[Qemu-devel] Re: [kvm-devel] [PATCH][UPDATE] kvm-userspace: sync icache for morearchitectures

[Christian Ehrhardt]

Hollis Blanchard wrote:
> On Fri, 2007-12-14 at 10:07 +0100, Christian Ehrhardt wrote:
> > Hollis Blanchard wrote:
> > > A comment to explain why the icache needs flushing only in the KVM
> > case
> > > would be useful. Other than that I'm fine with it.
> > >
> > > Signed-off-by: Hollis Blanchard <address@hidden>
> > AFAIK Plain qemu does not directly execute guest code on the
> > processor,
> > so the icache is not an issue for it.
> > Qemu itself has the flush_icache_range function only as helper for the
> > dynamic code generation.
> > But we may now write executable guest code with our intercepted mmio
> > handling that is directly executed when switching back to the guest
> > context, therefore we need that invalidation in the kvm case.
> >
> > For the case that I'm overlooking something in plain qemu, so that it
> > might need it too I add address@hidden for comments from there,
> > but currently I think to have it in #ifdef USE_KVM is the right way.
> >
> >
> > P.S. Hollis did you mean you would like to see a comment in the code
> > where that call takes place?
>
> Yes! Hopefully much shorter than this email... :-P
comment added, rebased and resent together with a updated mmio
callback simplification patch - I hope I didn't overlook a response
to the mmio callback thread again this time ;-)

--

Grüsse / regards, 
Christian Ehrhardt

IBM Linux Technology Center, Open Virtualization
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