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: c22ac2a ("perf: Enable branch record for software events")
Signed-off-by: Song Liu <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Tested-by: Like Xu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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);