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target/i386: Add support for MCDT_NO in CPUID enumeration

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CPUID.(EAX=7,ECX=2):EDX[bit 5] enumerates MCDT_NO. Processors enumerate
this bit as 1 do not exhibit MXCSR Configuration Dependent Timing (MCDT)
behavior and do not need to be mitigated to avoid data-dependent behavior
for certain instructions.

Since MCDT_NO is in a new sub-leaf, add a new CPUID feature word
FEAT_7_2_EDX. Also update cpuid_level_func7 by FEAT_7_2_EDX.

Signed-off-by: Tao Su <tao1.su@linux.intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-ID: <20230706054949.66556-3-tao1.su@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Tao Su 2023-07-06 13:49:45 +08:00 committed by Paolo Bonzini
parent 8731336e90
commit 9dd8b71091
2 changed files with 30 additions and 0 deletions
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26
target/i386/cpu.c
View File

@ -739,6 +739,7 @@ void x86_cpu_vendor_words2str(char *dst, uint32_t vendor1,
#define TCG_7_1_EAX_FEATURES (CPUID_7_1_EAX_FZRM | CPUID_7_1_EAX_FSRS | \
CPUID_7_1_EAX_FSRC)
#define TCG_7_1_EDX_FEATURES 0
#define TCG_7_2_EDX_FEATURES 0
#define TCG_APM_FEATURES 0
#define TCG_6_EAX_FEATURES CPUID_6_EAX_ARAT
#define TCG_XSAVE_FEATURES (CPUID_XSAVE_XSAVEOPT | CPUID_XSAVE_XGETBV1)
@ -993,6 +994,25 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
},
.tcg_features = TCG_7_1_EDX_FEATURES,
},
[FEAT_7_2_EDX] = {
.type = CPUID_FEATURE_WORD,
.feat_names = {
NULL, NULL, NULL, NULL,
NULL, "mcdt-no", NULL, NULL,
NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL,
},
.cpuid = {
.eax = 7,
.needs_ecx = true, .ecx = 2,
.reg = R_EDX,
},
.tcg_features = TCG_7_2_EDX_FEATURES,
},
[FEAT_8000_0007_EDX] = {
.type = CPUID_FEATURE_WORD,
.feat_names = {
@ -6017,6 +6037,11 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
*edx = env->features[FEAT_7_1_EDX];
*ebx = 0;
*ecx = 0;
} else if (count == 2) {
*edx = env->features[FEAT_7_2_EDX];
*eax = 0;
*ebx = 0;
*ecx = 0;
} else {
*eax = 0;
*ebx = 0;
@ -6881,6 +6906,7 @@ void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
x86_cpu_adjust_feat_level(cpu, FEAT_7_0_ECX);
x86_cpu_adjust_feat_level(cpu, FEAT_7_1_EAX);
x86_cpu_adjust_feat_level(cpu, FEAT_7_1_EDX);
x86_cpu_adjust_feat_level(cpu, FEAT_7_2_EDX);
x86_cpu_adjust_feat_level(cpu, FEAT_8000_0001_EDX);
x86_cpu_adjust_feat_level(cpu, FEAT_8000_0001_ECX);
x86_cpu_adjust_feat_level(cpu, FEAT_8000_0007_EDX);

4
target/i386/cpu.h
View File

@ -628,6 +628,7 @@ typedef enum FeatureWord {
FEAT_XSAVE_XSS_LO, /* CPUID[EAX=0xd,ECX=1].ECX */
FEAT_XSAVE_XSS_HI, /* CPUID[EAX=0xd,ECX=1].EDX */
FEAT_7_1_EDX, /* CPUID[EAX=7,ECX=1].EDX */
FEAT_7_2_EDX, /* CPUID[EAX=7,ECX=2].EDX */
FEATURE_WORDS,
} FeatureWord;
@ -932,6 +933,9 @@ uint64_t x86_cpu_get_supported_feature_word(FeatureWord w,
/* PREFETCHIT0/1 Instructions */
#define CPUID_7_1_EDX_PREFETCHITI (1U << 14)
/* Do not exhibit MXCSR Configuration Dependent Timing (MCDT) behavior */
#define CPUID_7_2_EDX_MCDT_NO (1U << 5)
/* XFD Extend Feature Disabled */
#define CPUID_D_1_EAX_XFD (1U << 4)