On 7/18/2019 4:15 PM, Paolo Bonzini wrote:
On 18/07/19 06:55, Jing Liu wrote:
+ *eax = kvm_arch_get_supported_cpuid(cs->kvm_state, 0x7,
+ count, R_EAX);
This needs to be firstly checked as follows, otherwise some
architectures would fail to compile.
What about hvf and tcg CPUID 07 EAX value?
+ /* Maximum ECX value for sub-leaves */
+ if (kvm_enabled()) {
+ *eax = kvm_arch_get_supported_cpuid(cs->kvm_state, 0x7,
+ count, R_EAX);
+ } else if (hvf_enabled()) {
+ *eax = hvf_get_supported_cpuid(0x7, count, R_EAX);
+ } else {
+ *eax = 0;
+ }
Good question. You need to add a new property, for example
cpuid_level_func7, whose code would be modeled around cpuid_level (and a
field cpuid_min_level_func7 whose code would be modeled around
cpuid_min_level).
Then CPUID[7,0].EAX is set automatically to 0 or 1 depending on whether
BF16 is enabled or not.
Could I ask why don't we directly check BF16 enabling when
cpu_x86_cpuid(env, 7, 0, ...) during kvm_arch_init_vcpu ?
What is the use of the two new properties? Are they used for users
setting parameters when boot up guest, and why we need users setting
func7 level?
I tried to implement the code as follows.
@@ -4293,13 +4313,19 @@ 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;
[...]
+ } else if (count == 1) {
+ *eax = env->features[FEAT_7_1_EAX];
+ *ebx = 0;
+ *ecx = 0;
+ *edx = 0;
[...]
@@ -5075,6 +5101,10 @@ static void x86_cpu_expand_features(X86CPU *cpu,
Error **errp)
x86_cpu_adjust_feat_level(cpu, FEAT_SVM);
x86_cpu_adjust_feat_level(cpu, FEAT_XSAVE);
+ if ((env->features[FEAT_7_1_EAX] & CPUID_7_1_EAX_AVX512_BF16) &&
+ kvm_enabled()) {
+ x86_cpu_adjust_level(cpu, &env->cpuid_min_level_func7, 1);
+ }
/* Intel Processor Trace requires CPUID[0x14] */
if ((env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_INTEL_PT) &&
kvm_enabled() && cpu->intel_pt_auto_level) {
@@ -5098,6 +5128,9 @@ 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;
}
@@ -5869,9 +5902,11 @@ 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),
+ DEFINE_PROP_UINT32("min-level-func7", X86CPU,
env.cpuid_min_level_func7, 0),
[...]
Thanks,
Jing
Paolo
