From: "tip-bot2 for Sandipan Das" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Vasant Hegde <vasant.hegde@amd.com>,
Sandipan Das <sandipan.das@amd.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: perf/core] kvm: x86/cpuid: Fix CPUID leaf 0xA
Date: Wed, 04 May 2022 09:23:19 -0000 [thread overview]
Message-ID: <165165619987.4207.6901845175738337241.tip-bot2@tip-bot2> (raw)
In-Reply-To: =?utf-8?q?=3C54bc7fe4cadf6bdef823bab1fba43d4891d2e1a9=2E16505?= =?utf-8?q?15382=2Egit=2Esandipan=2Edas=40amd=2Ecom=3E?=
The following commit has been merged into the perf/core branch of tip:
Commit-ID: 202c3484768bce3f077efbbcc1eaa9cac8010093
Gitweb: https://git.kernel.org/tip/202c3484768bce3f077efbbcc1eaa9cac8010093
Author: Sandipan Das <sandipan.das@amd.com>
AuthorDate: Thu, 21 Apr 2022 11:16:59 +05:30
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 04 May 2022 11:18:27 +02:00
kvm: x86/cpuid: Fix CPUID leaf 0xA
On some x86 processors, CPUID leaf 0xA provides information
on Architectural Performance Monitoring features. It
advertises a PMU version which Qemu uses to determine the
availability of additional MSRs to manage the PMCs.
Upon receiving a KVM_GET_SUPPORTED_CPUID ioctl request for
the same, the kernel constructs return values based on the
x86_pmu_capability irrespective of the vendor.
This leaf and the additional MSRs are not supported on AMD
processors. If PerfMonV2 is detected, the PMU version is
set to 2 and guest startup breaks because of an attempt to
access a non-existent MSR. Return zeros to avoid this.
Fixes: a6c06ed1a60a ("KVM: Expose the architectural performance monitoring CPUID leaf")
Reported-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/54bc7fe4cadf6bdef823bab1fba43d4891d2e1a9.1650515382.git.sandipan.das@amd.com
---
arch/x86/kvm/cpuid.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index b24ca7f..ae1d963 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -887,6 +887,12 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
union cpuid10_eax eax;
union cpuid10_edx edx;
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
+ boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
+ entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
+ break;
+ }
+
perf_get_x86_pmu_capability(&cap);
/*
next reply other threads:[~2022-05-04 9:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-04 9:23 tip-bot2 for Sandipan Das [this message]
-- strict thread matches above, loose matches on Subject: below --
2022-04-29 20:28 [tip: perf/core] kvm: x86/cpuid: Fix CPUID leaf 0xA tip-bot2 for Sandipan Das
2022-05-09 17:24 ` Borislav Petkov
2022-05-10 4:59 ` Sandipan Das
2022-05-10 9:35 ` Peter Zijlstra
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