Re: [PATCH v1 02/26] x86/cpu: Sanitize CPUID(0x80000000) output

From: H. Peter Anvin
Date: Thu May 08 2025 - 16:42:15 EST


On May 7, 2025 1:50:48 AM PDT, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
>On 06/05/2025 6:04 am, Ahmed S. Darwish wrote:
>> CPUID(0x80000000).EAX returns the max extended CPUID leaf available. On
>> x86-32 machines
>
>How certain are you that it's all 32bit CPUs?  AIUI, it's an Intel
>specific behaviour, not shared by other x86 vendors of the same era.
>
>~Andrew

All 64-bit machines require CPUID leaf 0x80000000.