linux-kernel - [PATCH 4/6] perf amd ibs: Make Fetch status bits dependent on PhyAddrValid for newer platforms

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Message-ID: <20260119024328.897-5-ravi.bangoria@amd.com>
Date: Mon, 19 Jan 2026 02:43:25 +0000
From: Ravi Bangoria <ravi.bangoria@....com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>
CC: Ravi Bangoria <ravi.bangoria@....com>, Arnaldo Carvalho de Melo
	<acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, Ian Rogers
	<irogers@...gle.com>, Dapeng Mi <dapeng1.mi@...ux.intel.com>, James Clark
	<james.clark@...aro.org>, <x86@...nel.org>,
	<linux-perf-users@...r.kernel.org>, <linux-kernel@...r.kernel.org>, "Manali
 Shukla" <manali.shukla@....com>, Santosh Shukla <santosh.shukla@....com>,
	Ananth Narayan <ananth.narayan@....com>, Sandipan Das <sandipan.das@....com>
Subject: [PATCH 4/6] perf amd ibs: Make Fetch status bits dependent on PhyAddrValid for newer platforms

On future CPU SOCs, all IBS_FETCH_CTL status fields are valid only if
IBS_FETCH_CTL[IbsPhyAddrValid] is set. Ditto for IBS_FETCH_CTL_EXT. Add
these checks while decoding IBS MSRs.

Unfortunately, there is no CPUID bit to indicate the change. Fallback
to Family/Model check.

Signed-off-by: Ravi Bangoria <ravi.bangoria@....com>
---
 tools/perf/util/amd-sample-raw.c | 42 ++++++++++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/amd-sample-raw.c b/tools/perf/util/amd-sample-raw.c
index 385308c55f34..ae005eb0363d 100644
--- a/tools/perf/util/amd-sample-raw.c
+++ b/tools/perf/util/amd-sample-raw.c
@@ -22,6 +22,29 @@ static bool zen4_ibs_extensions;
 static bool ldlat_cap;
 static bool dtlb_pgsize_cap;
 
+/*
+ * Status fields of IBS_FETCH_CTL and IBS_FETCH_CTL_EXT are valid only if
+ * IBS_FETCH_CTL[PhyAddrValid] is set.
+ */
+static int fetch_ctl_depends_on_phy_addr_valid(void)
+{
+	static int depends = -1; /* -1: Don't know, 1: Yes, 0: No */
+
+	if (depends != -1)
+		return depends;
+
+	depends = 0;
+	if (cpu_family > 0x1a ||
+	    (cpu_family == 0x1a && (
+	     (cpu_model >= 0x50 && cpu_model <= 0x5f) ||
+	     (cpu_model >= 0x80 && cpu_model <= 0xaf) ||
+	     (cpu_model >= 0xc0 && cpu_model <= 0xcf)))) {
+		depends = 1;
+	}
+
+	return depends;
+}
+
 static void pr_ibs_fetch_ctl(union ibs_fetch_ctl reg)
 {
 	const char * const ic_miss_strs[] = {
@@ -43,6 +66,18 @@ static void pr_ibs_fetch_ctl(union ibs_fetch_ctl reg)
 	const char *ic_miss_str = NULL;
 	const char *l1tlb_pgsz_str = NULL;
 	char l3_miss_str[sizeof(" L3MissOnly _ FetchOcMiss _ FetchL3Miss _")] = "";
+	char l3_miss_only_str[sizeof(" L3MissOnly _")] = "";
+
+	if (fetch_ctl_depends_on_phy_addr_valid() && !reg.phy_addr_valid) {
+		snprintf(l3_miss_only_str, sizeof(l3_miss_only_str),
+			 " L3MissOnly %d", reg.l3_miss_only);
+
+		printf("ibs_fetch_ctl:\t%016llx MaxCnt %7d Cnt %7d En %d Val %d Comp %d "
+		       "PhyAddrValid 0 RandEn %d%s\n", reg.val, reg.fetch_maxcnt << 4,
+		       reg.fetch_cnt << 4, reg.fetch_en, reg.fetch_val, reg.fetch_comp,
+		       reg.rand_en, l3_miss_only_str);
+		return;
+	}
 
 	if (cpu_family == 0x19 && cpu_model < 0x10) {
 		/*
@@ -72,8 +107,11 @@ static void pr_ibs_fetch_ctl(union ibs_fetch_ctl reg)
 		l3_miss_str);
 }
 
-static void pr_ic_ibs_extd_ctl(union ic_ibs_extd_ctl reg)
+static void pr_ic_ibs_extd_ctl(union ibs_fetch_ctl fetch_ctl, union ic_ibs_extd_ctl reg)
 {
+	if (fetch_ctl_depends_on_phy_addr_valid() && !fetch_ctl.phy_addr_valid)
+		return;
+
 	printf("ic_ibs_ext_ctl:\t%016llx IbsItlbRefillLat %3d\n", reg.val, reg.itlb_refill_lat);
 }
 
@@ -285,7 +323,7 @@ static void amd_dump_ibs_fetch(struct perf_sample *sample)
 	printf("IbsFetchLinAd:\t%016llx\n", *addr++);
 	if (fetch_ctl->phy_addr_valid)
 		printf("IbsFetchPhysAd:\t%016llx\n", *addr);
-	pr_ic_ibs_extd_ctl(*extd_ctl);
+	pr_ic_ibs_extd_ctl(*fetch_ctl, *extd_ctl);
 }
 
 /*
-- 
2.43.0