virtio: Introduce vringh wrappers in virtio_config
Add wrappers for the host vrings to support loose
coupling between the virtio device and driver.
A new struct vringh_config_ops with the functions
find_vrhs() and del_vrhs() is added to the virtio_device
struct. This enables virtio drivers to manage virtio
host rings without detailed knowledge of how the
vrings are created and deleted.
The function vringh_notify() is added so vringh clients
can notify the other side that buffers are added to the
used-ring.
Cc: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (constified vringh_config)
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index ff6714e..5d5b3ab 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -8,6 +8,7 @@
#include <linux/device.h>
#include <linux/mod_devicetable.h>
#include <linux/gfp.h>
+#include <linux/vringh.h>
/**
* virtqueue - a queue to register buffers for sending or receiving.
@@ -70,6 +71,7 @@
* @dev: underlying device.
* @id: the device type identification (used to match it with a driver).
* @config: the configuration ops for this device.
+ * @vringh_config: configuration ops for host vrings.
* @vqs: the list of virtqueues for this device.
* @features: the features supported by both driver and device.
* @priv: private pointer for the driver's use.
@@ -79,6 +81,7 @@
struct device dev;
struct virtio_device_id id;
const struct virtio_config_ops *config;
+ const struct vringh_config_ops *vringh_config;
struct list_head vqs;
/* Note that this is a Linux set_bit-style bitmap. */
unsigned long features[1];
diff --git a/include/linux/vringh.h b/include/linux/vringh.h
index b8f0866..749cde2 100644
--- a/include/linux/vringh.h
+++ b/include/linux/vringh.h
@@ -47,6 +47,28 @@
/* The vring (note: it may contain user pointers!) */
struct vring vring;
+
+ /* The function to call to notify the guest about added buffers */
+ void (*notify)(struct vringh *);
+};
+
+/**
+ * struct vringh_config_ops - ops for creating a host vring from a virtio driver
+ * @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 virtio_device;
+typedef void vrh_callback_t(struct virtio_device *, struct vringh *);
+struct vringh_config_ops {
+ int (*find_vrhs)(struct virtio_device *vdev, unsigned nhvrs,
+ struct vringh *vrhs[], vrh_callback_t *callbacks[]);
+ void (*del_vrhs)(struct virtio_device *vdev);
};
/* The memory the vring can access, and what offset to apply. */
@@ -193,4 +215,11 @@
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 */