Re: [PATCH] memory: Optimize replay of guest mapping

[Peter Xu <peterx@redhat.com>]

On Tue, Feb 14, 2023 at 07:04:56AM +0000, Duan, Zhenzhong wrote:
> >> @@ -1936,7 +1935,7 @@ void
> >> memory_region_iommu_replay(IOMMUMemoryRegion *iommu_mr,
> >IOMMUNotifier
> >> *n)
> >>
> >>      granularity = memory_region_iommu_get_min_page_size(iommu_mr);
> >>
> >> -    for (addr = 0; addr < memory_region_size(mr); addr += granularity) {
> >> +    for (addr = n->start; addr < n->end; addr += granularity) {
> >
> >Is [n->start, n->end] guaranteed to be the subset of memory_region_size(mr)?
> 
> In current implementation it is.
> [n->start, n->end] of notifier is derived from iommu memory region's section
> which is a subset of iommu memory region itself.

Yes, currently it seems to be guaranteed by the callers assuming they're
always doing the right thing.

Maybe it'll worth it to have memory_region_register_iommu_notifier() assert
properly to make sure it always hold true?

The patch itself looks good here, thanks.

-- 
Peter Xu