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[v6,11/16] KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter

Message ID 20210511024214.280733-12-like.xu@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86/pmu: Add *basic* support to enable guest PEBS via DS | expand

Commit Message

Like Xu May 11, 2021, 2:42 a.m. UTC
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.xu@linux.intel.com>
---
 arch/x86/kvm/pmu.c | 2 ++
 arch/x86/kvm/pmu.h | 7 +++++++
 2 files changed, 9 insertions(+)
diff mbox series

Patch

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 0f86c1142f17..d3f746877d1b 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -149,6 +149,8 @@  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,
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 67e753edfa22..1af86ae1d3f2 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -4,6 +4,8 @@ 
 
 #include <linux/nospec.h>
 
+#include <asm/cpu_device_id.h>
+
 #define vcpu_to_pmu(vcpu) (&(vcpu)->arch.pmu)
 #define pmu_to_vcpu(pmu)  (container_of((pmu), struct kvm_vcpu, arch.pmu))
 #define pmc_to_pmu(pmc)   (&(pmc)->vcpu->arch.pmu)
@@ -16,6 +18,11 @@ 
 #define VMWARE_BACKDOOR_PMC_APPARENT_TIME	0x10002
 
 #define MAX_FIXED_COUNTERS	3
+static const struct x86_cpu_id vmx_icl_pebs_cpu[] = {
+	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D, NULL),
+	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X, NULL),
+	{}
+};
 
 struct kvm_event_hw_type_mapping {
 	u8 eventsel;