Re: [Qemu-devel] CPUID feature bits not saved with migration

[Anthony Liguori]

Andre Przywara wrote:
> Hi,
>
> while testing the guest multi-core code, I realized that all of the 
> cpuid_* values (like cpuid_ext_features,...) from CPUX86State are not 
> dumped in the migration stream. Is this intentional behavior (to let 
> the user specify other bits in the target?) or has this just been 
> forgotten?
> Does KVM call the SET_CPUID2 ioctl after or before migration?

The cpuid bits are specified by the user.  They aren't changable by the 
guest which is why they haven't been migrated.

It's unclear what to do about -cpu host.  If we did migrate cpuid 
values, then -cpu would effectively be ignored after an incoming migration.

Regards,

Anthony Liguori

> Regards,
> Andre.