Re: [PATCH 1/4] vhost: handle VHOST_USER_SET_LOG_BASE request

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

On Mon, Dec 07, 2015 at 12:07:28AM +0100, Thomas Monjalon wrote:
> 2015-12-02 15:53, Panu Matilainen:
> > This (and other changes in patch 2 breaks the librte_vhost ABI again, so 
> > you'd need to at least add a deprecation note to 2.2 to be able to do it 
> > in 2.3 at all according to the ABI policy.
> > 
> > Perhaps a better option would be adding some padding to the structs now 
> > for 2.2 since the vhost ABI is broken there anyway. That would at least 
> > give a chance to keep it compatible from 2.2 to 2.3.
> 
> Please could you point where the vhost ABI is broken in 2.2?

Thomas, here are the changes to rte_virtio_net.h:


$ git diff 381316f6a225139d22d39b5ab8d50c40607924ca..19d4d7ef2a216b5418d8edb5b004d1a58bba3cc1 \
      -- lib/librte_vhost/rte_virtio_net.h >
diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
index e3a21e5..426a70d 100644
--- a/lib/librte_vhost/rte_virtio_net.h
+++ b/lib/librte_vhost/rte_virtio_net.h
@@ -89,6 +89,7 @@ struct vhost_virtqueue {
 	volatile uint16_t	last_used_idx_res;	/**< Used for multiple devices reserving buffers. */
 	int			callfd;			/**< Used to notify the guest (trigger interrupt). */
 	int			kickfd;			/**< Currently unused as polling mode is enabled. */
+	int			enabled;
 	struct buf_vector	buf_vec[BUF_VECTOR_MAX];	/**< for scatter RX. */
 } __rte_cache_aligned;
 
@@ -96,7 +97,6 @@ struct vhost_virtqueue {
  * Device structure contains all configuration information relating to the device.
  */
 struct virtio_net {
-	struct vhost_virtqueue	*virtqueue[VIRTIO_QNUM];	/**< Contains all virtqueue information. */
 	struct virtio_memory	*mem;		/**< QEMU memory and memory region information. */
 	uint64_t		features;	/**< Negotiated feature set. */
 	uint64_t		protocol_features;	/**< Negotiated protocol feature set. */
@@ -104,7 +104,9 @@ struct virtio_net {
 	uint32_t		flags;		/**< Device flags. Only used to check if device is running on data core. */
 #define IF_NAME_SZ (PATH_MAX > IFNAMSIZ ? PATH_MAX : IFNAMSIZ)
 	char			ifname[IF_NAME_SZ];	/**< Name of the tap device or socket path. */
+	uint32_t		virt_qp_nb;	/**< number of queue pair we have allocated */
 	void			*priv;		/**< private context */
+	struct vhost_virtqueue	*virtqueue[VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX];	/**< Contains all virtqueue information. */
 } __rte_cache_aligned;
 
 /**
@@ -131,7 +133,7 @@ struct virtio_memory {
 };
 
 /**
- * Device operations to add/remove device.
+ * Device and vring operations.
  *
  * Make sure to set VIRTIO_DEV_RUNNING to the device flags in new_device and
  * remove it in destroy_device.
@@ -140,12 +142,18 @@ struct virtio_memory {
 struct virtio_net_device_ops {
 	int (*new_device)(struct virtio_net *);	/**< Add device. */
 	void (*destroy_device)(volatile struct virtio_net *);	/**< Remove device. */
+
+	int (*vring_state_changed)(struct virtio_net *dev, uint16_t queue_id, int enable);	/**< triggered when a vring is enabled or disabled */
 };
 
 static inline uint16_t __attribute__((always_inline))
 rte_vring_available_entries(struct virtio_net *dev, uint16_t queue_id)
 {
 	struct vhost_virtqueue *vq = dev->virtqueue[queue_id];
+
+	if (!vq->enabled)
+		return 0;
+
 	return *(volatile uint16_t *)&vq->avail->idx - vq->last_used_idx_res;
 }
 

	--yliu