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

[Hollis Blanchard <hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>]

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 <hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
> 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 qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org 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

-- 
Hollis Blanchard
IBM Linux Technology Center


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