[PATCH v3 1/5] KVM: x86/pmu: Add pebs_vmx support for ATOM_TREMONT

From: Like Xu
Date: Wed May 12 2021 - 04:45:57 EST


The ATOM_TREMONT platform also supports the EPT-Friendly PEBS capability
and we can also safely enable guest PEBS. Per Intel SDM, the PDIR counter
on non-Ice Lake platforms is always GP counter 1;

Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Andi Kleen <andi.kleen@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Signed-off-by: Like Xu <like.xu@xxxxxxxxxxxxxxx>
---
arch/x86/events/intel/core.c | 1 +
arch/x86/kvm/pmu.c | 5 ++---
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index e7bbd9aab175..4404987bbc57 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -5826,6 +5826,7 @@ __init int intel_pmu_init(void)
case INTEL_FAM6_ATOM_TREMONT_D:
case INTEL_FAM6_ATOM_TREMONT:
case INTEL_FAM6_ATOM_TREMONT_L:
+ x86_pmu.pebs_vmx = 1;
x86_pmu.late_ack = true;
memcpy(hw_cache_event_ids, glp_hw_cache_event_ids,
sizeof(hw_cache_event_ids));
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 4798bf991b60..8c700a7930c4 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -151,9 +151,8 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type,
* the accuracy of the PEBS profiling result, because the "event IP"
* 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;
+ attr.precise_ip = x86_match_cpu(vmx_icl_pebs_cpu) ?
+ ((pmc->idx == 32) ? 3 : 1) : ((pmc->idx == 1) ? 3 : 1);
}

event = perf_event_create_kernel_counter(&attr, -1, current,
--
2.31.1