Re: [PATCH 06/11] kvm: Change kvm_iommu_map_pages to map large pages

Joerg Roedel
2010-01-29T09:32:33Z

On Thu, Jan 28, 2010 at 08:24:55PM -0200, Marcelo Tosatti wrote:
> On Thu, Jan 28, 2010 at 12:37:57PM +0100, Joerg Roedel wrote:
> > +static pfn_t kvm_pin_pages(struct kvm *kvm, struct kvm_memory_slot *slot,
> > + gfn_t gfn, unsigned long size)
> > +{
> > + gfn_t end_gfn;
> > + pfn_t pfn;
> > +
> > + pfn = gfn_to_pfn_memslot(kvm, slot, gfn);
>
> If gfn_to_pfn_memslot returns pfn of bad_page, you might create a
> large iommu translation for it?

Right. But that was broken even before this patch. Anyway, I will fix
it.

> > + /* Map into IO address space */
> > + r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
> > + get_order(page_size), flags);
> > +
> > + gfn += page_size >> PAGE_SHIFT;
>
> Should increase gfn after checking for failure, otherwise wrong
> npages is passed to kvm_iommu_put_pages.

True. Will fix that too.

Thanks,

Joerg