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| author | Borislav Petkov (AMD) <bp@alien8.de> | 2023-06-29 17:43:40 +0200 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2023-07-27 11:07:19 +0200 |
| commit | 1b5277c0ea0b247393a9c426769fde18cff5e2f6 (patch) | |
| tree | a7b68ae056148d5304ca880ec781d80bdf41595c /arch/x86/kernel/cpu/amd.c | |
| parent | 79113e4060aba744787a81edb9014f2865193854 (diff) | |
| download | linux-1b5277c0ea0b247393a9c426769fde18cff5e2f6.tar.gz linux-1b5277c0ea0b247393a9c426769fde18cff5e2f6.tar.bz2 linux-1b5277c0ea0b247393a9c426769fde18cff5e2f6.zip | |
x86/srso: Add SRSO_NO support
Add support for the CPUID flag which denotes that the CPU is not
affected by SRSO.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Diffstat (limited to 'arch/x86/kernel/cpu/amd.c')
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 169cb255c483..834f310b2f1a 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -1240,12 +1240,12 @@ bool cpu_has_ibpb_brtype_microcode(void) { u8 fam = boot_cpu_data.x86; - if (fam == 0x17) { - /* Zen1/2 IBPB flushes branch type predictions too. */ + /* Zen1/2 IBPB flushes branch type predictions too. */ + if (fam == 0x17) return boot_cpu_has(X86_FEATURE_AMD_IBPB); - } else if (fam == 0x19) { + /* Poke the MSR bit on Zen3/4 to check its presence. */ + else if (fam == 0x19) + return !wrmsrl_safe(MSR_IA32_PRED_CMD, PRED_CMD_SBPB); + else return false; - } - - return false; } |