This is a note to let you know that I've just added the patch titled
x86/virt: Drop unnecessary check on extended CPUID level in cpu_has_svm()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-virt-drop-unnecessary-check-on-extended-cpuid-le.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f35268533a214a3e158edf7aa497c57a8c2c6b07
Author: Sean Christopherson <seanjc@xxxxxxxxxx>
Date: Fri Jul 21 13:18:52 2023 -0700
x86/virt: Drop unnecessary check on extended CPUID level in cpu_has_svm()
[ Upstream commit 5df8ecfe3632d5879d1f154f7aa8de441b5d1c89 ]
Drop the explicit check on the extended CPUID level in cpu_has_svm(), the
kernel's cached CPUID info will leave the entire SVM leaf unset if said
leaf is not supported by hardware. Prior to using cached information,
the check was needed to avoid false positives due to Intel's rather crazy
CPUID behavior of returning the values of the maximum supported leaf if
the specified leaf is unsupported.
Fixes: 682a8108872f ("x86/kvm/svm: Simplify cpu_has_svm()")
Link: https://lore.kernel.org/r/20230721201859.2307736-13-seanjc@xxxxxxxxxx
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h
index 3b12e6b994123..6c2e3ff3cb28f 100644
--- a/arch/x86/include/asm/virtext.h
+++ b/arch/x86/include/asm/virtext.h
@@ -101,12 +101,6 @@ static inline int cpu_has_svm(const char **msg)
return 0;
}
- if (boot_cpu_data.extended_cpuid_level < SVM_CPUID_FUNC) {
- if (msg)
- *msg = "can't execute cpuid_8000000a";
- return 0;
- }
-
if (!boot_cpu_has(X86_FEATURE_SVM)) {
if (msg)
*msg = "svm not available";
