From: Andrey Smetanin <asmetanin@xxxxxxxxxxxxx>
HV_X64_MSR_RESET msr is used by Hyper-V based Windows guest
to reset guest VM by hypervisor.
Necessary to support loading of winhv.sys in guest, which in turn is
required to support Windows VMBus.
Signed-off-by: Andrey Smetanin <asmetanin@xxxxxxxxxxxxx>
Reviewed-by: Roman Kagan <rkagan@xxxxxxxxxxxxx>
Signed-off-by: Denis V. Lunev <den@xxxxxxxxxx>
CC: Paolo Bonzini <pbonzini@xxxxxxxxxx>
CC: Gleb Natapov <gleb@xxxxxxxxxx>
---
arch/x86/include/uapi/asm/hyperv.h | 3 +++
arch/x86/kvm/hyperv.c | 10 ++++++++++
arch/x86/kvm/x86.c | 7 +++++++
include/linux/kvm_host.h | 1 +
4 files changed, 21 insertions(+)
diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
index f0412c5..dab584b 100644
--- a/arch/x86/include/uapi/asm/hyperv.h
+++ b/arch/x86/include/uapi/asm/hyperv.h
@@ -153,6 +153,9 @@
/* MSR used to provide vcpu index */
#define HV_X64_MSR_VP_INDEX 0x40000002
+/* MSR used to reset the guest OS. */
+#define HV_X64_MSR_RESET 0x40000003
+
/* MSR used to read the per-partition time reference counter */
#define HV_X64_MSR_TIME_REF_COUNT 0x40000020
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index a8160d2..0ad11a2 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -41,6 +41,7 @@ static bool kvm_hv_msr_partition_wide(u32 msr)
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;
}
@@ -163,6 +164,12 @@ static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data,
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);
@@ -241,6 +248,9 @@ static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
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;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a60bdbc..5a14a66 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -951,6 +951,7 @@ static u32 emulated_msrs[] = {
HV_X64_MSR_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC,
HV_X64_MSR_CRASH_P0, HV_X64_MSR_CRASH_P1, HV_X64_MSR_CRASH_P2,
HV_X64_MSR_CRASH_P3, HV_X64_MSR_CRASH_P4, HV_X64_MSR_CRASH_CTL,
+ HV_X64_MSR_RESET,
HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
MSR_KVM_PV_EOI_EN,
@@ -6268,6 +6269,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
r = 0;
goto out;
}
+ if (kvm_check_request(KVM_REQ_HV_RESET, vcpu)) {
+ vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
+ vcpu->run->system_event.type = KVM_SYSTEM_EVENT_RESET;
+ r = 0;
+ goto out;
+ }
}
if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 1bef9e2..f6beba2 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -140,6 +140,7 @@ static inline bool is_error_page(struct page *page)
#define KVM_REQ_APIC_PAGE_RELOAD 25
#define KVM_REQ_SMI 26
#define KVM_REQ_HV_CRASH 27
+#define KVM_REQ_HV_RESET 28
#define KVM_USERSPACE_IRQ_SOURCE_ID 0
#define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID 1
--
2.1.4
--
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