[03/19] virtio: Add get_shm_region method

Commit Message

Vivek Goyal Aug. 21, 2019, 5:57 p.m. UTC

From: Sebastien Boeuf <[e-mail]>

Virtio defines 'shared memory regions' that provide a continuously
shared region between the host and guest.

Provide a method to find a particular region on a device.

Signed-off-by: Sebastien Boeuf <[e-mail]>
Signed-off-by: Dr. David Alan Gilbert <[e-mail]>
---
 include/linux/virtio_config.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

Patch

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index bb4cc4910750..c859f000a751 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -10,6 +10,11 @@ 
 
 struct irq_affinity;
 
+struct virtio_shm_region {
+       u64 addr;
+       u64 len;
+};
+
 /**
  * virtio_config_ops - operations for configuring a virtio device
  * Note: Do not assume that a transport implements all of the operations
@@ -65,6 +70,7 @@  struct irq_affinity;
  *      the caller can then copy.
  * @set_vq_affinity: set the affinity for a virtqueue (optional).
  * @get_vq_affinity: get the affinity for a virtqueue (optional).
+ * @get_shm_region: get a shared memory region based on the index.
  */
 typedef void vq_callback_t(struct virtqueue *);
 struct virtio_config_ops {
@@ -88,6 +94,8 @@  struct virtio_config_ops {
 			       const struct cpumask *cpu_mask);
 	const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
 			int index);
+	bool (*get_shm_region)(struct virtio_device *vdev,
+			       struct virtio_shm_region *region, u8 id);
 };
 
 /* If driver didn't advertise the feature, it will never appear. */
@@ -250,6 +258,15 @@  int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
 	return 0;
 }
 
+static inline
+bool virtio_get_shm_region(struct virtio_device *vdev,
+                         struct virtio_shm_region *region, u8 id)
+{
+	if (!vdev->config->get_shm_region)
+		return false;
+	return vdev->config->get_shm_region(vdev, region, id);
+}
+
 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
 {
 	return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||