KVM: selftests: Treat AMD Family 17h+ as supporting branch insns retired

When detecting AMD PMU support for encoding "branch instructions retired"
as event 0xc2,0, simply check for Family 17h+ as all Zen CPUs support said
encoding, and AMD will maintain the encoding for backwards compatibility
on future CPUs.

Note, the kernel proper also interprets Family 17h+ as Zen (see the sole
caller of init_amd_zen_common()).

Suggested-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Manali Shukla <manali.shukla@amd.com>
Link: https://lore.kernel.org/r/20240605050835.30491-1-manali.shukla@amd.com
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 5 insertions, 30 deletions

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
index 26b3e7efe5dd..c15513cd74d1 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
@@ -32,8 +32,8 @@ struct __kvm_pmu_event_filter {
 
 /*
  * This event list comprises Intel's known architectural events, plus AMD's
- * "retired branch instructions" for Zen1-Zen3 (and* possibly other AMD CPUs).
- * Note, AMD and Intel use the same encoding for instructions retired.
+ * Branch Instructions Retired for Zen CPUs.  Note, AMD and Intel use the
+ * same encoding for Instructions Retired.
  */
 kvm_static_assert(INTEL_ARCH_INSTRUCTIONS_RETIRED == AMD_ZEN_INSTRUCTIONS_RETIRED);
 
@@ -353,38 +353,13 @@ static bool use_intel_pmu(void)
 	       kvm_pmu_has(X86_PMU_FEATURE_BRANCH_INSNS_RETIRED);
 }
 
-static bool is_zen1(uint32_t family, uint32_t model)
-{
-	return family == 0x17 && model <= 0x0f;
-}
-
-static bool is_zen2(uint32_t family, uint32_t model)
-{
-	return family == 0x17 && model >= 0x30 && model <= 0x3f;
-}
-
-static bool is_zen3(uint32_t family, uint32_t model)
-{
-	return family == 0x19 && model <= 0x0f;
-}
-
 /*
- * Determining AMD support for a PMU event requires consulting the AMD
- * PPR for the CPU or reference material derived therefrom. The AMD
- * test code herein has been verified to work on Zen1, Zen2, and Zen3.
- *
- * Feel free to add more AMD CPUs that are documented to support event
- * select 0xc2 umask 0 as "retired branch instructions."
+ * On AMD, all Family 17h+ CPUs (Zen and its successors) use event encoding
+ * 0xc2,0 for Branch Instructions Retired.
  */
 static bool use_amd_pmu(void)
 {
-	uint32_t family = kvm_cpu_family();
-	uint32_t model = kvm_cpu_model();
-
-	return host_cpu_is_amd &&
-		(is_zen1(family, model) ||
-		 is_zen2(family, model) ||
-		 is_zen3(family, model));
+	return host_cpu_is_amd && kvm_cpu_family() >= 0x17;
 }
 
 /*