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Commit afd80d85 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Gleb Natapov
Browse files

pmu: prepare for migration support 



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: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent e1e2e605

arch/x86/include/asm/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -1030,7 +1030,7 @@ 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);

arch/x86/kvm/pmu.c

+11 −3
Original line number Diff line number Diff line
@@ -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)
@@ -386,6 +392,7 @@ 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)))) {

			if (!msr_info->host_initiated)

				pmu->global_status &= ~data;

			pmu->global_ovf_ctrl = data;

			return 0;
@@ -394,6 +401,7 @@ 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))) {

			if (!msr_info->host_initiated)

				data = (s64)(s32)data;

			pmc->counter += data - read_pmc(pmc);

			return 0;

arch/x86/kvm/x86.c

+2 −2
Original line number Diff line number Diff line
@@ -2040,7 +2040,7 @@ 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: "
@@ -2086,7 +2086,7 @@ 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);