perf/x86/intel: Add EPT-Friendly PEBS for Ice Lake Server

Add support for EPT-Friendly PEBS, a new CPU feature that enlightens PEBS
to translate guest linear address through EPT, and facilitates handling
VM-Exits that occur when accessing PEBS records.  More information can
be found in the December 2021 release of Intel's SDM, Volume 3,
18.9.5 "EPT-Friendly PEBS". This new hardware facility makes sure the
guest PEBS records will not be lost, which is available on Intel Ice Lake
Server platforms (and later).

KVM will check this field through perf_get_x86_pmu_capability() instead
of hard coding the CPU models in the KVM code. If it is supported, the
guest PEBS capability will be exposed to the guest. Guest PEBS can be
enabled when and only when "EPT-Friendly PEBS" is supported and
EPT is enabled.

Cc: linux-perf-users@vger.kernel.org
Signed-off-by: Like Xu <likexu@tencent.com>
Message-Id: <20220411101946.20262-2-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/events/core.c

@@ -3002,5 +3002,6 @@ void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap)
 	cap->bit_width_fixed	= x86_pmu.cntval_bits;
 	cap->events_mask	= (unsigned int)x86_pmu.events_maskl;
 	cap->events_mask_len	= x86_pmu.events_mask_len;
+	cap->pebs_ept		= x86_pmu.pebs_ept;
 }
 EXPORT_SYMBOL_GPL(perf_get_x86_pmu_capability);

arch/x86/events/intel/core.c

@@ -6138,6 +6138,7 @@ __init int intel_pmu_init(void)
 
 	case INTEL_FAM6_ICELAKE_X:
 	case INTEL_FAM6_ICELAKE_D:
+		x86_pmu.pebs_ept = 1;
 		pmem = true;
 		fallthrough;
 	case INTEL_FAM6_ICELAKE_L:

arch/x86/events/perf_event.h

@@ -818,7 +818,8 @@ struct x86_pmu {
 			pebs_prec_dist		:1,
 			pebs_no_tlb		:1,
 			pebs_no_isolation	:1,
-			pebs_block		:1;
+			pebs_block		:1,
+			pebs_ept		:1;
 	int		pebs_record_size;
 	int		pebs_buffer_size;
 	int		max_pebs_events;

arch/x86/include/asm/perf_event.h

@@ -206,6 +206,7 @@ struct x86_pmu_capability {
 	int		bit_width_fixed;
 	unsigned int	events_mask;
 	int		events_mask_len;
+	unsigned int	pebs_ept	:1;
 };
 
 /*