diff options
| author | Kim Phillips <kim.phillips@amd.com> | 2023-01-24 17:33:18 +0100 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2023-01-25 17:16:01 +0100 |
| commit | e7862eda309ecfccc36bb5558d937ed3ace07f3f (patch) | |
| tree | f9421d9634c889fc35fcaed4451f0fc759a68644 /arch/x86/include/asm/msr-index.h | |
| parent | x86/cpu, kvm: Add the SMM_CTL MSR not present feature (diff) | |
| download | linux-e7862eda309ecfccc36bb5558d937ed3ace07f3f.tar.xz linux-e7862eda309ecfccc36bb5558d937ed3ace07f3f.zip | |
x86/cpu: Support AMD Automatic IBRS
The AMD Zen4 core supports a new feature called Automatic IBRS.
It is a "set-and-forget" feature that means that, like Intel's Enhanced IBRS,
h/w manages its IBRS mitigation resources automatically across CPL transitions.
The feature is advertised by CPUID_Fn80000021_EAX bit 8 and is enabled by
setting MSR C000_0080 (EFER) bit 21.
Enable Automatic IBRS by default if the CPU feature is present. It typically
provides greater performance over the incumbent generic retpolines mitigation.
Reuse the SPECTRE_V2_EIBRS spectre_v2_mitigation enum. AMD Automatic IBRS and
Intel Enhanced IBRS have similar enablement. Add NO_EIBRS_PBRSB to
cpu_vuln_whitelist, since AMD Automatic IBRS isn't affected by PBRSB-eIBRS.
The kernel command line option spectre_v2=eibrs is used to select AMD Automatic
IBRS, if available.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-8-kim.phillips@amd.com
Diffstat (limited to 'arch/x86/include/asm/msr-index.h')
| -rw-r--r-- | arch/x86/include/asm/msr-index.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index cb359d69f497..617b29ae5875 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -25,6 +25,7 @@ #define _EFER_SVME 12 /* Enable virtualization */ #define _EFER_LMSLE 13 /* Long Mode Segment Limit Enable */ #define _EFER_FFXSR 14 /* Enable Fast FXSAVE/FXRSTOR */ +#define _EFER_AUTOIBRS 21 /* Enable Automatic IBRS */ #define EFER_SCE (1<<_EFER_SCE) #define EFER_LME (1<<_EFER_LME) @@ -33,6 +34,7 @@ #define EFER_SVME (1<<_EFER_SVME) #define EFER_LMSLE (1<<_EFER_LMSLE) #define EFER_FFXSR (1<<_EFER_FFXSR) +#define EFER_AUTOIBRS (1<<_EFER_AUTOIBRS) /* Intel MSRs. Some also available on other CPUs */ |