On Fri, Jul 18, 2025, Dapeng Mi wrote: > This patch series fixes KVM PMU kselftests errors encountered on Granite > Rapids (GNR), Sierra Forest (SRF) and Clearwater Forest (CWF). > > GNR and SRF starts to support the timed PEBS. Timed PEBS adds a new > "retired latency" field in basic info group to show the timing info and > the PERF_CAPABILITIES[17] called "PEBS_TIMING_INFO" bit is added > to indicated whether timed PEBS is supported. KVM module doesn't need to > do any specific change to support timed PEBS except a perf change adding > PERF_CAP_PEBS_TIMING_INFO flag into PERF_CAP_PEBS_MASK[1]. The patch 2/5 > adds timed PEBS support in vmx_pmu_caps_test and fix the error as the > PEBS caps field mismatch. > > CWF introduces 5 new architectural events (4 level-1 topdown metrics > events and LBR inserts event). The patch 3/5 adds support for these 5 > arch-events and fixes the error that caused by mismatch between HW real > supported arch-events number with NR_INTEL_ARCH_EVENTS. > > On Intel Atom platforms, the PMU events "Instruction Retired" or > "Branch Instruction Retired" may be overcounted for some certain > instructions, like FAR CALL/JMP, RETF, IRET, VMENTRY/VMEXIT/VMPTRLD > and complex SGX/SMX/CSTATE instructions/flows[2]. > > In details, for the Atom platforms before Sierra Forest (including > Sierra Forest), Both 2 events "Instruction Retired" and > "Branch Instruction Retired" would be overcounted on these certain > instructions, but for Clearwater Forest only "Instruction Retired" event > is overcounted on these instructions. > > As this overcount issue, pmu_counters_test and pmu_event_filter_test > would fail on the precise event count validation for these 2 events on > Atom platforms. > > To work around this Atom platform overcount issue, Patches 4-5/5 looses > the precise count validation separately for pmu_counters_test and > pmu_event_filter_test. > > BTW, this patch series doesn't depend on the mediated vPMU support. > > Changes: > * Add error fix for vmx_pmu_caps_test on GNR/SRF (patch 2/5). > * Opportunistically fix a typo (patch 1/5). > > Tests: > * PMU kselftests (pmu_counters_test/pmu_event_filter_test/ > vmx_pmu_caps_test) passed on Intel SPR/GNR/SRF/CWF platforms. > > History: > * v1: https://lore.kernel.org/all/20250712172522.187414-1-dapeng1.mi@xxxxxxxxxxxxxxx/ > > Ref: > [1] https://lore.kernel.org/all/20250717090302.11316-1-dapeng1.mi@xxxxxxxxxxxxxxx/ > [2] https://edc.intel.com/content/www/us/en/design/products-and-solutions/processors-and-chipsets/sierra-forest/xeon-6700-series-processor-with-e-cores-specification-update/errata-details > > Dapeng Mi (4): > KVM: x86/pmu: Correct typo "_COUTNERS" to "_COUNTERS" > KVM: selftests: Add timing_info bit support in vmx_pmu_caps_test > KVM: Selftests: Validate more arch-events in pmu_counters_test > KVM: selftests: Relax branches event count check for event_filter test > > dongsheng (1): > KVM: selftests: Relax precise event count validation as overcount > issue Overall looks good, I just want to take a more infrastructure-oriented approach for the errata. I'll post a v3 tomorrow. All coding is done and the tests pass, but I want to take a second look with fresh eyes before posting it :-)
