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| author | Jim Mattson <jmattson@google.com> | 2024-09-13 19:32:27 +0200 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2024-10-10 10:34:14 +0200 |
| commit | ff898623af2ed564300752bba83a680a1e4fec8d (patch) | |
| tree | 6f71a26ae933378b5eabf2548f862685439ede77 /arch/x86 | |
| parent | Linux 6.12-rc2 (diff) | |
| download | linux-ff898623af2ed564300752bba83a680a1e4fec8d.tar.xz linux-ff898623af2ed564300752bba83a680a1e4fec8d.zip | |
x86/cpufeatures: Define X86_FEATURE_AMD_IBPB_RET
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>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/cpufeatures.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index dd4682857c12..a222a24677d7 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -215,7 +215,7 @@ #define X86_FEATURE_SPEC_STORE_BYPASS_DISABLE ( 7*32+23) /* Disable Speculative Store Bypass. */ #define X86_FEATURE_LS_CFG_SSBD ( 7*32+24) /* AMD SSBD implementation via LS_CFG MSR */ #define X86_FEATURE_IBRS ( 7*32+25) /* "ibrs" Indirect Branch Restricted Speculation */ -#define X86_FEATURE_IBPB ( 7*32+26) /* "ibpb" Indirect Branch Prediction Barrier */ +#define X86_FEATURE_IBPB ( 7*32+26) /* "ibpb" Indirect Branch Prediction Barrier without a guaranteed RSB flush */ #define X86_FEATURE_STIBP ( 7*32+27) /* "stibp" Single Thread Indirect Branch Predictors */ #define X86_FEATURE_ZEN ( 7*32+28) /* Generic flag for all Zen and newer */ #define X86_FEATURE_L1TF_PTEINV ( 7*32+29) /* L1TF workaround PTE inversion */ @@ -348,6 +348,7 @@ #define X86_FEATURE_CPPC (13*32+27) /* "cppc" Collaborative Processor Performance Control */ #define X86_FEATURE_AMD_PSFD (13*32+28) /* Predictive Store Forwarding Disable */ #define X86_FEATURE_BTC_NO (13*32+29) /* Not vulnerable to Branch Type Confusion */ +#define X86_FEATURE_AMD_IBPB_RET (13*32+30) /* IBPB clears return address predictor */ #define X86_FEATURE_BRS (13*32+31) /* "brs" Branch Sampling available */ /* Thermal and Power Management Leaf, CPUID level 0x00000006 (EAX), word 14 */ |