perf/x86/intel/ds: Fix counter backwards of non-precise events counters-snapshotting
The counter backwards may be observed in the PMI handler when counters-snapshotting some non-precise events in the freq mode. For the non-precise events, it's possible the counters-snapshotting records a positive value for an overflowed PEBS event. Then the HW auto-reload mechanism reset the counter to 0 immediately. Because the pebs_event_reset is cleared in the freq mode, which doesn't set the PERF_X86_EVENT_AUTO_RELOAD. In the PMI handler, 0 will be read rather than the positive value recorded in the counters-snapshotting record. The counters-snapshotting case has to be specially handled. Since the event value has been updated when processing the counters-snapshotting record, only needs to set the new period for the counter via x86_pmu_set_period(). Fixes: e02e9b03 ("perf/x86/intel: Support PEBS counters snapshotting") Signed-off-by:Kan Liang <kan.liang@linux.intel.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20250424134718.311934-6-kan.liang@linux.intel.com
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