The PEBS-PDIR facility on Ice Lake server is supported on IA31_FIXED0 only.
If the guest configures counter 32 and PEBS is enabled, the PEBS-PDIR
facility is supposed to be used, in which case KVM adjusts attr.precise_ip
to 3 and request host perf to assign the exactly requested counter or fail.
The cpu model check is also required since some platforms may place the
PEBS-PDIR facility in another counter index.
Signed-off-by: Like Xu <like...@linux.intel.com>
---
arch/x86/kvm/pmu.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index c6208234e007..f8aa4724d67b 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -143,6 +143,8 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32
type,
* in the PEBS record is calibrated on the guest side.
*/
attr.precise_ip = 1;
+ if (x86_match_cpu(vmx_icl_pebs_cpu) && pmc->idx == 32)
+ attr.precise_ip = 3;
}
event = perf_event_create_kernel_counter(&attr, -1, current,
--
2.21.3
