Add following bits related Speculative Return Stack Overflow (SRSO). Guests can make use of these bits if supported. These bits are reported via CPUID Fn8000_0021_EAX. =================================================================== Bit Feature Description =================================================================== 27 SBPB Indicates support for the Selective Branch Predictor Barrier. 28 IBPB_BRTYPE MSR_PRED_CMD[IBPB] flushes all branch type predictions. 29 SRSO_NO Not vulnerable to SRSO. 30 SRSO_USER_KERNEL_NO Not vulnerable to SRSO at the user-kernel boundary. =================================================================== Link: https://www.amd.com/content/dam/amd/en/documents/corporate/cr/speculative-return-stack-overflow-whitepaper.pdf Link: https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/programmer-references/57238.zip Signed-off-by: Babu Moger <babu.moger@xxxxxxx> --- v3: New patch --- target/i386/cpu.c | 2 +- target/i386/cpu.h | 14 +++++++++++--- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 690efd4085..642e71b636 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -1221,7 +1221,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "sbpb", - "ibpb-brtype", NULL, NULL, NULL, + "ibpb-brtype", "srso-no", "srso-user-kernel-no", NULL, }, .cpuid = { .eax = 0x80000021, .reg = R_EAX, }, .tcg_features = 0, diff --git a/target/i386/cpu.h b/target/i386/cpu.h index e0dea1ba54..792518b62d 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -1015,13 +1015,21 @@ uint64_t x86_cpu_get_supported_feature_word(X86CPU *cpu, FeatureWord w); #define CPUID_8000_0008_EBX_AMD_PSFD (1U << 28) /* Processor ignores nested data breakpoints */ -#define CPUID_8000_0021_EAX_NO_NESTED_DATA_BP (1U << 0) +#define CPUID_8000_0021_EAX_NO_NESTED_DATA_BP (1U << 0) /* LFENCE is always serializing */ #define CPUID_8000_0021_EAX_LFENCE_ALWAYS_SERIALIZING (1U << 2) /* Null Selector Clears Base */ -#define CPUID_8000_0021_EAX_NULL_SEL_CLR_BASE (1U << 6) +#define CPUID_8000_0021_EAX_NULL_SEL_CLR_BASE (1U << 6) /* Automatic IBRS */ -#define CPUID_8000_0021_EAX_AUTO_IBRS (1U << 8) +#define CPUID_8000_0021_EAX_AUTO_IBRS (1U << 8) +/* Selective Branch Predictor Barrier */ +#define CPUID_8000_0021_EAX_SBPB (1U << 27) +/* IBPB includes branch type prediction flushing */ +#define CPUID_8000_0021_EAX_IBPB_BRTYPE (1U << 28) +/* Not vulnerable to Speculative Return Stack Overflow */ +#define CPUID_8000_0021_EAX_SRSO_NO (1U << 29) +/* Not vulnerable to SRSO at the user-kernel boundary */ +#define CPUID_8000_0021_EAX_SRSO_USER_KERNEL_NO (1U << 30) /* Performance Monitoring Version 2 */ #define CPUID_8000_0022_EAX_PERFMON_V2 (1U << 0) -- 2.34.1
