On Wed, 2 Oct 2013 17:54:57 +0200
Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> The data in leaf 0Dh depends on information from other feature bits.
> Instead of passing it blindly from the host, compute it based on
> whether these feature bits are enabled.
>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> target-i386/cpu.c | 65 ++++++++++++++++++++++++++++++++++++++++---------------
> 1 file changed, 48 insertions(+), 17 deletions(-)
>
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index ac83106..1addb18 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -328,6 +328,15 @@ X86RegisterInfo32 x86_reg_info_32[CPU_NB_REGS32] = {
> };
> #undef REGISTER
>
> +typedef struct ExtSaveArea {
> + uint32_t feature, bits;
> + uint32_t offset, size;
> +} ExtSaveArea;
> +
> +static const ExtSaveArea ext_save_areas[] = {
> + [2] = { .feature = FEAT_1_ECX, .bits = CPUID_EXT_AVX,
> + .offset = 0x100, .size = 0x240 },
> +};
>
> const char *get_register_name_32(unsigned int reg)
> {
> @@ -2169,29 +2178,51 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
> *edx = 0;
> }
> break;
> - case 0xD:
> + case 0xD: {
> + KVMState *s = cs->kvm_state;
> + uint64_t kvm_mask;
> + int i;
> +
> /* Processor Extended State */
> - if (!(env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE)) {
> - *eax = 0;
> - *ebx = 0;
> - *ecx = 0;
> - *edx = 0;
> + *eax = 0;
> + *ebx = 0;
> + *ecx = 0;
> + *edx = 0;
> + if (!(env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE) || !kvm_enabled()) {
> break;
> }
> - if (kvm_enabled()) {
> - KVMState *s = cs->kvm_state;
> + kvm_mask =
> + kvm_arch_get_supported_cpuid(s, 0xd, 0, R_EAX) |
> + ((uint64_t)kvm_arch_get_supported_cpuid(s, 0xd, 0, R_EDX) << 32);
calling kvm_arch_get_supported_cpuid() without kvm_enabled() guard
could regress TCG mode on non KVM host:
kvm_arch_get_supported_cpuid -> get_supported_cpuid -> try_get_cpuid ->
r = kvm_ioctl(s, KVM_GET_SUPPORTED_CPUID, cpuid);
...
if (r < 0) {
if (r == -E2BIG) {
g_free(cpuid);
return NULL;
} else {
fprintf(stderr, "KVM_GET_SUPPORTED_CPUID failed: %s\n",
strerror(-r));
exit(1);
^^^^^^^^^ guest suddenly dies
>
> - *eax = kvm_arch_get_supported_cpuid(s, 0xd, count, R_EAX);
> - *ebx = kvm_arch_get_supported_cpuid(s, 0xd, count, R_EBX);
> - *ecx = kvm_arch_get_supported_cpuid(s, 0xd, count, R_ECX);
> - *edx = kvm_arch_get_supported_cpuid(s, 0xd, count, R_EDX);
> - } else {
> - *eax = 0;
> - *ebx = 0;
> - *ecx = 0;
> - *edx = 0;
> + if (count == 0) {
> + *ecx = 0x240;
> + for (i = 2; i < ARRAY_SIZE(ext_save_areas); i++) {
> + const ExtSaveArea *esa = &ext_save_areas[i];
> + if ((env->features[esa->feature] & esa->bits) == esa->bits &&
> + (kvm_mask & (1 << i)) != 0) {
> + if (i < 32) {
> + *eax |= 1 << i;
> + } else {
> + *edx |= 1 << (i - 32);
> + }
> + *ecx = MAX(*ecx, esa->offset + esa->size);
> + }
> + }
> + *eax |= kvm_mask & (XSTATE_FP | XSTATE_SSE);
> + *ebx = *ecx;
> + } else if (count == 1) {
> + *eax = kvm_arch_get_supported_cpuid(s, 0xd, 1, R_EAX);
> + } else if (count < ARRAY_SIZE(ext_save_areas)) {
> + const ExtSaveArea *esa = &ext_save_areas[count];
> + if ((env->features[esa->feature] & esa->bits) == esa->bits &&
> + (kvm_mask & (1 << count)) != 0) {
> + *eax = esa->offset;
> + *ebx = esa->size;
> + }
> }
> break;
> + }
> case 0x80000000:
> *eax = env->cpuid_xlevel;
> *ebx = env->cpuid_vendor1;
--
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