From: Zhu Lingshan <lingshan.zhu@intel.com>
To: peterz@infradead.org, pbonzini@redhat.com
Cc: bp@alien8.de, seanjc@google.com, vkuznets@redhat.com,
wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org,
kan.liang@linux.intel.com, ak@linux.intel.com,
wei.w.wang@intel.com, eranian@google.com,
liuxiangdong5@huawei.com, linux-kernel@vger.kernel.org,
x86@kernel.org, kvm@vger.kernel.org, like.xu.linux@gmail.com,
boris.ostrvsky@oracle.com, Like Xu <like.xu@linux.intel.com>,
Zhu Lingshan <lingshan.zhu@intel.com>
Subject: [PATCH V9 09/18] KVM: x86/pmu: Reprogram PEBS event to emulate guest PEBS counter
Date: Thu, 22 Jul 2021 13:41:50 +0800 [thread overview]
Message-ID: <20210722054159.4459-10-lingshan.zhu@intel.com> (raw)
In-Reply-To: <20210722054159.4459-1-lingshan.zhu@intel.com>
From: Like Xu <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.
Even with the same counter index and the same event code and
mask, guest PEBS events will not be reused for non-PEBS events.
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>
Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
arch/x86/kvm/pmu.c | 42 ++++++++++++++++++++++++++++++++++++++----
1 file changed, 38 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 2dcbd1b30004..d76b0a5d80d7 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -74,11 +74,21 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event,
{
struct kvm_pmc *pmc = perf_event->overflow_handler_context;
struct kvm_pmu *pmu = pmc_to_pmu(pmc);
+ bool skip_pmi = false;
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. */
+ skip_pmi = __test_and_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);
+ if (skip_pmi)
+ return;
+
/*
* Inject PMI. If vcpu was in a guest mode during NMI PMI
* can be ejected on a guest mode re-entry. Otherwise we can't
@@ -99,6 +109,7 @@ 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 +121,8 @@ 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);
+ perf_overflow_handler_t ovf = kvm_perf_overflow;
attr.sample_period = get_sample_period(pmc, pmc->counter);
@@ -124,10 +137,27 @@ 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.
+ *
+ * On Icelake everything is fine. Other hardware (GLC+, TNT+) that
+ * could possibly care here is unsupported and needs changes.
+ */
+ attr.precise_ip = 1;
+ }
+ if (pebs || intr)
+ ovf = kvm_perf_overflow_intr;
- event = perf_event_create_kernel_counter(&attr, -1, current,
- intr ? kvm_perf_overflow_intr :
- kvm_perf_overflow, pmc);
+ event = perf_event_create_kernel_counter(&attr, -1, current, ovf, pmc);
if (IS_ERR(event)) {
pr_debug_ratelimited("kvm_pmu: event creation failed %ld for pmc->idx = %d\n",
PTR_ERR(event), pmc->idx);
@@ -161,6 +191,10 @@ 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);
--
2.27.0
next prev parent reply other threads:[~2021-07-22 5:43 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-22 5:41 [PATCH V9 00/18] KVM: x86/pmu: Add *basic* support to enable guest PEBS via DS Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 01/18] perf/core: Use static_call to optimize perf_guest_info_callbacks Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 02/18] perf/x86/intel: Add EPT-Friendly PEBS for Ice Lake Server Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 03/18] perf/x86/intel: Handle guest PEBS overflow PMI for KVM guest Zhu Lingshan
2021-08-05 1:15 ` Liuxiangdong
2021-08-06 12:23 ` Zhu, Lingshan
2021-07-22 5:41 ` [PATCH V9 04/18] perf/x86/core: Pass "struct kvm_pmu *" to determine the guest values Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 05/18] KVM: x86/pmu: Set MSR_IA32_MISC_ENABLE_EMON bit when vPMU is enabled Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 06/18] KVM: x86/pmu: Introduce the ctrl_mask value for fixed counter Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 07/18] x86/perf/core: Add pebs_capable to store valid PEBS_COUNTER_MASK value Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 08/18] KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS Zhu Lingshan
2021-07-22 5:41 ` Zhu Lingshan [this message]
2021-07-22 5:41 ` [PATCH V9 10/18] KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 11/18] KVM: x86/pmu: Add IA32_DS_AREA MSR emulation to support guest DS Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 12/18] KVM: x86/pmu: Add PEBS_DATA_CFG MSR emulation to support adaptive PEBS Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 13/18] KVM: x86: Set PEBS_UNAVAIL in IA32_MISC_ENABLE when PEBS is enabled Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 14/18] KVM: x86/pmu: Move pmc_speculative_in_use() to arch/x86/kvm/pmu.h Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 15/18] KVM: x86/pmu: Disable guest PEBS temporarily in two rare situations Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 16/18] KVM: x86/pmu: Add kvm_pmu_cap to optimize perf_get_x86_pmu_capability Zhu Lingshan
2021-07-30 9:36 ` Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 17/18] KVM: x86/cpuid: Refactor host/guest CPU model consistency check Zhu Lingshan
2021-07-22 5:41 ` [PATCH V9 18/18] KVM: x86/pmu: Expose CPUIDs feature bits PDCM, DS, DTES64 Zhu Lingshan
2021-07-28 15:45 ` [PATCH V9 00/18] KVM: x86/pmu: Add *basic* support to enable guest PEBS via DS Peter Zijlstra
2021-07-28 16:40 ` Like Xu
2021-08-04 3:03 ` Zhu, Lingshan
2021-08-12 13:20 ` [PING][PATCH " Like Xu
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