On Tue, Oct 29, 2024 at 09:25:53AM +0100, Paolo Bonzini wrote:
> On 10/28/24 03:45, Tao Su wrote:
> > @@ -6835,6 +6850,26 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
> > uint32_t count,
> > }
> > break;
> > }
> > + case 0x24: {
> > + *eax = 0;
> > + *ebx = 0;
> > + *ecx = 0;
> > + *edx = 0;
> > + if (!(env->features[FEAT_7_1_EDX] & CPUID_7_1_EDX_AVX10)) {
> > + break;
> > + }
> > +
> > + if (count == 0) {
> > + uint8_t v = kvm_arch_get_supported_cpuid(cs->kvm_state, 0x24,
> > + 0, R_EBX);
> > + if (env->avx10_version && env->avx10_version < v) {
> > + v = env->avx10_version;
> > + }
> > +
> > + *ebx = env->features[FEAT_24_0_EBX] | v;
> > + }
> > + break;
> > + }
> > case 0x40000000:
> > /*
> > * CPUID code in kvm_arch_init_vcpu() ignores stuff
>
> This check should be done elsewhere (called by x86_cpu_realizefn());
> cpu_x86_cpuid() should only report the value:
>
> if ((env->features[FEAT_7_1_EDX] & CPUID_7_1_EDX_AVX10) && count ==
> 0) {
> *ebx = env->features[FEAT_24_0_EBX] | env->avx10_version;
> }
>
> Also, the check should use x86_cpu_get_supported_cpuid() because KVM is not
> the
> only accelerator.
>
Yes, I see, I add check here:
@@ -7679,6 +7719,27 @@ static void x86_cpu_realizefn(DeviceState *dev, Error
**errp)
x86_cpu_filter_features(cpu, cpu->check_cpuid || cpu->enforce_cpuid);
+ if (env->features[FEAT_7_1_EDX] & CPUID_7_1_EDX_AVX10) {
+ uint32_t eax, ebx, ecx, edx;
+ x86_cpu_get_supported_cpuid(0x24, 0, &eax, &ebx, &ecx, &edx);
+
+ ebx &= 0xff;
+
+ if (ebx < env->avx10_version) {
+ const char *msg = accel_uses_host_cpuid()
+ ? "Host doesn't support requested feature"
+ : "TCG doesn't support requested feature";
+ if (cpu->enforce_cpuid) {
+ error_setg(&local_err, "%s: avx10.%d", msg,
+ env->avx10_version);
+ goto out;
+ } else if (cpu->check_cpuid) {
+ warn_report("%s: avx10.%d", msg, env->avx10_version);
+ }
+ env->avx10_version = ebx;
+ }
+ }
+
if (cpu->enforce_cpuid && x86_cpu_have_filtered_features(cpu)) {
error_setg(&local_err,
accel_uses_host_cpuid() ?
>
> >
> > + if (env->features[FEAT_7_1_EDX] & CPUID_7_1_EDX_AVX10) {
> > + uint8_t version =
> > + kvm_arch_get_supported_cpuid(cs->kvm_state, 0x24, 0, R_EBX);
> > +
> > + if (!env->avx10_version) {
> > + env->avx10_version = version;
> > + }
> > +
>
> This should not be done here, but in max_x86_cpu_realize(). It should also
> use x86_cpu_get_supported_cpuid().
>
Yes, I try to add here:
@@ -5327,6 +5365,12 @@ static void max_x86_cpu_realize(DeviceState *dev, Error
**errp)
}
}
+ if (!object_property_get_uint(obj, "avx10-version", &error_abort)) {
+ uint32_t eax, ebx, ecx, edx;
+ x86_cpu_get_supported_cpuid(0x24, 0, &eax, &ebx, &ecx, &edx);
+ object_property_set_uint(obj, "avx10-version", ebx & 0xff,
&error_abort);
+ }
+
x86_cpu_realizefn(dev, errp);
}
> For Granite Rapids you're only setting the AVX10 version in v2 and therefore
> you don't need it, but there should also be (for the future) an avx10_version
> field in X86CPUDefinition, which is set into the avx10-version property at
> x86_cpu_load_model().
>
Yes, for new CPU model, we should do that.
> > index d845384dcd..5566a13f4f 100644
> > --- a/target/i386/cpu.h
> > +++ b/target/i386/cpu.h
> > @@ -662,6 +662,7 @@ typedef enum FeatureWord {
> > 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 */
> > + FEAT_24_0_EBX, /* CPUID[EAX=0x24,ECX=0].EBX */
>
> Adding FEAT_24_0_EBX should be a separate patch.
>
Yes, all you said above are excellent suggestions and I have tested on
my platform. Should I submit a v2 with these changes or wait for you to
send v2 directly? :-)
