Re: [Qemu-devel] [RFC] Memory API

[Anthony Liguori]

On 05/19/2011 03:30 AM, Jan Kiszka wrote:
> On 2011-05-19 10:26, Gleb Natapov wrote:
> > On Wed, May 18, 2011 at 09:27:55PM +0200, Jan Kiszka wrote:
> > > > if an I/O is to the APIC page,
> > > >     it's handled by the APIC
> > >
> > > That's not that simple. We need to tell apart:
> > >   - if a cpu issued the request, and which one =>  forward to APIC
> > And cpu mode may affect where access is forwarded to. If cpu is in SMM
> > mode access to frame buffer may be forwarded to a memory (depends on
> > chipset configuration).
>
> So we have a second use case for CPU-local I/O regions?
>
> I wonder if only a single CPU can enter SMM or if all have to.

For the i440fx, it's a chipset register (not a per-CPU register).

Maybe it's per-CPU on more modern chipsets... I'm not really sure.

Regards,

Anthony Liguori