vdpa: introduce get_vq_notification method

This patch introduces a new method in the vdpa_config_ops which
reports the physical address and the size of the doorbell for a
specific virtqueue.

This will be used by the future patches that maps doorbell to
userspace.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20200529080303.15449-4-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 5453af8..239db79 100644 (file)
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -18,6 +18,16 @@ struct vdpa_callback {
 };
 
 /**
+ * vDPA notification area
+ * @addr: base address of the notification area
+ * @size: size of the notification area
+ */
+struct vdpa_notification_area {
+       resource_size_t addr;
+       resource_size_t size;
+};
+
+/**
  * vDPA device - representation of a vDPA device
  * @dev: underlying device
  * @dma_dev: the actual device that is performing DMA
@@ -73,6 +83,10 @@ struct vdpa_device {
  *                             @vdev: vdpa device
  *                             @idx: virtqueue index
  *                             Returns virtqueue state (last_avail_idx)
+ * @get_vq_notification:       Get the notification area for a virtqueue
+ *                             @vdev: vdpa device
+ *                             @idx: virtqueue index
+ *                             Returns the notifcation area
  * @get_vq_align:              Get the virtqueue align requirement
  *                             for the device
  *                             @vdev: vdpa device
@@ -162,6 +176,8 @@ struct vdpa_config_ops {
        bool (*get_vq_ready)(struct vdpa_device *vdev, u16 idx);
        int (*set_vq_state)(struct vdpa_device *vdev, u16 idx, u64 state);
        u64 (*get_vq_state)(struct vdpa_device *vdev, u16 idx);
+       struct vdpa_notification_area
+       (*get_vq_notification)(struct vdpa_device *vdev, u16 idx);
 
        /* Device ops */
        u32 (*get_vq_align)(struct vdpa_device *vdev);