Re: [RFC PATCH 8/8] target/i386: Move X86XSaveArea into TCG

[David Edmondson]

On Thursday, 2021-07-08 at 08:22:02 -07, Richard Henderson wrote:

> On 7/8/21 12:45 AM, David Edmondson wrote:
>> Actually, that's nonsense. With KVM or HVF we have to use the offsets of
>> the host CPU, as the hardware won't do anything else, irrespective of
>> the general CPU model chosen.
>> 
>> To have KVM -> TCG migration work it would be necessary to pass the
>> offsets in the migration stream and have TCG observe them, as you
>> originally said.
>> 
>> TCG -> KVM migration would only be possible if TCG was configured to use
>> the same offsets as would later required by KVM (meaning, the host CPU).
>
> And kvm -> kvm migration, with the same general cpu model chosen, but with 
> different host 
> cpus with different offsets?
>
> It seems like we must migrate then and verify the offsets in that case, so 
> that we can 
> fail the migration.

Agreed.

I will look into migrating the offsets.

dme.
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