| Message ID | 20230823153032.239304-1-eric.auger@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vhost: Allow null msg.size on VHOST_IOTLB_INVALIDATE | expand |
On Wed, Aug 23, 2023 at 11:30 PM Eric Auger <eric.auger@redhat.com> wrote: > > Commit e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb > entries") Forbade vhost iotlb msg with null size to prevent entries > with size = start = 0 and last = ULONG_MAX to end up in the iotlb. > > Then commit 95932ab2ea07 ("vhost: allow batching hint without size") > only applied the check for VHOST_IOTLB_UPDATE and VHOST_IOTLB_INVALIDATE > message types to fix a regression observed with batching hit. > > Still, the introduction of that check introduced a regression for > some users attempting to invalidate the whole ULONG_MAX range by > setting the size to 0. This is the case with qemu/smmuv3/vhost > integration which does not work anymore. It Looks safe to partially > revert the original commit and allow VHOST_IOTLB_INVALIDATE messages > with null size. vhost_iotlb_del_range() will compute a correct end > iova. Same for vhost_vdpa_iotlb_unmap(). > > Signed-off-by: Eric Auger <eric.auger@redhat.com> Cc: stable@vger.kernel.org I think we need to document the usage of 0 as msg.size for IOTLB_INVALIDATE in uapi. Other than this: Acked-by: Jason Wang <jasowang@redhat.com> Thanks > Fixes: e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb entries") > --- > drivers/vhost/vhost.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index c71d573f1c94..e0c181ad17e3 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -1458,9 +1458,7 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev, > goto done; > } > > - if ((msg.type == VHOST_IOTLB_UPDATE || > - msg.type == VHOST_IOTLB_INVALIDATE) && > - msg.size == 0) { > + if (msg.type == VHOST_IOTLB_UPDATE && msg.size == 0) { > ret = -EINVAL; > goto done; > } > -- > 2.41.0 >
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index c71d573f1c94..e0c181ad17e3 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1458,9 +1458,7 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev, goto done; } - if ((msg.type == VHOST_IOTLB_UPDATE || - msg.type == VHOST_IOTLB_INVALIDATE) && - msg.size == 0) { + if (msg.type == VHOST_IOTLB_UPDATE && msg.size == 0) { ret = -EINVAL; goto done; }
Commit e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb entries") Forbade vhost iotlb msg with null size to prevent entries with size = start = 0 and last = ULONG_MAX to end up in the iotlb. Then commit 95932ab2ea07 ("vhost: allow batching hint without size") only applied the check for VHOST_IOTLB_UPDATE and VHOST_IOTLB_INVALIDATE message types to fix a regression observed with batching hit. Still, the introduction of that check introduced a regression for some users attempting to invalidate the whole ULONG_MAX range by setting the size to 0. This is the case with qemu/smmuv3/vhost integration which does not work anymore. It Looks safe to partially revert the original commit and allow VHOST_IOTLB_INVALIDATE messages with null size. vhost_iotlb_del_range() will compute a correct end iova. Same for vhost_vdpa_iotlb_unmap(). Signed-off-by: Eric Auger <eric.auger@redhat.com> Fixes: e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb entries") --- drivers/vhost/vhost.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)