Re: [PATCH v6 1/6] OvmfPkg/BaseMemEncryptLib: Detect SEV live migration feature.


Lendacky, Thomas
 

On 8/10/21 1:05 AM, Gerd Hoffmann wrote:
Hi,

I still really don't understand the need for the CPUID loop. KVM only ever
programs CPUID function 0x40000000, right?
Nope. When you enable hyper-v emulation features you'll go find the kvm
cpuid @ 0x40000000 and the hyper-v cpuid @ 0x40000100 (or the other way
around, not sure).
Ah, thanks. I just saw the comment above get_out_of_range_cpuid_entry() in
arch/x86/kvm/cpuid.c where HyperV would get the 0x40000000-0x400000ff
range and KVM would then get the 0x40000100-0x400001ff range (basically
each hypervisor class gets their own 0x100 range).

Thanks,
Tom


take care,
Gerd

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