Re: [PATCH 1/4] x86: introduce hypervisor_cpuid_base()

H. Peter Anvin
2013-07-23T10:04:44Z

On 07/23/2013 02:41 AM, Jason Wang wrote:
>
> +static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves)
> +{
> + uint32_t base, eax, ebx, ecx, edx;
> + char signature[13];
> +
> + for (base = 0x40000000; base < 0x40010000; base += 0x100) {
> + cpuid(base, &eax, &ebx, &ecx, &edx);
> + *(uint32_t *)(signature + 0) = ebx;
> + *(uint32_t *)(signature + 4) = ecx;
> + *(uint32_t *)(signature + 8) = edx;
> + signature[12] = 0;
> +
> + if (!strcmp(sig, signature) &&
> + (leaves == 0 || ((eax - base) >= leaves)))
> + return base;
> + }
> +
> + return 0;
> +}
> +

Hmm... how about:

uint32_t sign[3];

cpuid(base, &eax, &sign[0], &sign[1], &sign[2]);

if (!memcmp(sig, sign, 12) && ...);

-hpa