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Commit 3beee86a authored by Sjur Brændeland's avatar Sjur Brændeland Committed by Rusty Russell
Browse files

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: default avatarSjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (constified vringh_config)
parent 1515c5ce

include/linux/virtio.h

+3 −0
Original line number Diff line number Diff line
@@ -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 @@ static inline unsigned int virtqueue_get_queue_index(struct virtqueue *vq) 
 * @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 virtio_device { 
	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];

include/linux/vringh.h

+29 −0
Original line number Diff line number Diff line
@@ -47,6 +47,28 @@ struct vringh { 


	/* 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 @@ 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 */