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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 05/17] KVM: x86/pmu: Reprogram guest PEBS event to emulate guest PEBS counter
Date: Mon,  4 Jan 2021 21:15:30 +0800	[thread overview]
Message-ID: <20210104131542.495413-6-like.xu@linux.intel.com> (raw)
In-Reply-To: <20210104131542.495413-1-like.xu@linux.intel.com>

When a guest counter is configured as a PEBS counter through
IA32_PEBS_ENABLE, a guest PEBS event will be reprogrammed by
configuring a non-zero precision level in the perf_event_attr.

The guest PEBS overflow PMI bit would be set in the guest
GLOBAL_STATUS MSR when PEBS facility generates a PEBS
overflow PMI based on guest IA32_DS_AREA MSR.

The attr.precise_ip would be adjusted to a special precision
level when the new PEBS-PDIR feature is supported later which
would affect the host counters scheduling.

The guest PEBS event would not be reused for non-PEBS
guest event even with the same guest counter index.

Originally-by: Andi Kleen <ak@linux.intel.com>
Co-developed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
---
 arch/x86/include/asm/kvm_host.h |  2 ++
 arch/x86/kvm/pmu.c              | 29 +++++++++++++++++++++++++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 94c8bfee4a82..09dacda33fb8 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -449,6 +449,8 @@ struct kvm_pmu {
 	DECLARE_BITMAP(all_valid_pmc_idx, X86_PMC_IDX_MAX);
 	DECLARE_BITMAP(pmc_in_use, X86_PMC_IDX_MAX);
 
+	u64 pebs_enable;
+
 	/*
 	 * The gate to release perf_events not marked in
 	 * pmc_in_use only once in a vcpu time slice.
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 67741d2a0308..2e81c50323e2 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -76,7 +76,12 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event,
 	struct kvm_pmu *pmu = pmc_to_pmu(pmc);
 
 	if (!test_and_set_bit(pmc->idx, pmu->reprogram_pmi)) {
-		__set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
+		if (perf_event->attr.precise_ip) {
+			/* Indicate PEBS overflow PMI to guest. */
+			__set_bit(GLOBAL_STATUS_BUFFER_OVF_BIT,
+				(unsigned long *)&pmu->global_status);
+		} else
+			__set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
 		kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
 
 		/*
@@ -99,6 +104,7 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type,
 				  bool exclude_kernel, bool intr,
 				  bool in_tx, bool in_tx_cp)
 {
+	struct kvm_pmu *pmu = vcpu_to_pmu(pmc->vcpu);
 	struct perf_event *event;
 	struct perf_event_attr attr = {
 		.type = type,
@@ -110,6 +116,7 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type,
 		.exclude_kernel = exclude_kernel,
 		.config = config,
 	};
+	bool pebs = test_bit(pmc->idx, (unsigned long *)&pmu->pebs_enable);
 
 	attr.sample_period = get_sample_period(pmc, pmc->counter);
 
@@ -124,9 +131,23 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type,
 		attr.sample_period = 0;
 		attr.config |= HSW_IN_TX_CHECKPOINTED;
 	}
+	if (pebs) {
+		/*
+		 * The non-zero precision level of guest event makes the ordinary
+		 * guest event becomes a guest PEBS event and triggers the host
+		 * PEBS PMI handler to determine whether the PEBS overflow PMI
+		 * comes from the host counters or the guest.
+		 *
+		 * For most PEBS hardware events, the difference in the software
+		 * precision levels of guest and host PEBS events will not affect
+		 * the accuracy of the PEBS profiling result, because the "event IP"
+		 * in the PEBS record is calibrated on the guest side.
+		 */
+		attr.precise_ip = 1;
+	}
 
 	event = perf_event_create_kernel_counter(&attr, -1, current,
-						 intr ? kvm_perf_overflow_intr :
+						 (intr || pebs) ? kvm_perf_overflow_intr :
 						 kvm_perf_overflow, pmc);
 	if (IS_ERR(event)) {
 		pr_debug_ratelimited("kvm_pmu: event creation failed %ld for pmc->idx = %d\n",
@@ -161,6 +182,10 @@ static bool pmc_resume_counter(struct kvm_pmc *pmc)
 			      get_sample_period(pmc, pmc->counter)))
 		return false;
 
+	if (!test_bit(pmc->idx, (unsigned long *)&pmc_to_pmu(pmc)->pebs_enable) &&
+	    pmc->perf_event->attr.precise_ip)
+		return false;
+
 	/* reuse perf_event to serve as pmc_reprogram_counter() does*/
 	perf_event_enable(pmc->perf_event);
 
-- 
2.29.2


  parent reply	other threads:[~2021-01-04 13:25 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 ` Like Xu [this message]
2021-01-15 11:33   ` [PATCH v3 05/17] KVM: x86/pmu: Reprogram guest PEBS event to emulate guest PEBS counter 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 ` [PATCH v3 16/17] KVM: x86/pmu: Save guest pebs reset values when pebs is configured Like Xu
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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