Re: [Qemu-devel] How does the QEMU load the binary files bios.bin and vgabios-cirrus.bin?

[Gleb Natapov]

On Thu, Apr 07, 2011 at 04:34:38PM -0500, Anthony Liguori wrote:
> On 04/07/2011 02:31 PM, Gleb Natapov wrote:
> >
> >Remapping part is easy. As you are saying QEMU already does remapping,
> 
> Yes.
> 
> >the only thing missing is creating/destroying/remapping KVM memory slot
> >(with SMP it is slightly more complicated, but doable).
> 
> Yup.  It's not impossible but not free.
> 
> >  But after doing
> >this SMM will not Just Work in KVM on Intel because VMX does not support
> >SMM mode and it can't be approximated by vm86, so KVM will have to emulate
> >every single instruction while in SMM mode and this like will not work.
> 
> Isn't everyone using Westmere's at this point with unrestricted
> guest mode :-)
> 
> BTW, I assume that there's some kernel logic needed to enable SMM
> intercepts but I'm not entirely sure what's involved there.
> 
Vcpu needs to know that it is in SMM mode and memory slot logic should
be changed to lookup slots according to vcpu mode. This is needed
because the same physical address can be treated as frame buffer by one
cpu and as a regular memory by other simultaneously in SMP system.

--
                        Gleb.