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From: Like Xu <like.xu@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	eranian@google.com, kvm@vger.kernel.org
Cc: Ingo Molnar <mingo@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Andi Kleen <andi@firstfloor.org>,
	Kan Liang <kan.liang@linux.intel.com>,
	wei.w.wang@intel.com, luwei.kang@intel.com,
	linux-kernel@vger.kernel.org
Subject: [PATCH v3 16/17] KVM: x86/pmu: Save guest pebs reset values when pebs is configured
Date: Mon,  4 Jan 2021 21:15:41 +0800	[thread overview]
Message-ID: <20210104131542.495413-17-like.xu@linux.intel.com> (raw)
In-Reply-To: <20210104131542.495413-1-like.xu@linux.intel.com>

The guest pebs counter X may be cross mapped to the host counter Y.
While the PEBS facility would reload the reset value once a PEBS record
is written to guest DS and potentially continue to generate PEBS records
before guest read the previous records.

KVM will adjust the guest DS pebs reset counter values for exactly mapped
host counters but before that, it needs to save the original expected guest
reset counter values right after the counter is fully enabled via a trap.

We assume that every time the guest PEBS driver enables the counter for
large PEBS, it will configure the DS reset counter values as Linux does.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
---
 arch/x86/include/asm/kvm_host.h |  2 ++
 arch/x86/kvm/vmx/pmu_intel.c    | 47 ++++++++++++++++++++++++++++++---
 2 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e6394ac54f81..1d17e51c5c8a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -418,6 +418,7 @@ struct kvm_pmc {
 	enum pmc_type type;
 	u8 idx;
 	u64 counter;
+	u64 reset_counter;
 	u64 eventsel;
 	struct perf_event *perf_event;
 	struct kvm_vcpu *vcpu;
@@ -461,6 +462,7 @@ struct kvm_pmu {
 	bool counter_cross_mapped;
 	bool need_rewrite_ds_pebs_interrupt_threshold;
 	bool need_rewrite_pebs_records;
+	bool need_save_reset_counter;
 
 	/*
 	 * The gate to release perf_events not marked in
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 4c095c31db38..4e6ed0e8bddf 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -219,12 +219,14 @@ static void intel_pmu_pebs_setup(struct kvm_pmu *pmu)
 	gpa_t gpa;
 
 	pmu->need_rewrite_ds_pebs_interrupt_threshold = false;
+	pmu->need_save_reset_counter = false;
 
 	for_each_set_bit(bit, (unsigned long *)&pmu->pebs_enable, X86_PMC_IDX_MAX) {
 		pmc = kvm_x86_ops.pmu_ops->pmc_idx_to_pmc(pmu, bit);
 
 		if (pmc && pmc_speculative_in_use(pmc)) {
 			pmu->need_rewrite_ds_pebs_interrupt_threshold = true;
+			pmu->need_save_reset_counter = true;
 			break;
 		}
 	}
@@ -624,10 +626,44 @@ static int rewrite_ds_pebs_records(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
+static int save_ds_pebs_reset_values(struct kvm_vcpu *vcpu)
+{
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	struct kvm_pmc *pmc = NULL;
+	struct debug_store *ds = NULL;
+	int srcu_idx, bit, idx, ret;
+
+	ds = kmalloc(sizeof(struct debug_store), GFP_KERNEL);
+	if (!ds)
+		return -ENOMEM;
+
+	ret = -EFAULT;
+	srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+	if (kvm_read_guest_cached(vcpu->kvm, &pmu->ds_area_cache,
+			ds, sizeof(struct debug_store)))
+		goto out;
+
+	for_each_set_bit(bit, (unsigned long *)&pmu->pebs_enable, X86_PMC_IDX_MAX) {
+		pmc = kvm_x86_ops.pmu_ops->pmc_idx_to_pmc(pmu, bit);
+
+		if (pmc) {
+			idx = (pmc->idx < INTEL_PMC_IDX_FIXED) ?
+				pmc->idx : (MAX_PEBS_EVENTS + pmc->idx - INTEL_PMC_IDX_FIXED);
+			pmc->reset_counter = ds->pebs_event_reset[idx];
+		}
+	}
+	ret = 0;
+
+out:
+	srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx);
+	kfree(ds);
+	return ret;
+}
+
 static void intel_pmu_handle_event(struct kvm_vcpu *vcpu)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
-	int ret1, ret2;
+	int ret1, ret2, ret3;
 
 	if (pmu->need_rewrite_pebs_records) {
 		pmu->need_rewrite_pebs_records = false;
@@ -642,11 +678,16 @@ static void intel_pmu_handle_event(struct kvm_vcpu *vcpu)
 		ret2 = rewrite_ds_pebs_interrupt_threshold(vcpu);
 	}
 
+	if (pmu->need_save_reset_counter) {
+		pmu->need_save_reset_counter = false;
+		ret3 = save_ds_pebs_reset_values(vcpu);
+	}
+
 out:
 
-	if (ret1 == -ENOMEM || ret2 == -ENOMEM)
+	if (ret1 == -ENOMEM || ret2 == -ENOMEM || ret3 == -ENOMEM)
 		pr_debug_ratelimited("%s: Fail to emulate guest PEBS due to OOM.", __func__);
-	else if (ret1 == -EFAULT || ret2 == -EFAULT)
+	else if (ret1 == -EFAULT || ret2 == -EFAULT || ret3 == -EFAULT)
 		pr_debug_ratelimited("%s: Fail to emulate guest PEBS due to GPA fault.", __func__);
 }
 
-- 
2.29.2


  parent reply	other threads:[~2021-01-04 13:30 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-04 13:15 [PATCH v3 00/17] KVM: x86/pmu: Add support to enable Guest PEBS via DS Like Xu
2021-01-04 13:15 ` [PATCH v3 01/17] KVM: x86/pmu: Set MSR_IA32_MISC_ENABLE_EMON bit when vPMU is enabled Like Xu
2021-01-04 13:15 ` [PATCH v3 02/17] KVM: x86/pmu: Use IA32_PERF_CAPABILITIES to adjust features visibility Like Xu
2021-01-04 13:15 ` [PATCH v3 03/17] KVM: x86/pmu: Introduce the ctrl_mask value for fixed counter Like Xu
2021-01-13 18:06   ` Peter Zijlstra
2021-01-14  1:58     ` Xu, Like
2021-01-04 13:15 ` [PATCH v3 04/17] perf: x86/ds: Handle guest PEBS overflow PMI and inject it to guest Like Xu
2021-01-13 18:22   ` Peter Zijlstra
2021-01-13 18:27     ` Peter Zijlstra
2021-01-14  3:39     ` Xu, Like
2021-01-15 12:01       ` Peter Zijlstra
2021-01-15 14:30         ` Xu, Like
2021-01-15 14:44           ` Peter Zijlstra
2021-01-15 15:12             ` Xu, Like
2021-01-25  8:26             ` Like Xu
2021-01-25 11:47               ` Peter Zijlstra
2021-02-02  6:31                 ` Xu, Like
2021-01-14 18:55   ` Sean Christopherson
2021-01-15  2:49     ` Xu, Like
2021-01-15 17:42       ` Sean Christopherson
2021-01-22  5:30         ` Like Xu
2021-01-04 13:15 ` [PATCH v3 05/17] KVM: x86/pmu: Reprogram guest PEBS event to emulate guest PEBS counter Like Xu
2021-01-15 11:33   ` Peter Zijlstra
2021-01-15 13:53     ` Xu, Like
2021-01-04 13:15 ` [PATCH v3 06/17] KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS Like Xu
2021-01-05 21:11   ` Sean Christopherson
2021-01-07 12:38     ` Xu, Like
2021-01-15 14:46   ` Peter Zijlstra
2021-01-15 15:29     ` Xu, Like
2021-01-04 13:15 ` [PATCH v3 07/17] KVM: x86/pmu: Add IA32_DS_AREA MSR emulation to manage guest DS buffer Like Xu
2021-01-05 21:16   ` Sean Christopherson
2021-01-08  3:05     ` Xu, Like
2021-01-04 13:15 ` [PATCH v3 08/17] KVM: x86/pmu: Add PEBS_DATA_CFG MSR emulation to support adaptive PEBS Like Xu
2021-01-04 13:15 ` [PATCH v3 09/17] KVM: x86: Set PEBS_UNAVAIL in IA32_MISC_ENABLE when PEBS is enabled Like Xu
2021-01-04 13:15 ` [PATCH v3 10/17] KVM: x86/pmu: Expose CPUIDs feature bits PDCM, DS, DTES64 Like Xu
2021-01-04 13:15 ` [PATCH v3 11/17] KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter Like Xu
2021-01-04 13:15 ` [PATCH v3 12/17] KVM: x86/pmu: Disable guest PEBS when counters are cross-mapped Like Xu
2021-01-04 13:15 ` [PATCH v3 13/17] KVM: x86/pmu: Add hook to emulate pebs for cross-mapped counters Like Xu
2021-01-04 13:15 ` [PATCH v3 14/17] KVM: vmx/pmu: Limit pebs_interrupt_threshold in the guest DS area Like Xu
2021-01-04 13:15 ` [PATCH v3 15/17] KVM: vmx/pmu: Rewrite applicable_counters field in guest PEBS records Like Xu
2021-01-04 13:15 ` Like Xu [this message]
2021-01-04 13:15 ` [PATCH v3 17/17] KVM: x86/pmu: Adjust guest pebs reset values for crpss-mapped counters Like Xu
2021-01-14 19:10 ` [PATCH v3 00/17] KVM: x86/pmu: Add support to enable Guest PEBS via DS Sean Christopherson
2021-01-15  2:02   ` Xu, Like
2021-01-15 17:57     ` Sean Christopherson
2021-01-15 18:27       ` Andi Kleen
2021-01-15 18:51         ` Sean Christopherson
2021-01-15 19:11           ` Andi Kleen
2021-01-22  9:56           ` Peter Zijlstra
2021-01-25  8:08             ` Like Xu
2021-01-25 11:13               ` Peter Zijlstra
2021-01-25 12:07                 ` Xu, Like
2021-01-25 12:18                   ` Peter Zijlstra
2021-01-25 12:53                     ` Xu, Like

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