linux-kernel - [PATCH v2 1/2] perf/x86/intel: Expose EPT-friendly PEBS for SPR and future models

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Date:   Thu, 22 Sep 2022 13:19:28 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Jim Mattson <jmattson@...gle.com>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        linux-perf-users@...r.kernel.org,
        Kan Liang <kan.liang@...ux.intel.com>
Subject: [PATCH v2 1/2] perf/x86/intel: Expose EPT-friendly PEBS for SPR and future models

From: Like Xu <likexu@...cent.com>

According to Intel SDM, the EPT-friendly PEBS is supported by all the
platforms after ICX, ADL and the future platforms with PEBS format 5.

Currently the only in-kernel user of this capability is KVM, which has
very limited support for hybrid core pmu, so ADL and its successors do
not currently expose this capability. When both hybrid core and PEBS
format 5 are present, KVM will decide on its own merits.

Cc: Peter Zijlstra <peterz@...radead.org>
Cc: linux-perf-users@...r.kernel.org
Suggested-by: Kan Liang <kan.liang@...ux.intel.com>
Signed-off-by: Like Xu <likexu@...cent.com>
---
V1 -> V2 Changelog:
- the perf part should be a separate patch; (Kan)
- apply PEBS format 5 to avoid patching every future model; (Kan)

 arch/x86/events/intel/core.c | 1 +
 arch/x86/events/intel/ds.c   | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 2db93498ff71..804540ba4599 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -6288,6 +6288,7 @@ __init int intel_pmu_init(void)
 		x86_pmu.pebs_constraints = intel_spr_pebs_event_constraints;
 		x86_pmu.extra_regs = intel_spr_extra_regs;
 		x86_pmu.limit_period = spr_limit_period;
+		x86_pmu.pebs_ept = 1;
 		x86_pmu.pebs_aliases = NULL;
 		x86_pmu.pebs_prec_dist = true;
 		x86_pmu.pebs_block = true;
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index ba60427caa6d..4e937f685cdc 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2253,8 +2253,10 @@ void __init intel_ds_init(void)
 			x86_pmu.large_pebs_flags |= PERF_SAMPLE_TIME;
 			break;
 
-		case 4:
 		case 5:
+			x86_pmu.pebs_ept = 1;
+			fallthrough;
+		case 4:
 			x86_pmu.drain_pebs = intel_pmu_drain_pebs_icl;
 			x86_pmu.pebs_record_size = sizeof(struct pebs_basic);
 			if (x86_pmu.intel_cap.pebs_baseline) {
-- 
2.37.3