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authorSean Christopherson <seanjc@google.com>2024-04-05 02:16:14 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2024-04-05 02:42:19 +0200
commit8cb4a9a82b21623dbb4b3051dd30d98356cf95bc (patch)
treec6c5a0ad3f871c21752353ef2430b6bea2e9c095
parentMerge tag 'net-6.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netd... (diff)
downloadlinux-8cb4a9a82b21623dbb4b3051dd30d98356cf95bc.tar.xz
linux-8cb4a9a82b21623dbb4b3051dd30d98356cf95bc.zip
x86/cpufeatures: Add CPUID_LNX_5 to track recently added Linux-defined word
Add CPUID_LNX_5 to track cpufeatures' word 21, and add the appropriate compile-time assert in KVM to prevent direct lookups on the features in CPUID_LNX_5. KVM uses X86_FEATURE_* flags to manage guest CPUID, and so must translate features that are scattered by Linux from the Linux-defined bit to the hardware-defined bit, i.e. should never try to directly access scattered features in guest CPUID. Opportunistically add NR_CPUID_WORDS to enum cpuid_leafs, along with a compile-time assert in KVM's CPUID infrastructure to ensure that future additions update cpuid_leafs along with NCAPINTS. No functional change intended. Fixes: 7f274e609f3d ("x86/cpufeatures: Add new word for scattered features") Cc: Sandipan Das <sandipan.das@amd.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/x86/include/asm/cpufeature.h2
-rw-r--r--arch/x86/kvm/reverse_cpuid.h2
2 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 42157ddcc09d..686e92d2663e 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -33,6 +33,8 @@ enum cpuid_leafs
CPUID_7_EDX,
CPUID_8000_001F_EAX,
CPUID_8000_0021_EAX,
+ CPUID_LNX_5,
+ NR_CPUID_WORDS,
};
#define X86_CAP_FMT_NUM "%d:%d"
diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h
index aadefcaa9561..58ac8d69c94b 100644
--- a/arch/x86/kvm/reverse_cpuid.h
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -102,10 +102,12 @@ static const struct cpuid_reg reverse_cpuid[] = {
*/
static __always_inline void reverse_cpuid_check(unsigned int x86_leaf)
{
+ BUILD_BUG_ON(NR_CPUID_WORDS != NCAPINTS);
BUILD_BUG_ON(x86_leaf == CPUID_LNX_1);
BUILD_BUG_ON(x86_leaf == CPUID_LNX_2);
BUILD_BUG_ON(x86_leaf == CPUID_LNX_3);
BUILD_BUG_ON(x86_leaf == CPUID_LNX_4);
+ BUILD_BUG_ON(x86_leaf == CPUID_LNX_5);
BUILD_BUG_ON(x86_leaf >= ARRAY_SIZE(reverse_cpuid));
BUILD_BUG_ON(reverse_cpuid[x86_leaf].function == 0);
}