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2c47e7a74f
Previously any PMU overflow interrupt that fired while a VCPU was loaded was recorded as a guest event whether it truly was or not. This resulted in nonsense perf recordings that did not honor perf_event_attr.exclude_guest and recorded guest IPs where it should have recorded host IPs. Rework the sampling logic to only record guest samples for events with exclude_guest = 0. This way any host-only events with exclude_guest set will never see unexpected guest samples. The behaviour of events with exclude_guest = 0 is unchanged. Note that events configured to sample both host and guest may still misattribute a PMI that arrived in the host as a guest event depending on KVM arch and vendor behavior. Signed-off-by: Colton Lewis <coltonlewis@google.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Kan Liang <kan.liang@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lore.kernel.org/r/20241113190156.2145593-6-coltonlewis@google.com
41 lines
872 B
C
41 lines
872 B
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* arm64 callchain support
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*
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* Copyright (C) 2015 ARM Limited
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*/
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#include <linux/perf_event.h>
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#include <linux/stacktrace.h>
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#include <linux/uaccess.h>
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#include <asm/pointer_auth.h>
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static bool callchain_trace(void *data, unsigned long pc)
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{
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struct perf_callchain_entry_ctx *entry = data;
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return perf_callchain_store(entry, pc) == 0;
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}
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void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
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struct pt_regs *regs)
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{
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if (perf_guest_state()) {
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/* We don't support guest os callchain now */
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return;
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}
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arch_stack_walk_user(callchain_trace, entry, regs);
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}
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void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
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struct pt_regs *regs)
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{
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if (perf_guest_state()) {
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/* We don't support guest os callchain now */
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return;
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}
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arch_stack_walk(callchain_trace, entry, current, regs);
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}
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