virtio-pci-modern: introduce helper to set/get queue_enable

This patch introduces a helper to set/get queue_enable for modern device.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210104065503.199631-12-jasowang@redhat.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/virtio/virtio_pci_modern.c

@@ -234,6 +234,34 @@ static void vp_modern_queue_address(struct virtio_pci_modern_device *mdev,
 			     &cfg->queue_used_hi);
 }
 
+/*
+ * vp_modern_set_queue_enable - enable a virtqueue
+ * @mdev: the modern virtio-pci device
+ * @index: the queue index
+ * @enable: whether the virtqueue is enable or not
+ */
+static void vp_modern_set_queue_enable(struct virtio_pci_modern_device *mdev,
+				       u16 index, bool enable)
+{
+	vp_iowrite16(index, &mdev->common->queue_select);
+	vp_iowrite16(enable, &mdev->common->queue_enable);
+}
+
+/*
+ * vp_modern_get_queue_enable - enable a virtqueue
+ * @mdev: the modern virtio-pci device
+ * @index: the queue index
+ *
+ * Returns whether a virtqueue is enabled or not
+ */
+static bool vp_modern_get_queue_enable(struct virtio_pci_modern_device *mdev,
+				       u16 index)
+{
+	vp_iowrite16(index, &mdev->common->queue_select);
+
+	return vp_ioread16(&mdev->common->queue_enable);
+}
+
 /* virtio config->finalize_features() implementation */
 static int vp_finalize_features(struct virtio_device *vdev)
 {
@@ -460,7 +488,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 
 	/* Check if queue is either not available or already active. */
 	num = vp_ioread16(&cfg->queue_size);
-	if (!num || vp_ioread16(&cfg->queue_enable))
+	if (!num || vp_modern_get_queue_enable(mdev, index))
 		return ERR_PTR(-ENOENT);
 
 	if (num & (num - 1)) {
@@ -538,7 +566,6 @@ static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			      struct irq_affinity *desc)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
-	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->mdev.common;
 	struct virtqueue *vq;
 	int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names, ctx, desc);
 
@@ -548,10 +575,8 @@ static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 	/* Select and activate all queues. Has to be done last: once we do
 	 * this, there's no way to go back except reset.
 	 */
-	list_for_each_entry(vq, &vdev->vqs, list) {
-		vp_iowrite16(vq->index, &cfg->queue_select);
-		vp_iowrite16(1, &cfg->queue_enable);
-	}
+	list_for_each_entry(vq, &vdev->vqs, list)
+		vp_modern_set_queue_enable(&vp_dev->mdev, vq->index, true);
 
 	return 0;
 }