In order to migrate the PMU state correctly, we need to restore the
values of MSR_CORE_PERF_GLOBAL_STATUS (a read-only register) and
MSR_CORE_PERF_GLOBAL_OVF_CTRL (which has side effects when written).
We also need to write the full 40-bit value of the performance counter,
> which would only be possible with a v3 architectural PMU's
> full-width counter MSRs.
>
> To distinguish host-initiated writes from the guest's, pass the
> full struct msr_data to kvm_pmu_set_msr.
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/pmu.c | 14 +++++++++++---
arch/x86/kvm/x86.c | 4 ++--
3 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 36fba01..e2e09f3 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1029,7 +1029,7 @@ void kvm_pmu_reset(struct kvm_vcpu *vcpu);
void kvm_pmu_cpuid_update(struct kvm_vcpu *vcpu);
bool kvm_pmu_msr(struct kvm_vcpu *vcpu, u32 msr);
int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data);
-int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data);
+int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
int kvm_pmu_read_pmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data);
void kvm_handle_pmu_event(struct kvm_vcpu *vcpu);
void kvm_deliver_pmi(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index cfc258a..c53e797 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -360,10 +360,12 @@ int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data)
return 1;
}
-int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data)
+int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
+ u32 index = msr_info->index;
+ u64 data = msr_info->data;
switch (index) {
case MSR_CORE_PERF_FIXED_CTR_CTRL:
@@ -375,6 +377,10 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data)
}
break;
case MSR_CORE_PERF_GLOBAL_STATUS:
+ if (msr_info->host_initiated) {
+ pmu->global_status = data;
+ return 0;
+ }
break; /* RO MSR */
case MSR_CORE_PERF_GLOBAL_CTRL:
if (pmu->global_ctrl == data)
@@ -386,7 +392,8 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data)
break;
case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
if (!(data & (pmu->global_ctrl_mask & ~(3ull<<62)))) {
- pmu->global_status &= ~data;
+ if (!msr_info->host_initiated)
+ pmu->global_status &= ~data;
pmu->global_ovf_ctrl = data;
return 0;
}
@@ -394,7 +401,8 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data)
default:
if ((pmc = get_gp_pmc(pmu, index, MSR_IA32_PERFCTR0)) ||
(pmc = get_fixed_pmc(pmu, index))) {
- data = (s64)(s32)data;
+ if (!msr_info->host_initiated)
+ data = (s64)(s32)data;
pmc->counter += data - read_pmc(pmc);
return 0;
} else if ((pmc = get_gp_pmc(pmu, index, MSR_P6_EVNTSEL0))) {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3e0a8ba..1d928af 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2042,7 +2042,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_P6_EVNTSEL0:
case MSR_P6_EVNTSEL1:
if (kvm_pmu_msr(vcpu, msr))
- return kvm_pmu_set_msr(vcpu, msr, data);
+ return kvm_pmu_set_msr(vcpu, msr_info);
if (pr || data != 0)
vcpu_unimpl(vcpu, "disabled perfctr wrmsr: "
@@ -2088,7 +2088,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
if (msr && (msr == vcpu->kvm->arch.xen_hvm_config.msr))
return xen_hvm_config(vcpu, data);
if (kvm_pmu_msr(vcpu, msr))
- return kvm_pmu_set_msr(vcpu, msr, data);
+ return kvm_pmu_set_msr(vcpu, msr_info);
if (!ignore_msrs) {
vcpu_unimpl(vcpu, "unhandled wrmsr: 0x%x data %llx\n",
msr, data);
--
1.8.1.4
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