vdpa: support packed virtqueue for set/get_vq_state()

This patch extends the vdpa_vq_state to support packed virtqueue
state which is basically the device/driver ring wrap counters and the
avail and used index. This will be used for the virito-vdpa support
for the packed virtqueue and the future vhost/vhost-vdpa support for
the packed virtqueue.

Signed-off-by: Jason Wang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Michael S. Tsirkin <[e-mail]>
Reviewed-by: Eli Cohen <[e-mail]>

drivers/vdpa/ifcvf/ifcvf_main.c

···
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
 
-	state->avail_index = ifcvf_get_vq_state(vf, qid);
+	state->split.avail_index = ifcvf_get_vq_state(vf, qid);
 	return 0;
 }
 
···
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
 
-	return ifcvf_set_vq_state(vf, qid, state->avail_index);
+	return ifcvf_set_vq_state(vf, qid, state->split.avail_index);
 }
 
 static void ifcvf_vdpa_set_vq_cb(struct vdpa_device *vdpa_dev, u16 qid,

drivers/vdpa/mlx5/net/mlx5_vnet.c

···
 		return -EINVAL;
 	}
 
-	mvq->used_idx = state->avail_index;
-	mvq->avail_idx = state->avail_index;
+	mvq->used_idx = state->split.avail_index;
+	mvq->avail_idx = state->split.avail_index;
 	return 0;
 }
 
···
 		 * Since both values should be identical, we take the value of
 		 * used_idx which is reported correctly.
 		 */
-		state->avail_index = mvq->used_idx;
+		state->split.avail_index = mvq->used_idx;
 		return 0;
 	}
 
···
 		mlx5_vdpa_warn(mvdev, "failed to query virtqueue\n");
 		return err;
 	}
-	state->avail_index = attr.used_index;
+	state->split.avail_index = attr.used_index;
 	return 0;
 }
 

drivers/vdpa/vdpa_sim/vdpa_sim.c

···
 	struct vringh *vrh = &vq->vring;
 
 	spin_lock(&vdpasim->lock);
-	vrh->last_avail_idx = state->avail_index;
+	vrh->last_avail_idx = state->split.avail_index;
 	spin_unlock(&vdpasim->lock);
 
 	return 0;
···
 	struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 	struct vringh *vrh = &vq->vring;
 
-	state->avail_index = vrh->last_avail_idx;
+	state->split.avail_index = vrh->last_avail_idx;
 	return 0;
 }
 

drivers/vhost/vdpa.c

···
 		if (r)
 			return r;
 
-		vq->last_avail_idx = vq_state.avail_index;
+		vq->last_avail_idx = vq_state.split.avail_index;
 		break;
 	}
 
···
 		break;
 
 	case VHOST_SET_VRING_BASE:
-		vq_state.avail_index = vq->last_avail_idx;
+		vq_state.split.avail_index = vq->last_avail_idx;
 		if (ops->set_vq_state(vdpa, idx, &vq_state))
 			r = -EINVAL;
 		break;

include/linux/vdpa.h

···
 };
 
 /**
- * struct vdpa_vq_state - vDPA vq_state definition
+ * struct vdpa_vq_state_split - vDPA split virtqueue state
  * @avail_index: available index
  */
-struct vdpa_vq_state {
+struct vdpa_vq_state_split {
 	u16	avail_index;
+};
+
+/**
+ * struct vdpa_vq_state_packed - vDPA packed virtqueue state
+ * @last_avail_counter: last driver ring wrap counter observed by device
+ * @last_avail_idx: device available index
+ * @last_used_counter: device ring wrap counter
+ * @last_used_idx: used index
+ */
+struct vdpa_vq_state_packed {
+        u16	last_avail_counter:1;
+        u16	last_avail_idx:15;
+        u16	last_used_counter:1;
+        u16	last_used_idx:15;
+};
+
+struct vdpa_vq_state {
+     union {
+          struct vdpa_vq_state_split split;
+          struct vdpa_vq_state_packed packed;
+     };
 };
 
 struct vdpa_mgmt_dev;