Re: [Qemu-devel] [PATCH] vfio: Align iova also to IOMMU page size

[Peter Maydell]

On 3 December 2015 at 16:26, Alex Williamson <address@hidden> wrote:
> I feel a lot more comfortable if we limit the scope to MMIO regions of
> PCI devices.  The problems I brought up before about the device not
> being able to DMA to a target aligned RAM address are still a
> possibility that I think we want to catch.  To do that, I think we just
> need:
>
> Object *obj = memory_region_owner(section->mr);
>
> if (object_dynamic_cast(obj, "pci-device")) {
>     /* HOST_PAGE_ALIGN... */
> } else {
>     /* TARGET_PAGE_ALIGN... */
> }

This looks very odd to me, in two ways: (a) behaving differently
for PCI passthrough vs other kinds of passthrough, and (b) caring
about TARGET_PAGE_ALIGN at all. TARGET_PAGE_ALIGN really isn't
something vfio should need to care about I think.

thanks
-- PMM