From: Sjur Brændeland <sjur.brandeland@xxxxxxxxxxxxxx>
Add wrappers for the host vrings to support loose
coupling between the virtio device and driver.
The functions find_vrhs() and del_vrhs() are added to
struct virtio_config_ops to manage the host vrings.
The function vringh_notify() is added so the guest
can be kicked when buffers are added to the used-ring.
This enables the virtio drivers to manage the virtio rings
without knowledge of how the host vrings are managed.
Cc: Ohad Ben-Cohen <ohad@xxxxxxxxxx>
Signed-off-by: Sjur Brændeland <sjur.brandeland@xxxxxxxxxxxxxx>
---
include/linux/virtio_config.h | 13 +++++++++++++
include/linux/vringh.h | 13 +++++++++++++
2 files changed, 26 insertions(+), 0 deletions(-)
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 29b9104..88dd5ae 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -51,7 +51,17 @@
* This returns a pointer to the bus name a la pci_name from which
* the caller can then copy.
* @set_vq_affinity: set the affinity for a virtqueue.
+ * @find_vrhs: find the host vrings and instantiate them
+ * vdev: the virtio_device
+ * nhvrs: the number of host vrings to find
+ * hvrs: on success, includes new host vrings
+ * callbacks: array of driver callbacks, for each host vring
+ * include a NULL entry for vqs that do not need a callback
+ * Returns 0 on success or error status
+ * @del_vrhs: free the host vrings found by find_vrhs().
*/
+struct vringh;
+typedef void vrh_callback_t(struct virtio_device *, struct vringh *);
typedef void vq_callback_t(struct virtqueue *);
struct virtio_config_ops {
void (*get)(struct virtio_device *vdev, unsigned offset,
@@ -70,6 +80,9 @@ struct virtio_config_ops {
void (*finalize_features)(struct virtio_device *vdev);
const char *(*bus_name)(struct virtio_device *vdev);
int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
+ int (*find_vrhs)(struct virtio_device *vdev, unsigned nhvrs,
+ struct vringh *vrhs[], vrh_callback_t *callbacks[]);
+ void (*del_vrhs)(struct virtio_device *vdev);
};
/* If driver didn't advertise the feature, it will never appear. */
diff --git a/include/linux/vringh.h b/include/linux/vringh.h
index ab41185..8156f51 100644
--- a/include/linux/vringh.h
+++ b/include/linux/vringh.h
@@ -50,6 +50,12 @@ struct vringh {
/* The vring (note: it may contain user pointers!) */
struct vring vring;
+
+ /* The function to call when buffers are available */
+ void (*notify)(struct vringh *);
+
+ /* A pointer for the vringh clients to use. */
+ void *priv;
};
/* The memory the vring can access, and what offset to apply. */
@@ -182,4 +188,11 @@ void vringh_notify_disable_kern(struct vringh *vrh);
int vringh_need_notify_kern(struct vringh *vrh);
+/* Notify the guest about buffers added to the used ring */
+static inline void vringh_notify(struct vringh *vrh)
+{
+ if (vrh->notify)
+ vrh->notify(vrh);
+}
+
#endif /* _LINUX_VRINGH_H */
--
1.7.5.4
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