On Tue, Aug 18, 2026 at 1:32 AM Connor Kite <[email protected]> wrote: > > iova-tree expects inclusive range sizing when maps are allocated or searched. > Currently, svqs use exclusive sizing when searching their > vhost-iova-tree for a match to the region to be translated. This could > lead to errors if the region to be translated is at the edge of an iova > region. > > Fix this by reducing `needle.size` by 1 in > vhost_svq_translate_addr to bring it in line with DMAMap and iova-tree > convention. > > The only current user of svq->iova_tree is hw/virtio/vhost-vdpa.c, which > also treats size as inclusive when using the tree API. In progress work > on vhost-user isolation mode in hw/virtio.vhost-vdpa.c also uses > inclusive sizing when interacting with the tree. > > This patch is an updated version of one from the patch series "vhost-user: > isolated memory". The patch has been isolated from the series as it > is not tightly coupled with the rest of the series. > > Signed-off-by: Connor Kite <[email protected]> > Reviewed-by: Stefan Hajnoczi <[email protected]>
I'd like to improve the patch subject by adding a verb and the object. Something like (*add* range boundary in *vhost svq* translation). Also, adding the Fixes tag, Reviewed-by: Eugenio Pérez <[email protected]> Thank you very much for the catch! > --- > V2 Differences: > - Context added about users of svq->iova_tree and their adoption of > inclusive sizing > > hw/virtio/vhost-shadow-virtqueue.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/hw/virtio/vhost-shadow-virtqueue.c > b/hw/virtio/vhost-shadow-virtqueue.c > index bcb7f2ffc7..c8831d52be 100644 > --- a/hw/virtio/vhost-shadow-virtqueue.c > +++ b/hw/virtio/vhost-shadow-virtqueue.c > @@ -99,19 +99,25 @@ static bool vhost_svq_translate_addr(const > VhostShadowVirtqueue *svq, > const DMAMap *map; > DMAMap needle; > > + if (unlikely(iovec[i].iov_len == 0)) { > + qemu_log_mask(LOG_GUEST_ERROR, > + "Zero-sized buffer made available by guest"); > + return false; > + } > + > /* Check if the descriptor is backed by guest memory */ > if (gpas) { > /* Search the GPA->IOVA tree */ > needle = (DMAMap) { > .translated_addr = gpas[i], > - .size = iovec[i].iov_len, > + .size = iovec[i].iov_len - 1, /* Inclusive */ > }; > map = vhost_iova_tree_find_gpa(svq->iova_tree, &needle); > } else { > /* Search the IOVA->HVA tree */ > needle = (DMAMap) { > .translated_addr = (hwaddr)(uintptr_t)iovec[i].iov_base, > - .size = iovec[i].iov_len, > + .size = iovec[i].iov_len - 1, /* Inclusive */ > }; > map = vhost_iova_tree_find_iova(svq->iova_tree, &needle); > } > -- > 2.43.0 >
