[PATCH 1/2] perf/x86/intel: Fix OMR snoop information parsing issues
From: Dapeng Mi
Date: Wed Mar 11 2026 - 04:05:43 EST
When omr_source is 0x2, the omr_snoop (bit[6]) and omr_promoted (bit[7])
fields are combined to represent the snoop information. However, the
omr_promoted field was not left-shifted by 1 bit, resulting in incorrect
snoop information.
Besides, the snoop information parsing is not accurate for some OMR
sources, like the snoop information should be SNOOP_NONE for these memory
access (omr_source >= 7) instead of SNOOP_HIT.
Fix these issues.
Reported-by: Ian Rogers <irogers@xxxxxxxxxx>
Closes: https://lore.kernel.org/all/CAP-5=fW4zLWFw1v38zCzB9-cseNSTTCtup=p2SDxZq7dPayVww@xxxxxxxxxxxxxx/
Fixes: d2bdcde9626c ("perf/x86/intel: Add support for PEBS memory auxiliary info field in DMR")
Signed-off-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
---
arch/x86/events/intel/ds.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 5027afc97b65..7f0d515c07c5 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -345,12 +345,12 @@ static u64 parse_omr_data_source(u8 dse)
if (omr.omr_remote)
val |= REM;
- val |= omr.omr_hitm ? P(SNOOP, HITM) : P(SNOOP, HIT);
-
if (omr.omr_source == 0x2) {
- u8 snoop = omr.omr_snoop | omr.omr_promoted;
+ u8 snoop = omr.omr_snoop | (omr.omr_promoted << 1);
- if (snoop == 0x0)
+ if (omr.omr_hitm)
+ val |= P(SNOOP, HITM);
+ else if (snoop == 0x0)
val |= P(SNOOP, NA);
else if (snoop == 0x1)
val |= P(SNOOP, MISS);
@@ -359,7 +359,10 @@ static u64 parse_omr_data_source(u8 dse)
else if (snoop == 0x3)
val |= P(SNOOP, NONE);
} else if (omr.omr_source > 0x2 && omr.omr_source < 0x7) {
+ val |= omr.omr_hitm ? P(SNOOP, HITM) : P(SNOOP, HIT);
val |= omr.omr_snoop ? P(SNOOPX, FWD) : 0;
+ } else {
+ val |= P(SNOOP, NONE);
}
return val;
base-commit: 73cee0aad1ee2479fde2c9b753a1b66acb7d1b9a
--
2.34.1