From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Subject: [PATCH 1/2] KVM: x86/pmu: mask the result of rdpmc according to the width of the counters
Date: Mon, 20 May 2019 17:42:30 +0200 [thread overview]
Message-ID: <1558366951-19259-2-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1558366951-19259-1-git-send-email-pbonzini@redhat.com>
This patch will simplify the changes in the next, by enforcing the
masking of the counters to RDPMC and RDMSR.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/pmu.c | 10 +++-------
arch/x86/kvm/pmu.h | 3 ++-
arch/x86/kvm/pmu_amd.c | 2 +-
arch/x86/kvm/vmx/pmu_intel.c | 13 +++++++++----
4 files changed, 15 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index e39741997893..dd745b58ffd8 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -283,7 +283,7 @@ int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
bool fast_mode = idx & (1u << 31);
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct kvm_pmc *pmc;
- u64 ctr_val;
+ u64 mask = fast_mode ? ~0u : ~0ull;
if (!pmu->version)
return 1;
@@ -291,15 +291,11 @@ int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
if (is_vmware_backdoor_pmc(idx))
return kvm_pmu_rdpmc_vmware(vcpu, idx, data);
- pmc = kvm_x86_ops->pmu_ops->msr_idx_to_pmc(vcpu, idx);
+ pmc = kvm_x86_ops->pmu_ops->msr_idx_to_pmc(vcpu, idx, &mask);
if (!pmc)
return 1;
- ctr_val = pmc_read_counter(pmc);
- if (fast_mode)
- ctr_val = (u32)ctr_val;
-
- *data = ctr_val;
+ *data = pmc_read_counter(pmc) & mask;
return 0;
}
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index ba8898e1a854..22dff661145a 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -25,7 +25,8 @@ struct kvm_pmu_ops {
unsigned (*find_fixed_event)(int idx);
bool (*pmc_is_enabled)(struct kvm_pmc *pmc);
struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx);
- struct kvm_pmc *(*msr_idx_to_pmc)(struct kvm_vcpu *vcpu, unsigned idx);
+ struct kvm_pmc *(*msr_idx_to_pmc)(struct kvm_vcpu *vcpu, unsigned idx,
+ u64 *mask);
int (*is_valid_msr_idx)(struct kvm_vcpu *vcpu, unsigned idx);
bool (*is_valid_msr)(struct kvm_vcpu *vcpu, u32 msr);
int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr, u64 *data);
diff --git a/arch/x86/kvm/pmu_amd.c b/arch/x86/kvm/pmu_amd.c
index 1495a735b38e..41dff881e0f0 100644
--- a/arch/x86/kvm/pmu_amd.c
+++ b/arch/x86/kvm/pmu_amd.c
@@ -186,7 +186,7 @@ static int amd_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx)
}
/* idx is the ECX register of RDPMC instruction */
-static struct kvm_pmc *amd_msr_idx_to_pmc(struct kvm_vcpu *vcpu, unsigned idx)
+static struct kvm_pmc *amd_msr_idx_to_pmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *mask)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct kvm_pmc *counters;
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index f8502c376b37..b6f5157445fe 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -126,7 +126,7 @@ static int intel_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx)
}
static struct kvm_pmc *intel_msr_idx_to_pmc(struct kvm_vcpu *vcpu,
- unsigned idx)
+ unsigned idx, u64 *mask)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
bool fixed = idx & (1u << 30);
@@ -138,6 +138,7 @@ static struct kvm_pmc *intel_msr_idx_to_pmc(struct kvm_vcpu *vcpu,
if (fixed && idx >= pmu->nr_arch_fixed_counters)
return NULL;
counters = fixed ? pmu->fixed_counters : pmu->gp_counters;
+ *mask &= pmu->counter_bitmask[fixed ? KVM_PMC_FIXED : KVM_PMC_GP];
return &counters[idx];
}
@@ -183,9 +184,13 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
*data = pmu->global_ovf_ctrl;
return 0;
default:
- if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) ||
- (pmc = get_fixed_pmc(pmu, msr))) {
- *data = pmc_read_counter(pmc);
+ if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0))) {
+ u64 val = pmc_read_counter(pmc);
+ *data = val & pmu->counter_bitmask[KVM_PMC_GP];
+ return 0;
+ } else if ((pmc = get_fixed_pmc(pmu, msr))) {
+ u64 val = pmc_read_counter(pmc);
+ *data = val & pmu->counter_bitmask[KVM_PMC_FIXED];
return 0;
} else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) {
*data = pmc->eventsel;
--
1.8.3.1
next prev parent reply other threads:[~2019-05-20 15:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-20 15:42 [PATCH 0/2] KVM: x86/pmu: do not mask the value that is written to fixed PMUs Paolo Bonzini
2019-05-20 15:42 ` Paolo Bonzini [this message]
2019-05-20 15:42 ` [PATCH 2/2] " Paolo Bonzini
2019-05-20 19:01 ` Sean Christopherson
2019-05-22 10:27 ` Paolo Bonzini
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