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Message-Id: <20210108013704.134985-11-like.xu@linux.intel.com>
Date: Fri, 8 Jan 2021 09:37:04 +0800
From: Like Xu <like.xu@...ux.intel.com>
To: Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Joerg Roedel <joro@...tes.org>
Cc: Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Borislav Petkov <bp@...en8.de>,
"H . Peter Anvin" <hpa@...or.com>, ak@...ux.intel.com,
wei.w.wang@...el.com, kan.liang@...el.com, x86@...nel.org,
kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RESEND v13 10/10] KVM: vmx/pmu: Release guest LBR event via lazy release mechanism
The vPMU uses GUEST_LBR_IN_USE_IDX (bit 58) in 'pmu->pmc_in_use' to
indicate whether a guest LBR event is still needed by the vcpu. If the
vcpu no longer accesses LBR related registers within a scheduling time
slice, and the enable bit of LBR has been unset, vPMU will treat the
guest LBR event as a bland event of a vPMC counter and release it
as usual. Also, the pass-through state of LBR records msrs is cancelled.
Signed-off-by: Like Xu <like.xu@...ux.intel.com>
Reviewed-by: Andi Kleen <ak@...ux.intel.com>
---
arch/x86/kvm/pmu.c | 7 +++++++
arch/x86/kvm/pmu.h | 4 ++++
arch/x86/kvm/vmx/pmu_intel.c | 17 ++++++++++++++++-
3 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 405890c723a1..e7c72eea07d4 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -463,6 +463,7 @@ void kvm_pmu_cleanup(struct kvm_vcpu *vcpu)
struct kvm_pmc *pmc = NULL;
DECLARE_BITMAP(bitmask, X86_PMC_IDX_MAX);
int i;
+ bool extra_cleanup = false;
pmu->need_cleanup = false;
@@ -474,8 +475,14 @@ void kvm_pmu_cleanup(struct kvm_vcpu *vcpu)
if (pmc && pmc->perf_event && !pmc_speculative_in_use(pmc))
pmc_stop_counter(pmc);
+
+ if (i == INTEL_GUEST_LBR_INUSE)
+ extra_cleanup = true;
}
+ if (extra_cleanup && kvm_x86_ops.pmu_ops->cleanup)
+ kvm_x86_ops.pmu_ops->cleanup(vcpu);
+
bitmap_zero(pmu->pmc_in_use, X86_PMC_IDX_MAX);
}
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 742a4e98df8c..c8b650866f56 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -15,6 +15,9 @@
#define VMWARE_BACKDOOR_PMC_REAL_TIME 0x10001
#define VMWARE_BACKDOOR_PMC_APPARENT_TIME 0x10002
+/* Indicates whether Intel LBR msrs were accessed during the last time slice. */
+#define INTEL_GUEST_LBR_INUSE INTEL_PMC_IDX_FIXED_VLBR
+
#define MAX_FIXED_COUNTERS 3
struct kvm_event_hw_type_mapping {
@@ -40,6 +43,7 @@ struct kvm_pmu_ops {
void (*init)(struct kvm_vcpu *vcpu);
void (*reset)(struct kvm_vcpu *vcpu);
void (*deliver_pmi)(struct kvm_vcpu *vcpu);
+ void (*cleanup)(struct kvm_vcpu *vcpu);
};
static inline u64 pmc_bitmask(struct kvm_pmc *pmc)
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 8120685c43d4..4d10f564607d 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -310,6 +310,7 @@ int intel_pmu_create_guest_lbr_event(struct kvm_vcpu *vcpu)
}
lbr_desc->event = event;
vcpu_to_pmu(vcpu)->event_count++;
+ __set_bit(INTEL_GUEST_LBR_INUSE, vcpu_to_pmu(vcpu)->pmc_in_use);
return 0;
}
@@ -342,10 +343,12 @@ static bool intel_pmu_handle_lbr_msrs_access(struct kvm_vcpu *vcpu,
rdmsrl(index, msr_info->data);
else
wrmsrl(index, msr_info->data);
+ __set_bit(INTEL_GUEST_LBR_INUSE, vcpu_to_pmu(vcpu)->pmc_in_use);
local_irq_enable();
return true;
}
local_irq_enable();
+ clear_bit(INTEL_GUEST_LBR_INUSE, vcpu_to_pmu(vcpu)->pmc_in_use);
dummy:
if (read)
@@ -496,7 +499,8 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
if (!intel_pmu_lbr_is_enabled(vcpu)) {
vcpu->arch.perf_capabilities &= ~PMU_CAP_LBR_FMT;
lbr_desc->records.nr = 0;
- }
+ } else
+ bitmap_set(pmu->all_valid_pmc_idx, INTEL_GUEST_LBR_INUSE, 1);
pmu->nr_arch_gp_counters = min_t(int, eax.split.num_counters,
x86_pmu.num_counters_gp);
@@ -669,17 +673,21 @@ static inline void vmx_enable_lbr_msrs_passthrough(struct kvm_vcpu *vcpu)
*/
void vmx_passthrough_lbr_msrs(struct kvm_vcpu *vcpu)
{
+ struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
if (!lbr_desc->event) {
vmx_disable_lbr_msrs_passthrough(vcpu);
if (vmcs_read64(GUEST_IA32_DEBUGCTL) & DEBUGCTLMSR_LBR)
goto warn;
+ if (test_bit(INTEL_GUEST_LBR_INUSE, pmu->pmc_in_use))
+ goto warn;
return;
}
if (lbr_desc->event->state < PERF_EVENT_STATE_ACTIVE) {
vmx_disable_lbr_msrs_passthrough(vcpu);
+ __clear_bit(INTEL_GUEST_LBR_INUSE, pmu->pmc_in_use);
goto warn;
} else
vmx_enable_lbr_msrs_passthrough(vcpu);
@@ -691,6 +699,12 @@ void vmx_passthrough_lbr_msrs(struct kvm_vcpu *vcpu)
vcpu->vcpu_id);
}
+static void intel_pmu_cleanup(struct kvm_vcpu *vcpu)
+{
+ if (!(vmcs_read64(GUEST_IA32_DEBUGCTL) & DEBUGCTLMSR_LBR))
+ intel_pmu_release_guest_lbr_event(vcpu);
+}
+
struct kvm_pmu_ops intel_pmu_ops = {
.find_arch_event = intel_find_arch_event,
.find_fixed_event = intel_find_fixed_event,
@@ -706,4 +720,5 @@ struct kvm_pmu_ops intel_pmu_ops = {
.init = intel_pmu_init,
.reset = intel_pmu_reset,
.deliver_pmi = intel_pmu_deliver_pmi,
+ .cleanup = intel_pmu_cleanup,
};
--
2.29.2
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