Thread (183 messages) 183 messages, 7 authors, 2022-01-31
STALE1620d

[PATCH 5.10 032/167] KVM: x86/pmu: Clear anythread deprecated bit when 0xa leaf is unsupported on the SVM

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-07-26 16:17:57
Also in: lkml
Subsystem: kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

From: Like Xu <redacted>

[ Upstream commit 7234c362ccb3c2228f06f19f93b132de9cfa7ae4 ]

The AMD platform does not support the functions Ah CPUID leaf. The returned
results for this entry should all remain zero just like the native does:

AMD host:
   0x0000000a 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000
(uncanny) AMD guest:
   0x0000000a 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00008000

Fixes: cadbaa039b99 ("perf/x86/intel: Make anythread filter support conditional")
Signed-off-by: Like Xu <redacted>
Message-Id: [off-list ref]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/cpuid.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 7a3fbf3b796e..41b0dc37720e 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -684,7 +684,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 
 		edx.split.num_counters_fixed = min(cap.num_counters_fixed, MAX_FIXED_COUNTERS);
 		edx.split.bit_width_fixed = cap.bit_width_fixed;
-		edx.split.anythread_deprecated = 1;
+		if (cap.version)
+			edx.split.anythread_deprecated = 1;
 		edx.split.reserved1 = 0;
 		edx.split.reserved2 = 0;
 
-- 
2.30.2


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