This is a note to let you know that I've just added the patch titled
vhost: support PACKED when setting-getting vring_base
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vhost-support-packed-when-setting-getting-vring_base.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2ccb6b174fc2525b5056ea81e91d4926b12cfe48
Author: Shannon Nelson <shannon.nelson@xxxxxxx>
Date: Mon Apr 24 15:50:30 2023 -0700
vhost: support PACKED when setting-getting vring_base
[ Upstream commit 55d8122f5cd62d5aaa225d7167dcd14a44c850b9 ]
Use the right structs for PACKED or split vqs when setting and
getting the vring base.
Fixes: 4c8cf31885f6 ("vhost: introduce vDPA-based backend")
Signed-off-by: Shannon Nelson <shannon.nelson@xxxxxxx>
Message-Id: <20230424225031.18947-3-shannon.nelson@xxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c0f926a9c298f..047fa2faef566 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1628,17 +1628,25 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg
r = -EFAULT;
break;
}
- if (s.num > 0xffff) {
- r = -EINVAL;
- break;
+ if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
+ vq->last_avail_idx = s.num & 0xffff;
+ vq->last_used_idx = (s.num >> 16) & 0xffff;
+ } else {
+ if (s.num > 0xffff) {
+ r = -EINVAL;
+ break;
+ }
+ vq->last_avail_idx = s.num;
}
- vq->last_avail_idx = s.num;
/* Forget the cached index value. */
vq->avail_idx = vq->last_avail_idx;
break;
case VHOST_GET_VRING_BASE:
s.index = idx;
- s.num = vq->last_avail_idx;
+ if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+ s.num = (u32)vq->last_avail_idx | ((u32)vq->last_used_idx << 16);
+ else
+ s.num = vq->last_avail_idx;
if (copy_to_user(argp, &s, sizeof s))
r = -EFAULT;
break;
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index f2675c0aa08ee..6378f020e6d53 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -86,13 +86,17 @@ struct vhost_virtqueue {
/* The routine to call when the Guest pings us, or timeout. */
vhost_work_fn_t handle_kick;
- /* Last available index we saw. */
+ /* Last available index we saw.
+ * Values are limited to 0x7fff, and the high bit is used as
+ * a wrap counter when using VIRTIO_F_RING_PACKED. */
u16 last_avail_idx;
/* Caches available index value from user. */
u16 avail_idx;
- /* Last index we used. */
+ /* Last index we used.
+ * Values are limited to 0x7fff, and the high bit is used as
+ * a wrap counter when using VIRTIO_F_RING_PACKED. */
u16 last_used_idx;
/* Used flags */
