Re: [RFC v3 2/5] vhost-iova-tree: Remove range check for IOVA allocator

[Jonah Palmer]

On 1/16/25 12:02 PM, Eugenio Perez Martin wrote:
> On Fri, Jan 10, 2025 at 6:09 PM Jonah Palmer <jonah.palmer@oracle.com> wrote:
> > Removes the range check portion in vhost_iova_tree_map_alloc.
> >
> > The previous patch decoupled the IOVA allocator from adding mappings to
> > the IOVA->HVA tree (now a partial SVQ IOVA->HVA tree) and instead adds
> > the allocated IOVA range to an IOVA-only tree. No value exists under
> > translated_addr for the IOVA-only mappings, so this check is no longer
> > needed.
> >
> > This check was moved to vhost_iova_tree_insert in the previous patch
> > since that function handles adding IOVA->HVA mappings to the SVQ
> > IOVA->HVA tree.
> >
> > Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
> > ---
> >   hw/virtio/vhost-iova-tree.c | 3 +--
> >   1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/hw/virtio/vhost-iova-tree.c b/hw/virtio/vhost-iova-tree.c
> > index b1cfd17843..f6a5694857 100644
> > --- a/hw/virtio/vhost-iova-tree.c
> > +++ b/hw/virtio/vhost-iova-tree.c
> > @@ -93,8 +93,7 @@ int vhost_iova_tree_map_alloc(VhostIOVATree *tree, DMAMap 
> > *map)
> >       /* Some vhost devices do not like addr 0. Skip first page */
> >       hwaddr iova_first = tree->iova_first ?: qemu_real_host_page_size();
>
> This is not a static function, so I guess it is better to duplicate
> the check if needed? Otherwise a buggy caller can create invalid
> entries.

Gotcha. I can drop this patch then.

> > -    if (map->translated_addr + map->size < map->translated_addr ||
> > -        map->perm == IOMMU_NONE) {
> > +    if (map->perm == IOMMU_NONE) {
> >           return IOVA_ERR_INVALID;
> >       }
> >
> > --
> > 2.43.5