x86/cpufeatures: Add CPUID_LNX_5 to track recently added Linux-defined word

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commit 8cb4a9a82b upstream.

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: 7f274e609f ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Sean Christopherson 2024-04-04 17:16:14 -07:00 • committed by Greg Kroah-Hartman

parent b9906101f8

commit 4d47169ab6

2 changed files with 4 additions and 0 deletions

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arch/x86/include/asm/cpufeature.h

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2

arch/x86/kvm/reverse_cpuid.h

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