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From: Giacomo Mazzola <gmazz@amazon.de>
To: <kvm@vger.kernel.org>
Cc: Giacomo Mazzola <gmazz@amazon.de>
Subject: [kvm-unit-tests PATCH v2 3/8] x86: skip PMU init when no PMU is advertised
Date: Tue, 20 Oct 2026 15:25:20 +0000	[thread overview]
Message-ID: <20261020152525.57694-4-gmazz@amazon.de> (raw)
In-Reply-To: <20261020152525.57694-1-gmazz@amazon.de>

Guard pmu_init() behind CPUID checks: Intel's architectural PMU
version (CPUID 0xA EAX[7:0]) and AMD's PERFCTR_CORE feature bit.
Without a PMU, accessing performance counter MSRs triggers #GP.

Signed-off-by: Giacomo Mazzola <gmazz@amazon.de>
---
 lib/x86/setup.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/x86/setup.c b/lib/x86/setup.c
index 09241b33..8c8b6e63 100644
--- a/lib/x86/setup.c
+++ b/lib/x86/setup.c
@@ -416,5 +416,7 @@ void bsp_rest_init(void)
 	bringup_aps();
 	enable_x2apic();
 	smp_init();
-	pmu_init();
+	if (this_cpu_property(X86_PROPERTY_PMU_VERSION) ||
+	    this_cpu_has(X86_FEATURE_PERFCTR_CORE))
+		pmu_init();
 }
-- 
2.47.3


  parent reply	other threads:[~2026-10-20 15:26 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-20 15:25 [kvm-unit-tests PATCH v2 0/8] x86: fixes for running KUT as EFI on non-QEMU KVM hosts Giacomo Mazzola
2026-10-20 15:25 ` [kvm-unit-tests PATCH v2 1/8] x86: efi: use PER_CPU_SIZE for per-CPU stack allocation Giacomo Mazzola
2026-10-20 15:25 ` [kvm-unit-tests PATCH v2 2/8] x86: fix EFI memory allocator to clamp regions to 4 GiB Giacomo Mazzola
2026-10-20 15:25 ` Giacomo Mazzola [this message]
2026-10-20 15:25 ` [kvm-unit-tests PATCH v2 4/8] x86: fix ISR thunk to use absolute indirect jump Giacomo Mazzola
2026-10-20 15:25 ` [kvm-unit-tests PATCH v2 5/8] x86: replace per-AP bringup prints with a single summary line Giacomo Mazzola

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