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authorSong Liu <songliubraving@fb.com>2021-11-11 21:45:10 -0800
committerPeter Zijlstra <peterz@infradead.org>2021-11-17 14:48:43 +0100
commitf3fd84a3b7754b60df67ebfe64e1d90623895111 (patch)
tree80bfb788ff8a764e405ce3dc4f553a314d99f95d /arch/x86/events
parentbdc0feee05174418dec1fa68de2af19e1750b99f (diff)
downloadlinux-f3fd84a3b7754b60df67ebfe64e1d90623895111.tar.bz2
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: c22ac2a3d4bd ("perf: Enable branch record for software events") Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Like Xu <likexu@tencent.com> Link: https://lore.kernel.org/r/20211112054510.2667030-1-songliubraving@fb.com
Diffstat (limited to 'arch/x86/events')
-rw-r--r--arch/x86/events/intel/core.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 42cf01ecdd13..ec6444f2c9dc 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2211,7 +2211,6 @@ intel_pmu_snapshot_branch_stack(struct perf_branch_entry *entries, unsigned int
/* must not have branches... */
local_irq_save(flags);
__intel_pmu_disable_all(false); /* we don't care about BTS */
- __intel_pmu_pebs_disable_all();
__intel_pmu_lbr_disable();
/* ... until here */
return __intel_pmu_snapshot_branch_stack(entries, cnt, flags);
@@ -2225,7 +2224,6 @@ intel_pmu_snapshot_arch_branch_stack(struct perf_branch_entry *entries, unsigned
/* must not have branches... */
local_irq_save(flags);
__intel_pmu_disable_all(false); /* we don't care about BTS */
- __intel_pmu_pebs_disable_all();
__intel_pmu_arch_lbr_disable();
/* ... until here */
return __intel_pmu_snapshot_branch_stack(entries, cnt, flags);