[PATCH v3 3/9] perf/x86/lbr: Skip checking for the existence of LBR_TOS for Arch LBR

Like Xu
2021-03-03T18:11:46Z

The Architecture LBR does not have MSR_LBR_TOS (0x000001c9). KVM will
generate #GP for this MSR access, thereby preventing the initialization
of the guest LBR.

Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: 47125db27e47 ("perf/x86/intel/lbr: Support Architectural LBR")
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
---
arch/x86/events/intel/core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index a32acc7733a7..3cf065185fb0 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -5569,7 +5569,8 @@ __init int intel_pmu_init(void)
* Check all LBT MSR here.
* Disable LBR access if any LBR MSRs can not be accessed.
*/
- if (x86_pmu.lbr_nr && !check_msr(x86_pmu.lbr_tos, 0x3UL))
+ if (x86_pmu.lbr_nr && !boot_cpu_has(X86_FEATURE_ARCH_LBR) &&
+ !check_msr(x86_pmu.lbr_tos, 0x3UL))
x86_pmu.lbr_nr = 0;
for (i = 0; i < x86_pmu.lbr_nr; i++) {
if (!(check_msr(x86_pmu.lbr_from + i, 0xffffUL) &&
--
2.29.2