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Commit f3fd84a3 authored by Song Liu's avatar Song Liu Committed by Peter Zijlstra
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x86/perf: Fix snapshot_branch_stack warning in VM



When running in VM intel_pmu_snapshot_branch_stack triggers WRMSR warning
like:

 [ ] unchecked MSR access error: WRMSR to 0x3f1 (tried to write 0x0000000000000000) at rIP: 0xffffffff81011a5b (intel_pmu_snapshot_branch_stack+0x3b/0xd0)

This can be triggered with BPF selftests:

  tools/testing/selftests/bpf/test_progs -t get_branch_snapshot

This warning is caused by __intel_pmu_pebs_disable_all() in the VM.
Since it is not necessary to disable PEBS for LBR, remove it from
intel_pmu_snapshot_branch_stack and intel_pmu_snapshot_arch_branch_stack.

Fixes: c22ac2a3 ("perf: Enable branch record for software events")
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: default avatarLike Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20211112054510.2667030-1-songliubraving@fb.com
parent bdc0feee
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