From: Si-Wei Liu <si-wei....@oracle.com>
With _F_DESC_ASID backend feature, the device can now support the
VHOST_VDPA_GET_VRING_DESC_GROUP ioctl, and it may expose the descriptor
table (including avail and used ring) in a different group than the
buffers it contains. This new uAPI will fetch the group ID of the
descriptor table.
Signed-off-by: Si-Wei Liu <si-wei....@oracle.com>
Acked-by: Eugenio Pérez <epere...@redhat.com>
Acked-by: Jason Wang <jasow...@redhat.com>
---
drivers/vhost/vdpa.c | 10 ++++++++++
include/uapi/linux/vhost.h | 8 ++++++++
2 files changed, 18 insertions(+)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 2f21798a37ee..851535f57b95 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -613,6 +613,16 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v,
unsigned int cmd,
else if (copy_to_user(argp, &s, sizeof(s)))
return -EFAULT;
return 0;
+ case VHOST_VDPA_GET_VRING_DESC_GROUP:
+ if (!vhost_vdpa_has_desc_group(v))
+ return -EOPNOTSUPP;
+ s.index = idx;
+ s.num = ops->get_vq_desc_group(vdpa, idx);
+ if (s.num >= vdpa->ngroups)
+ return -EIO;
+ else if (copy_to_user(argp, &s, sizeof(s)))
+ return -EFAULT;
+ return 0;
case VHOST_VDPA_SET_GROUP_ASID:
if (copy_from_user(&s, argp, sizeof(s)))
return -EFAULT;
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index f5c48b61ab62..649560c685f1 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -219,4 +219,12 @@
*/
#define VHOST_VDPA_RESUME _IO(VHOST_VIRTIO, 0x7E)
+/* Get the group for the descriptor table including driver & device areas
+ * of a virtqueue: read index, write group in num.
+ * The virtqueue index is stored in the index field of vhost_vring_state.
+ * The group ID of the descriptor table for this specific virtqueue
+ * is returned via num field of vhost_vring_state.
+ */
+#define VHOST_VDPA_GET_VRING_DESC_GROUP _IOWR(VHOST_VIRTIO, 0x7F,
\
+ struct vhost_vring_state)
#endif
--
2.41.0
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