Re: [Qemu-devel] [edk2] [RFC PATCH] Distinguish between reset types

[Anthony Liguori]

Paolo Bonzini <address@hidden> writes:

> Il 21/02/2013 18:12, David Woodhouse ha scritto:
>>> > Since
>>> > - I like kvm, and
>>> > - I cannot easily change my hardware (which doesn't support UG), and
>>> > - I prefer to run the RHEL-6 kernel which has "old" KVM,
>>> > I depend on David's fix for the PAM registers.
>> Which means your suspend/resume is broken. Yay! :)
>> 
>> Anthony's patchset should hopefully fix that.
>> 
>> I wonder what it would take to work around the KVM bug in qemu though;
>> can we actually *emulate* 16-bit mode instead of using KVM, on the
>> kernels where KVM is broken? And then transition back to using KVM when
>> we switch to 32-bit or 64-bit mode?
>
> I don't think you want to do that.  It would be really slow, it would
> trade some emulation bugs for others, and people who mind security would
> not appreciate the additional attack surface of TCG.
>
> (BTW, that's how the very first version of KVM worked.  It didn't use
> hardware virtualization at all until entering 64-bit mode, IIRC).

Pre-released versions, yes.  Avi started with emulating up to 64-bit and
worked up from there.  None of the public versions ever implemented
this.

Regards,

Anthony Liguori

>
> I think we just have to fix it in 1.5, and suggest a newer kernel to
> everyone else.
>
> Paolo