Commit 6ebe4436 authored by Like Xu's avatar Like Xu Committed by Paolo Bonzini
Browse files

KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter 



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: default avatarLike Xu <like.xu@linux.intel.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Message-Id: <20220411101946.20262-10-likexu@tencent.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 79f3e3b5

arch/x86/events/intel/core.c

+1 −1
Original line number Diff line number Diff line
@@ -4024,8 +4024,8 @@ static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr, void *data) 


	if (!x86_pmu.pebs_ept)

		return arr;

	pebs_enable = (*nr)++;



	pebs_enable = (*nr)++;

	arr[pebs_enable] = (struct perf_guest_switch_msr){

		.msr = MSR_IA32_PEBS_ENABLE,

		.host = cpuc->pebs_enabled & ~cpuc->intel_ctrl_guest_mask,

arch/x86/kvm/pmu.c

+2 −0
Original line number Diff line number Diff line
@@ -175,6 +175,8 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type, 
		 * could possibly care here is unsupported and needs changes.

		 */

		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,

arch/x86/kvm/pmu.h

+8 −0
Original line number Diff line number Diff line
@@ -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)
@@ -15,6 +17,12 @@ 
#define VMWARE_BACKDOOR_PMC_REAL_TIME		0x10001

#define VMWARE_BACKDOOR_PMC_APPARENT_TIME	0x10002



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;

	u8 unit_mask;