param, ingpa, outgpa, ret;
 	uint16_t code, rep_idx, rep_cnt, res = HV_STATUS_SUCCESS, rep_done = 0;
 	bool fast, longmode;

 	/*
 	 * 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 0;
 	}

 	longmode = is_64_bit_mode(vcpu);

 	if (!longmode) {
 		param = ((u64)kvm_register_read(vcpu, VCPU_REGS_RDX) << 32) |
 			(kvm_register_read(vcpu, VCPU_REGS_RAX) & 0xffffffff);
 		ingpa = ((u64)kvm_register_read(vcpu, VCPU_REGS_RBX) << 32) |
 			(kvm_register_read(vcpu, VCPU_REGS_RCX) & 0xffffffff);
 		outgpa = ((u64)kvm_register_read(vcpu, VCPU_REGS_RDI) << 32) |
 			(kvm_register_read(vcpu, VCPU_REGS_RSI) & 0xffffffff);
 	}
 #ifdef CONFIG_X86_64
 	else {
 		param = kvm_register_read(vcpu, VCPU_REGS_RCX);
 		ingpa = kvm_register_read(vcpu, VCPU_REGS_RDX);
 		outgpa = kvm_register_read(vcpu, VCPU_REGS_R8);
 	}
 #endif

 	code = param & 0xffff;
 	fast = (param >> 16) & 0x1;
 	rep_cnt = (param >> 32) & 0xfff;
 	rep_idx = (param >> 48) & 0xfff;

 	trace_kvm_hv_hypercall(code, fast, rep_cnt, rep_idx, ingpa, outgpa);

 	switch (code) {
 	case HV_X64_HV_NOTIFY_LONG_SPIN_WAIT:
 		kvm_vcpu_on_spin(vcpu);
 		break;
 	default:
 		res = HV_STATUS_INVALID_HYPERCALL_CODE;
 		break;
 	}

 	ret = res | (((u64)rep_done & 0xfff) << 32);
 	if (longmode) {
 		kvm_register_write(vcpu, VCPU_REGS_RAX, ret);
 	} else {
 		kvm_register_write(vcpu, VCPU_REGS_RDX, ret >> 32);
 		kvm_register_write(vcpu, VCPU_REGS_RAX, ret & 0xffffffff);
 	}

 	return 1;
 }
	/*
	* 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>
	*
	* This work is licensed under the terms of the GNU GPL, version 2. See
	* the COPYING file in the top-level directory.
	*
	*/

	#include "x86.h"
	#include "lapic.h"
	#include "hyperv.h"

	#include <linux/kvm_host.h>
	#include <trace/events/kvm.h>

	#include "trace.h"

	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:
	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;

	if (WARN_ON_ONCE(index >= ARRAY_SIZE(hv->hv_crash_param)))
	return -EINVAL;

	*pdata = hv->hv_crash_param[index];
	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_X64_MSR_CRASH_CTL_NOTIFY;

	if (!host && (data & HV_X64_MSR_CRASH_CTL_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;

	if (WARN_ON_ONCE(index >= ARRAY_SIZE(hv->hv_crash_param)))
	return -EINVAL;

	hv->hv_crash_param[index] = data;
	return 0;
	}

	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: {
	u64 gfn;
	HV_REFERENCE_TSC_PAGE tsc_ref;

	memset(&tsc_ref, 0, sizeof(tsc_ref));
	hv->hv_tsc_page = data;
	if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE))
	break;
	gfn = data >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
	if (kvm_write_guest(
	kvm,
	gfn << HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT,
	&tsc_ref, sizeof(tsc_ref)))
	return 1;
	mark_page_dirty(kvm, gfn);
	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;
	default:
	vcpu_unimpl(vcpu, "Hyper-V uhandled 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)
	{
	cputime_t utime, stime;

	task_cputime_adjusted(current, &utime, &stime);
	return div_u64(cputime_to_nsecs(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->arch.hyperv;

	switch (msr) {
	case HV_X64_MSR_APIC_ASSIST_PAGE: {
	u64 gfn;
	unsigned long addr;

	if (!(data & HV_X64_MSR_APIC_ASSIST_PAGE_ENABLE)) {
	hv->hv_vapic = data;
	if (kvm_lapic_enable_pv_eoi(vcpu, 0))
	return 1;
	break;
	}
	gfn = data >> HV_X64_MSR_APIC_ASSIST_PAGE_ADDRESS_SHIFT;
	addr = kvm_vcpu_gfn_to_hva(vcpu, gfn);
	if (kvm_is_error_hva(addr))
	return 1;
	if (__clear_user((void __user *)addr, PAGE_SIZE))
	return 1;
	hv->hv_vapic = data;
	kvm_vcpu_mark_page_dirty(vcpu, gfn);
	if (kvm_lapic_enable_pv_eoi(vcpu,
	gfn_to_gpa(gfn) \| KVM_MSR_ENABLED))
	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->runtime_offset = data - current_task_runtime_100ns();
	break;
	default:
	vcpu_unimpl(vcpu, "Hyper-V uhandled 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)
	{
	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 =
	div_u64(get_kernel_ns() + kvm->arch.kvmclock_offset, 100);
	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;
	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)
	{
	u64 data = 0;
	struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv;

	switch (msr) {
	case HV_X64_MSR_VP_INDEX: {
	int r;
	struct kvm_vcpu *v;

	kvm_for_each_vcpu(r, v, vcpu->kvm) {
	if (v == vcpu) {
	data = r;
	break;
	}
	}
	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_APIC_ASSIST_PAGE:
	data = hv->hv_vapic;
	break;
	case HV_X64_MSR_VP_RUNTIME:
	data = current_task_runtime_100ns() + hv->runtime_offset;
	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->lock);
	r = kvm_hv_set_msr_pw(vcpu, msr, data, host);
	mutex_unlock(&vcpu->kvm->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)
	{
	if (kvm_hv_msr_partition_wide(msr)) {
	int r;

	mutex_lock(&vcpu->kvm->lock);
	r = kvm_hv_get_msr_pw(vcpu, msr, pdata);
	mutex_unlock(&vcpu->kvm->lock);
	return r;
	} else
	return kvm_hv_get_msr(vcpu, msr, pdata);
	}

	bool kvm_hv_hypercall_enabled(struct kvm *kvm)
	{
	return kvm->arch.hyperv.hv_hypercall & HV_X64_MSR_HYPERCALL_ENABLE;
	}

	int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
	{
	u64 param, ingpa, outgpa, ret;
	uint16_t code, rep_idx, rep_cnt, res = HV_STATUS_SUCCESS, rep_done = 0;
	bool fast, longmode;

	/*
	* 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 0;
	}

	longmode = is_64_bit_mode(vcpu);

	if (!longmode) {
	param = ((u64)kvm_register_read(vcpu, VCPU_REGS_RDX) << 32) \|
	(kvm_register_read(vcpu, VCPU_REGS_RAX) & 0xffffffff);
	ingpa = ((u64)kvm_register_read(vcpu, VCPU_REGS_RBX) << 32) \|
	(kvm_register_read(vcpu, VCPU_REGS_RCX) & 0xffffffff);
	outgpa = ((u64)kvm_register_read(vcpu, VCPU_REGS_RDI) << 32) \|
	(kvm_register_read(vcpu, VCPU_REGS_RSI) & 0xffffffff);
	}
	#ifdef CONFIG_X86_64
	else {
	param = kvm_register_read(vcpu, VCPU_REGS_RCX);
	ingpa = kvm_register_read(vcpu, VCPU_REGS_RDX);
	outgpa = kvm_register_read(vcpu, VCPU_REGS_R8);
	}
	#endif

	code = param & 0xffff;
	fast = (param >> 16) & 0x1;
	rep_cnt = (param >> 32) & 0xfff;
	rep_idx = (param >> 48) & 0xfff;

	trace_kvm_hv_hypercall(code, fast, rep_cnt, rep_idx, ingpa, outgpa);

	switch (code) {
	case HV_X64_HV_NOTIFY_LONG_SPIN_WAIT:
	kvm_vcpu_on_spin(vcpu);
	break;
	default:
	res = HV_STATUS_INVALID_HYPERCALL_CODE;
	break;
	}

	ret = res \| (((u64)rep_done & 0xfff) << 32);
	if (longmode) {
	kvm_register_write(vcpu, VCPU_REGS_RAX, ret);
	} else {
	kvm_register_write(vcpu, VCPU_REGS_RDX, ret >> 32);
	kvm_register_write(vcpu, VCPU_REGS_RAX, ret & 0xffffffff);
	}

	return 1;
	}