linux-kernel - [PATCH 1/2] perf/x86/intel/pt: Add a capability and config bit for event tracing

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Date:   Mon, 24 Jan 2022 10:06:50 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        H Peter Anvin <hpa@...or.com>
Subject: [PATCH 1/2] perf/x86/intel/pt: Add a capability and config bit for event tracing

From: Alexander Shishkin <alexander.shishkin@...ux.intel.com>

As of Intel SDM (https://www.intel.com/sdm) version 076, there is a new
Intel PT feature called Event Trace which is enabled config bit 31.

Event Trace exposes details about asynchronous events such as interrupts
and VM-Entry/Exit.

Add a capability and config bit for Event Trace.

Signed-off-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Reviewed-by: Adrian Hunter <adrian.hunter@...el.com>
---
 arch/x86/events/intel/pt.c       | 8 ++++++++
 arch/x86/include/asm/intel_pt.h  | 1 +
 arch/x86/include/asm/msr-index.h | 1 +
 3 files changed, 10 insertions(+)

diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index 7f406c14715f..02727b9b3c8a 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -57,6 +57,7 @@ static struct pt_cap_desc {
 	PT_CAP(mtc,			0, CPUID_EBX, BIT(3)),
 	PT_CAP(ptwrite,			0, CPUID_EBX, BIT(4)),
 	PT_CAP(power_event_trace,	0, CPUID_EBX, BIT(5)),
+	PT_CAP(event_trace,		0, CPUID_EBX, BIT(7)),
 	PT_CAP(topa_output,		0, CPUID_ECX, BIT(0)),
 	PT_CAP(topa_multiple_entries,	0, CPUID_ECX, BIT(1)),
 	PT_CAP(single_range_output,	0, CPUID_ECX, BIT(2)),
@@ -108,6 +109,7 @@ PMU_FORMAT_ATTR(tsc,		"config:10"	);
 PMU_FORMAT_ATTR(noretcomp,	"config:11"	);
 PMU_FORMAT_ATTR(ptw,		"config:12"	);
 PMU_FORMAT_ATTR(branch,		"config:13"	);
+PMU_FORMAT_ATTR(event,		"config:31"	);
 PMU_FORMAT_ATTR(mtc_period,	"config:14-17"	);
 PMU_FORMAT_ATTR(cyc_thresh,	"config:19-22"	);
 PMU_FORMAT_ATTR(psb_period,	"config:24-27"	);
@@ -116,6 +118,7 @@ static struct attribute *pt_formats_attr[] = {
 	&format_attr_pt.attr,
 	&format_attr_cyc.attr,
 	&format_attr_pwr_evt.attr,
+	&format_attr_event.attr,
 	&format_attr_fup_on_ptw.attr,
 	&format_attr_mtc.attr,
 	&format_attr_tsc.attr,
@@ -296,6 +299,7 @@ static int __init pt_pmu_hw_init(void)
 			RTIT_CTL_CYC_PSB	| \
 			RTIT_CTL_MTC		| \
 			RTIT_CTL_PWR_EVT_EN	| \
+			RTIT_CTL_EVENT_EN	| \
 			RTIT_CTL_FUP_ON_PTW	| \
 			RTIT_CTL_PTW_EN)
 
@@ -350,6 +354,10 @@ static bool pt_event_valid(struct perf_event *event)
 	    !intel_pt_validate_hw_cap(PT_CAP_power_event_trace))
 		return false;
 
+	if (config & RTIT_CTL_EVENT_EN &&
+	    !intel_pt_validate_hw_cap(PT_CAP_event_trace))
+		return false;
+
 	if (config & RTIT_CTL_PTW) {
 		if (!intel_pt_validate_hw_cap(PT_CAP_ptwrite))
 			return false;
diff --git a/arch/x86/include/asm/intel_pt.h b/arch/x86/include/asm/intel_pt.h
index ebe8d2ea44fe..d1ef9cb58847 100644
--- a/arch/x86/include/asm/intel_pt.h
+++ b/arch/x86/include/asm/intel_pt.h
@@ -13,6 +13,7 @@ enum pt_capabilities {
 	PT_CAP_mtc,
 	PT_CAP_ptwrite,
 	PT_CAP_power_event_trace,
+	PT_CAP_event_trace,
 	PT_CAP_topa_output,
 	PT_CAP_topa_multiple_entries,
 	PT_CAP_single_range_output,
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 3faf0f97edb1..79b392d893e3 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -205,6 +205,7 @@
 #define RTIT_CTL_DISRETC		BIT(11)
 #define RTIT_CTL_PTW_EN			BIT(12)
 #define RTIT_CTL_BRANCH_EN		BIT(13)
+#define RTIT_CTL_EVENT_EN		BIT(31)
 #define RTIT_CTL_MTC_RANGE_OFFSET	14
 #define RTIT_CTL_MTC_RANGE		(0x0full << RTIT_CTL_MTC_RANGE_OFFSET)
 #define RTIT_CTL_CYC_THRESH_OFFSET	19
-- 
2.25.1