x86/cpufeatures: Define X86_FEATURE_AMD_IBPB_RET

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commit ff898623af upstream.

AMD's initial implementation of IBPB did not clear the return address
predictor. Beginning with Zen4, AMD's IBPB *does* clear the return address
predictor. This behavior is enumerated by CPUID.80000008H:EBX.IBPB_RET[30].

Define X86_FEATURE_AMD_IBPB_RET for use in KVM_GET_SUPPORTED_CPUID,
when determining cross-vendor capabilities.

Suggested-by: Venkatesh Srinivas <venkateshs@chromium.org>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Jim Mattson 2024-09-13 10:32:27 -07:00 • committed by Greg Kroah-Hartman

parent 6328b4891b

commit bc114b2a04

1 changed files with 2 additions and 1 deletions

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arch/x86/include/asm/cpufeatures.h

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