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SubjectRe: [PATCH] KVM: x86: work around QEMU issue with synthetic CPUID leaves
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On 5/1/22 13:16, Maxim Levitsky wrote:
>> + * However, only do it if the host has CPUID leaf 0x8000001d.
>> + * QEMU thinks that it can query the host blindly for that
>> + * CPUID leaf if KVM reports that it supports 0x8000001d or
>> + * above. The processor merrily returns values from the
>> + * highest Intel leaf which QEMU tries to use as the guest's
>> + * 0x8000001d. Even worse, this can result in an infinite
>> + * loop if said highest leaf has no subleaves indexed by ECX.
>
> Very small nitpick: It might be useful to add a note that qemu does this only for the
> leaf 0x8000001d.

Yes, it's there: "QEMU thinks that it can query the host blindly for
that CPUID leaf", "that" is 0x8000001d in the previous sentence.

Paolo

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