virtio: record the maximum queue num supported by the device.

virtio-net can display the maximum (supported by hardware) ring size in
ethtool -g eth0.

When the subsequent patch implements vring reset, it can judge whether
the ring size passed by the driver is legal based on this.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220801063902.129329-2-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

arch/um/drivers/virtio_uml.c

@@ -958,6 +958,7 @@ static struct virtqueue *vu_setup_vq(struct virtio_device *vdev,
 		goto error_create;
 	}
 	vq->priv = info;
+	vq->num_max = num;
 	num = virtqueue_get_vring_size(vq);
 
 	if (vu_dev->protocol_features &

drivers/platform/mellanox/mlxbf-tmfifo.c

@@ -959,6 +959,8 @@ static int mlxbf_tmfifo_virtio_find_vqs(struct virtio_device *vdev,
 			goto error;
 		}
 
+		vq->num_max = vring->num;
+
 		vqs[i] = vq;
 		vring->vq = vq;
 		vq->priv = vring;

drivers/remoteproc/remoteproc_virtio.c

@@ -125,6 +125,8 @@ static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
 		return ERR_PTR(-ENOMEM);
 	}
 
+	vq->num_max = num;
+
 	rvring->vq = vq;
 	vq->priv = rvring;
 

drivers/s390/virtio/virtio_ccw.c

@@ -530,6 +530,9 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
 		err = -ENOMEM;
 		goto out_err;
 	}
+
+	vq->num_max = info->num;
+
 	/* it may have been reduced */
 	info->num = virtqueue_get_vring_size(vq);
 

drivers/virtio/virtio_mmio.c

@@ -403,6 +403,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
 		goto error_new_virtqueue;
 	}
 
+	vq->num_max = num;
+
 	/* Activate the queue */
 	writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
 	if (vm_dev->version == 1) {

drivers/virtio/virtio_pci_legacy.c

@@ -135,6 +135,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 	if (!vq)
 		return ERR_PTR(-ENOMEM);
 
+	vq->num_max = num;
+
 	q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
 	if (q_pfn >> 32) {
 		dev_err(&vp_dev->pci_dev->dev,

drivers/virtio/virtio_pci_modern.c

@@ -218,6 +218,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 	if (!vq)
 		return ERR_PTR(-ENOMEM);
 
+	vq->num_max = num;
+
 	/* activate the queue */
 	vp_modern_set_queue_size(mdev, index, virtqueue_get_vring_size(vq));
 	vp_modern_queue_address(mdev, index, virtqueue_get_desc_addr(vq),

drivers/virtio/virtio_vdpa.c

@@ -183,6 +183,8 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
 		goto error_new_virtqueue;
 	}
 
+	vq->num_max = max_num;
+
 	/* Setup virtqueue callback */
 	cb.callback = callback ? virtio_vdpa_virtqueue_cb : NULL;
 	cb.private = info;

include/linux/virtio.h

@@ -19,6 +19,7 @@
  * @priv: a pointer for the virtqueue implementation to use.
  * @index: the zero-based ordinal number for this queue.
  * @num_free: number of elements we expect to be able to fit.
+ * @num_max: the maximum number of elements supported by the device.
  *
  * A note on @num_free: with indirect buffers, each buffer needs one
  * element in the queue, otherwise a buffer will need one element per
@@ -31,6 +32,7 @@ struct virtqueue {
 	struct virtio_device *vdev;
 	unsigned int index;
 	unsigned int num_free;
+	unsigned int num_max;
 	void *priv;
 };