Skip to content

Commit

Permalink
x86: Intel AVX512_BF16 feature enabling
Browse files Browse the repository at this point in the history 
Intel CooperLake cpu adds AVX512_BF16 instruction, defining as
CPUID.(EAX=7,ECX=1):EAX[bit 05].

The patch adds a property for setting the subleaf of CPUID leaf 7 in
case that people would like to specify it.

The release spec link as follows,
https://software.intel.com/sites/default/files/managed/c5/15/\
architecture-instruction-set-extensions-programming-reference.pdf

Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
  • Loading branch information
@bonzini
Jing Liu authored and bonzini committed Aug 20, 2019
1 parent de594e4 commit 80db491
Show file tree
Hide file tree
Showing 3 changed files with 47 additions and 2 deletions.
39 changes: 38 additions & 1 deletion target/i386/cpu.c
View file
Expand Up @@ -770,6 +770,7 @@ static void x86_cpu_vendor_words2str(char *dst, uint32_t vendor1,
/* CPUID_7_0_ECX_OSPKE is dynamic */ \
CPUID_7_0_ECX_LA57)
#define TCG_7_0_EDX_FEATURES 0
#define TCG_7_1_EAX_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)
Expand Down Expand Up @@ -1095,6 +1096,25 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
},
.tcg_features = TCG_7_0_EDX_FEATURES,
},
[FEAT_7_1_EAX] = {
.type = CPUID_FEATURE_WORD,
.feat_names = {
NULL, NULL, NULL, NULL,
NULL, "avx512-bf16", 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 = 1,
.reg = R_EAX,
},
.tcg_features = TCG_7_1_EAX_FEATURES,
},
[FEAT_8000_0007_EDX] = {
.type = CPUID_FEATURE_WORD,
.feat_names = {
Expand Down Expand Up @@ -4292,13 +4312,19 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
case 7:
/* Structured Extended Feature Flags Enumeration Leaf */
if (count == 0) {
*eax = 0; /* Maximum ECX value for sub-leaves */
/* Maximum ECX value for sub-leaves */
*eax = env->cpuid_level_func7;
*ebx = env->features[FEAT_7_0_EBX]; /* Feature flags */
*ecx = env->features[FEAT_7_0_ECX]; /* Feature flags */
if ((*ecx & CPUID_7_0_ECX_PKU) && env->cr[4] & CR4_PKE_MASK) {
*ecx |= CPUID_7_0_ECX_OSPKE;
}
*edx = env->features[FEAT_7_0_EDX]; /* Feature flags */
} else if (count == 1) {
*eax = env->features[FEAT_7_1_EAX];
*ebx = 0;
*ecx = 0;
*edx = 0;
} else {
*eax = 0;
*ebx = 0;
Expand Down Expand Up @@ -4948,6 +4974,11 @@ static void x86_cpu_adjust_feat_level(X86CPU *cpu, FeatureWord w)
x86_cpu_adjust_level(cpu, &env->cpuid_min_xlevel2, eax);
break;
}

if (eax == 7) {
x86_cpu_adjust_level(cpu, &env->cpuid_min_level_func7,
fi->cpuid.ecx);
}
}

/* Calculate XSAVE components based on the configured CPU feature flags */
Expand Down Expand Up @@ -5066,6 +5097,7 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
x86_cpu_adjust_feat_level(cpu, FEAT_1_ECX);
x86_cpu_adjust_feat_level(cpu, FEAT_6_EAX);
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_8000_0001_EDX);
x86_cpu_adjust_feat_level(cpu, FEAT_8000_0001_ECX);
x86_cpu_adjust_feat_level(cpu, FEAT_8000_0007_EDX);
Expand Down Expand Up @@ -5097,6 +5129,9 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
}

/* Set cpuid_*level* based on cpuid_min_*level, if not explicitly set */
if (env->cpuid_level_func7 == UINT32_MAX) {
env->cpuid_level_func7 = env->cpuid_min_level_func7;
}
if (env->cpuid_level == UINT32_MAX) {
env->cpuid_level = env->cpuid_min_level;
}
Expand Down Expand Up @@ -5870,6 +5905,8 @@ static Property x86_cpu_properties[] = {
DEFINE_PROP_BOOL("host-phys-bits", X86CPU, host_phys_bits, false),
DEFINE_PROP_UINT8("host-phys-bits-limit", X86CPU, host_phys_bits_limit, 0),
DEFINE_PROP_BOOL("fill-mtrr-mask", X86CPU, fill_mtrr_mask, true),
DEFINE_PROP_UINT32("level-func7", X86CPU, env.cpuid_level_func7,
UINT32_MAX),
DEFINE_PROP_UINT32("level", X86CPU, env.cpuid_level, UINT32_MAX),
DEFINE_PROP_UINT32("xlevel", X86CPU, env.cpuid_xlevel, UINT32_MAX),
DEFINE_PROP_UINT32("xlevel2", X86CPU, env.cpuid_xlevel2, UINT32_MAX),
Expand Down
7 changes: 7 additions & 0 deletions target/i386/cpu.h
View file
Expand Up @@ -479,6 +479,7 @@ typedef enum FeatureWord {
FEAT_7_0_EBX, /* CPUID[EAX=7,ECX=0].EBX */
FEAT_7_0_ECX, /* CPUID[EAX=7,ECX=0].ECX */
FEAT_7_0_EDX, /* CPUID[EAX=7,ECX=0].EDX */
FEAT_7_1_EAX, /* CPUID[EAX=7,ECX=1].EAX */
FEAT_8000_0001_EDX, /* CPUID[8000_0001].EDX */
FEAT_8000_0001_ECX, /* CPUID[8000_0001].ECX */
FEAT_8000_0007_EDX, /* CPUID[8000_0007].EDX */
Expand Down Expand Up @@ -692,6 +693,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
#define CPUID_7_0_EDX_CORE_CAPABILITY (1U << 30) /*Core Capability*/
#define CPUID_7_0_EDX_SPEC_CTRL_SSBD (1U << 31) /* Speculative Store Bypass Disable */

#define CPUID_7_1_EAX_AVX512_BF16 (1U << 5) /* AVX512 BFloat16 Instruction */

#define CPUID_8000_0008_EBX_WBNOINVD (1U << 9) /* Write back and
do not invalidate cache */
#define CPUID_8000_0008_EBX_IBPB (1U << 12) /* Indirect Branch Prediction Barrier */
Expand Down Expand Up @@ -1323,6 +1326,10 @@ typedef struct CPUX86State {
/* Fields after this point are preserved across CPU reset. */

/* processor features (e.g. for CPUID insn) */
/* Minimum cpuid leaf 7 value */
uint32_t cpuid_level_func7;
/* Actual cpuid leaf 7 value */
uint32_t cpuid_min_level_func7;
/* Minimum level/xlevel/xlevel2, based on CPU model + features */
uint32_t cpuid_min_level, cpuid_min_xlevel, cpuid_min_xlevel2;
/* Maximum level/xlevel/xlevel2 value for auto-assignment: */
Expand Down
3 changes: 2 additions & 1 deletion target/i386/kvm.c
View file
Expand Up @@ -1501,6 +1501,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
c = &cpuid_data.entries[cpuid_i++];
}
break;
case 0x7:
case 0x14: {
uint32_t times;

Expand All @@ -1513,7 +1514,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
for (j = 1; j <= times; ++j) {
if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
fprintf(stderr, "cpuid_data is full, no space for "
"cpuid(eax:0x14,ecx:0x%x)\n", j);
"cpuid(eax:0x%x,ecx:0x%x)\n", i, j);
abort();
}
c = &cpuid_data.entries[cpuid_i++];
Expand Down

0 comments on commit 80db491

Please sign in to comment.