[linux-block.git] / include / linux / vringh.h

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Linux host-side vring helpers; for when the kernel needs to access
 * someone else's vring.
 *
 * Copyright IBM Corporation, 2013.
 * Parts taken from drivers/vhost/vhost.c Copyright 2009 Red Hat, Inc.
 *
 * Written by: Rusty Russell <rusty@rustcorp.com.au>
 */
#ifndef _LINUX_VRINGH_H
#define _LINUX_VRINGH_H
#include <uapi/linux/virtio_ring.h>
#include <linux/virtio_byteorder.h>
#include <linux/uio.h>
#include <linux/slab.h>
#include <linux/dma-direction.h>
#include <linux/vhost_iotlb.h>
#include <asm/barrier.h>

/* virtio_ring with information needed for host access. */
struct vringh {
	/* Everything is little endian */
	bool little_endian;

	/* Guest publishes used event idx (note: we always do). */
	bool event_indices;

	/* Can we get away with weak barriers? */
	bool weak_barriers;

	/* Last available index we saw (ie. where we're up to). */
	u16 last_avail_idx;

	/* Last index we used. */
	u16 last_used_idx;

	/* How many descriptors we've completed since last need_notify(). */
	u32 completed;

	/* The vring (note: it may contain user pointers!) */
	struct vring vring;

	/* IOTLB for this vring */
	struct vhost_iotlb *iotlb;

	/* 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. */
struct vringh_range {
	u64 start, end_incl;
	u64 offset;
};

/**
 * struct vringh_iov - iovec mangler.
 *
 * Mangles iovec in place, and restores it.
 * Remaining data is iov + i, of used - i elements.
 */
struct vringh_iov {
	struct iovec *iov;
	size_t consumed; /* Within iov[i] */
	unsigned i, used, max_num;
};

/**
 * struct vringh_iov - kvec mangler.
 *
 * Mangles kvec in place, and restores it.
 * Remaining data is iov + i, of used - i elements.
 */
struct vringh_kiov {
	struct kvec *iov;
	size_t consumed; /* Within iov[i] */
	unsigned i, used, max_num;
};

/* Flag on max_num to indicate we're kmalloced. */
#define VRINGH_IOV_ALLOCATED 0x8000000

/* Helpers for userspace vrings. */
int vringh_init_user(struct vringh *vrh, u64 features,
		     unsigned int num, bool weak_barriers,
		     struct vring_desc __user *desc,
		     struct vring_avail __user *avail,
		     struct vring_used __user *used);

static inline void vringh_iov_init(struct vringh_iov *iov,
				   struct iovec *iovec, unsigned num)
{
	iov->used = iov->i = 0;
	iov->consumed = 0;
	iov->max_num = num;
	iov->iov = iovec;
}

static inline void vringh_iov_reset(struct vringh_iov *iov)
{
	iov->iov[iov->i].iov_len += iov->consumed;
	iov->iov[iov->i].iov_base -= iov->consumed;
	iov->consumed = 0;
	iov->i = 0;
}

static inline void vringh_iov_cleanup(struct vringh_iov *iov)
{
	if (iov->max_num & VRINGH_IOV_ALLOCATED)
		kfree(iov->iov);
	iov->max_num = iov->used = iov->i = iov->consumed = 0;
	iov->iov = NULL;
}

/* Convert a descriptor into iovecs. */
int vringh_getdesc_user(struct vringh *vrh,
			struct vringh_iov *riov,
			struct vringh_iov *wiov,
			bool (*getrange)(struct vringh *vrh,
					 u64 addr, struct vringh_range *r),
			u16 *head);

/* Copy bytes from readable vsg, consuming it (and incrementing wiov->i). */
ssize_t vringh_iov_pull_user(struct vringh_iov *riov, void *dst, size_t len);

/* Copy bytes into writable vsg, consuming it (and incrementing wiov->i). */
ssize_t vringh_iov_push_user(struct vringh_iov *wiov,
			     const void *src, size_t len);

/* Mark a descriptor as used. */
int vringh_complete_user(struct vringh *vrh, u16 head, u32 len);
int vringh_complete_multi_user(struct vringh *vrh,
			       const struct vring_used_elem used[],
			       unsigned num_used);

/* Pretend we've never seen descriptor (for easy error handling). */
void vringh_abandon_user(struct vringh *vrh, unsigned int num);

/* Do we need to fire the eventfd to notify the other side? */
int vringh_need_notify_user(struct vringh *vrh);

bool vringh_notify_enable_user(struct vringh *vrh);
void vringh_notify_disable_user(struct vringh *vrh);

/* Helpers for kernelspace vrings. */
int vringh_init_kern(struct vringh *vrh, u64 features,
		     unsigned int num, bool weak_barriers,
		     struct vring_desc *desc,
		     struct vring_avail *avail,
		     struct vring_used *used);

static inline void vringh_kiov_init(struct vringh_kiov *kiov,
				    struct kvec *kvec, unsigned num)
{
	kiov->used = kiov->i = 0;
	kiov->consumed = 0;
	kiov->max_num = num;
	kiov->iov = kvec;
}

static inline void vringh_kiov_reset(struct vringh_kiov *kiov)
{
	kiov->iov[kiov->i].iov_len += kiov->consumed;
	kiov->iov[kiov->i].iov_base -= kiov->consumed;
	kiov->consumed = 0;
	kiov->i = 0;
}

static inline void vringh_kiov_cleanup(struct vringh_kiov *kiov)
{
	if (kiov->max_num & VRINGH_IOV_ALLOCATED)
		kfree(kiov->iov);
	kiov->max_num = kiov->used = kiov->i = kiov->consumed = 0;
	kiov->iov = NULL;
}

int vringh_getdesc_kern(struct vringh *vrh,
			struct vringh_kiov *riov,
			struct vringh_kiov *wiov,
			u16 *head,
			gfp_t gfp);

ssize_t vringh_iov_pull_kern(struct vringh_kiov *riov, void *dst, size_t len);
ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov,
			     const void *src, size_t len);
void vringh_abandon_kern(struct vringh *vrh, unsigned int num);
int vringh_complete_kern(struct vringh *vrh, u16 head, u32 len);

bool vringh_notify_enable_kern(struct vringh *vrh);
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);
}

static inline bool vringh_is_little_endian(const struct vringh *vrh)
{
	return vrh->little_endian ||
		virtio_legacy_is_little_endian();
}

static inline u16 vringh16_to_cpu(const struct vringh *vrh, __virtio16 val)
{
	return __virtio16_to_cpu(vringh_is_little_endian(vrh), val);
}

static inline __virtio16 cpu_to_vringh16(const struct vringh *vrh, u16 val)
{
	return __cpu_to_virtio16(vringh_is_little_endian(vrh), val);
}

static inline u32 vringh32_to_cpu(const struct vringh *vrh, __virtio32 val)
{
	return __virtio32_to_cpu(vringh_is_little_endian(vrh), val);
}

static inline __virtio32 cpu_to_vringh32(const struct vringh *vrh, u32 val)
{
	return __cpu_to_virtio32(vringh_is_little_endian(vrh), val);
}

static inline u64 vringh64_to_cpu(const struct vringh *vrh, __virtio64 val)
{
	return __virtio64_to_cpu(vringh_is_little_endian(vrh), val);
}

static inline __virtio64 cpu_to_vringh64(const struct vringh *vrh, u64 val)
{
	return __cpu_to_virtio64(vringh_is_little_endian(vrh), val);
}

void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb);

int vringh_init_iotlb(struct vringh *vrh, u64 features,
		      unsigned int num, bool weak_barriers,
		      struct vring_desc *desc,
		      struct vring_avail *avail,
		      struct vring_used *used);

int vringh_getdesc_iotlb(struct vringh *vrh,
			 struct vringh_kiov *riov,
			 struct vringh_kiov *wiov,
			 u16 *head,
			 gfp_t gfp);

ssize_t vringh_iov_pull_iotlb(struct vringh *vrh,
			      struct vringh_kiov *riov,
			      void *dst, size_t len);
ssize_t vringh_iov_push_iotlb(struct vringh *vrh,
			      struct vringh_kiov *wiov,
			      const void *src, size_t len);

void vringh_abandon_iotlb(struct vringh *vrh, unsigned int num);

int vringh_complete_iotlb(struct vringh *vrh, u16 head, u32 len);

bool vringh_notify_enable_iotlb(struct vringh *vrh);
void vringh_notify_disable_iotlb(struct vringh *vrh);

int vringh_need_notify_iotlb(struct vringh *vrh);

#endif /* _LINUX_VRINGH_H */
Commit	Line	Data
1a59d1b8	1	/* SPDX-License-Identifier: GPL-2.0-or-later */
f87d0fbb RR	2	/*
	3	* Linux host-side vring helpers; for when the kernel needs to access
	4	* someone else's vring.
	5	*
	6	* Copyright IBM Corporation, 2013.
	7	* Parts taken from drivers/vhost/vhost.c Copyright 2009 Red Hat, Inc.
	8	*
f87d0fbb RR	9	* Written by: Rusty Russell <rusty@rustcorp.com.au>
	10	*/
	11	#ifndef _LINUX_VRINGH_H
	12	#define _LINUX_VRINGH_H
	13	#include <uapi/linux/virtio_ring.h>
b9f7ac8c	14	#include <linux/virtio_byteorder.h>
f87d0fbb RR	15	#include <linux/uio.h>
f87d0fbb RR	16	#include <linux/slab.h>
9ad9c49c JW	17	#include <linux/dma-direction.h>
9ad9c49c JW	18	#include <linux/vhost_iotlb.h>
f87d0fbb RR	19	#include <asm/barrier.h>
	20
	21	/* virtio_ring with information needed for host access. */
	22	struct vringh {
b9f7ac8c MT	23	/* Everything is little endian */
	24	bool little_endian;
	25
f87d0fbb RR	26	/* Guest publishes used event idx (note: we always do). */
	27	bool event_indices;
	28
	29	/* Can we get away with weak barriers? */
	30	bool weak_barriers;
	31
	32	/* Last available index we saw (ie. where we're up to). */
	33	u16 last_avail_idx;
	34
	35	/* Last index we used. */
	36	u16 last_used_idx;
	37
	38	/* How many descriptors we've completed since last need_notify(). */
	39	u32 completed;
	40
	41	/* The vring (note: it may contain user pointers!) */
	42	struct vring vring;
3beee86a	43
9ad9c49c JW	44	/* IOTLB for this vring */
	45	struct vhost_iotlb *iotlb;
	46
3beee86a SB	47	/* The function to call to notify the guest about added buffers */
	48	void (notify)(struct vringh );
	49	};
	50
	51	/**
	52	* struct vringh_config_ops - ops for creating a host vring from a virtio driver
	53	* @find_vrhs: find the host vrings and instantiate them
	54	* vdev: the virtio_device
	55	* nhvrs: the number of host vrings to find
	56	* hvrs: on success, includes new host vrings
	57	* callbacks: array of driver callbacks, for each host vring
	58	* include a NULL entry for vqs that do not need a callback
	59	* Returns 0 on success or error status
	60	* @del_vrhs: free the host vrings found by find_vrhs().
	61	*/
	62	struct virtio_device;
	63	typedef void vrh_callback_t(struct virtio_device , struct vringh );
	64	struct vringh_config_ops {
	65	int (find_vrhs)(struct virtio_device vdev, unsigned nhvrs,
	66	struct vringh vrhs[], vrh_callback_t callbacks[]);
	67	void (del_vrhs)(struct virtio_device vdev);
f87d0fbb RR	68	};
	69
	70	/* The memory the vring can access, and what offset to apply. */
	71	struct vringh_range {
	72	u64 start, end_incl;
	73	u64 offset;
	74	};
	75
	76	/**
	77	* struct vringh_iov - iovec mangler.
	78	*
	79	* Mangles iovec in place, and restores it.
	80	* Remaining data is iov + i, of used - i elements.
	81	*/
	82	struct vringh_iov {
	83	struct iovec *iov;
	84	size_t consumed; /* Within iov[i] */
	85	unsigned i, used, max_num;
	86	};
	87
	88	/**
	89	* struct vringh_iov - kvec mangler.
	90	*
	91	* Mangles kvec in place, and restores it.
	92	* Remaining data is iov + i, of used - i elements.
	93	*/
	94	struct vringh_kiov {
	95	struct kvec *iov;
	96	size_t consumed; /* Within iov[i] */
	97	unsigned i, used, max_num;
	98	};
	99
	100	/* Flag on max_num to indicate we're kmalloced. */
	101	#define VRINGH_IOV_ALLOCATED 0x8000000
	102
	103	/* Helpers for userspace vrings. */
b97a8a90	104	int vringh_init_user(struct vringh *vrh, u64 features,
f87d0fbb RR	105	unsigned int num, bool weak_barriers,
	106	struct vring_desc __user *desc,
	107	struct vring_avail __user *avail,
	108	struct vring_used __user *used);
	109
	110	static inline void vringh_iov_init(struct vringh_iov *iov,
	111	struct iovec *iovec, unsigned num)
	112	{
	113	iov->used = iov->i = 0;
	114	iov->consumed = 0;
	115	iov->max_num = num;
	116	iov->iov = iovec;
	117	}
	118
	119	static inline void vringh_iov_reset(struct vringh_iov *iov)
	120	{
	121	iov->iov[iov->i].iov_len += iov->consumed;
	122	iov->iov[iov->i].iov_base -= iov->consumed;
	123	iov->consumed = 0;
	124	iov->i = 0;
	125	}
	126
	127	static inline void vringh_iov_cleanup(struct vringh_iov *iov)
	128	{
	129	if (iov->max_num & VRINGH_IOV_ALLOCATED)
	130	kfree(iov->iov);
	131	iov->max_num = iov->used = iov->i = iov->consumed = 0;
	132	iov->iov = NULL;
	133	}
	134
	135	/* Convert a descriptor into iovecs. */
	136	int vringh_getdesc_user(struct vringh *vrh,
	137	struct vringh_iov *riov,
	138	struct vringh_iov *wiov,
	139	bool (getrange)(struct vringh vrh,
	140	u64 addr, struct vringh_range *r),
	141	u16 *head);
	142
	143	/* Copy bytes from readable vsg, consuming it (and incrementing wiov->i). */
	144	ssize_t vringh_iov_pull_user(struct vringh_iov riov, void dst, size_t len);
	145
	146	/* Copy bytes into writable vsg, consuming it (and incrementing wiov->i). */
	147	ssize_t vringh_iov_push_user(struct vringh_iov *wiov,
	148	const void *src, size_t len);
	149
	150	/* Mark a descriptor as used. */
	151	int vringh_complete_user(struct vringh *vrh, u16 head, u32 len);
	152	int vringh_complete_multi_user(struct vringh *vrh,
	153	const struct vring_used_elem used[],
	154	unsigned num_used);
	155
	156	/* Pretend we've never seen descriptor (for easy error handling). */
	157	void vringh_abandon_user(struct vringh *vrh, unsigned int num);
	158
	159	/* Do we need to fire the eventfd to notify the other side? */
	160	int vringh_need_notify_user(struct vringh *vrh);
	161
	162	bool vringh_notify_enable_user(struct vringh *vrh);
	163	void vringh_notify_disable_user(struct vringh *vrh);
	164
	165	/* Helpers for kernelspace vrings. */
b97a8a90	166	int vringh_init_kern(struct vringh *vrh, u64 features,
f87d0fbb RR	167	unsigned int num, bool weak_barriers,
	168	struct vring_desc *desc,
	169	struct vring_avail *avail,
	170	struct vring_used *used);
	171
	172	static inline void vringh_kiov_init(struct vringh_kiov *kiov,
	173	struct kvec *kvec, unsigned num)
	174	{
	175	kiov->used = kiov->i = 0;
	176	kiov->consumed = 0;
	177	kiov->max_num = num;
	178	kiov->iov = kvec;
	179	}
	180
	181	static inline void vringh_kiov_reset(struct vringh_kiov *kiov)
	182	{
	183	kiov->iov[kiov->i].iov_len += kiov->consumed;
	184	kiov->iov[kiov->i].iov_base -= kiov->consumed;
	185	kiov->consumed = 0;
	186	kiov->i = 0;
	187	}
	188
	189	static inline void vringh_kiov_cleanup(struct vringh_kiov *kiov)
	190	{
	191	if (kiov->max_num & VRINGH_IOV_ALLOCATED)
	192	kfree(kiov->iov);
	193	kiov->max_num = kiov->used = kiov->i = kiov->consumed = 0;
	194	kiov->iov = NULL;
	195	}
	196
	197	int vringh_getdesc_kern(struct vringh *vrh,
	198	struct vringh_kiov *riov,
	199	struct vringh_kiov *wiov,
	200	u16 *head,
	201	gfp_t gfp);
	202
	203	ssize_t vringh_iov_pull_kern(struct vringh_kiov riov, void dst, size_t len);
	204	ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov,
	205	const void *src, size_t len);
	206	void vringh_abandon_kern(struct vringh *vrh, unsigned int num);
	207	int vringh_complete_kern(struct vringh *vrh, u16 head, u32 len);
	208
	209	bool vringh_notify_enable_kern(struct vringh *vrh);
	210	void vringh_notify_disable_kern(struct vringh *vrh);
	211
	212	int vringh_need_notify_kern(struct vringh *vrh);
	213
3beee86a SB	214	/* Notify the guest about buffers added to the used ring */
	215	static inline void vringh_notify(struct vringh *vrh)
	216	{
	217	if (vrh->notify)
	218	vrh->notify(vrh);
	219	}
	220
5da7b160 GK	221	static inline bool vringh_is_little_endian(const struct vringh *vrh)
5da7b160 GK	222	{
7d824109 GK	223	return vrh->little_endian \|\|
7d824109 GK	224	virtio_legacy_is_little_endian();
5da7b160 GK	225	}
5da7b160 GK	226
b9f7ac8c MT	227	static inline u16 vringh16_to_cpu(const struct vringh *vrh, __virtio16 val)
b9f7ac8c MT	228	{
5da7b160	229	return __virtio16_to_cpu(vringh_is_little_endian(vrh), val);
b9f7ac8c MT	230	}
	231
	232	static inline __virtio16 cpu_to_vringh16(const struct vringh *vrh, u16 val)
	233	{
5da7b160	234	return __cpu_to_virtio16(vringh_is_little_endian(vrh), val);
b9f7ac8c MT	235	}
	236
	237	static inline u32 vringh32_to_cpu(const struct vringh *vrh, __virtio32 val)
	238	{
5da7b160	239	return __virtio32_to_cpu(vringh_is_little_endian(vrh), val);
b9f7ac8c MT	240	}
	241
	242	static inline __virtio32 cpu_to_vringh32(const struct vringh *vrh, u32 val)
	243	{
5da7b160	244	return __cpu_to_virtio32(vringh_is_little_endian(vrh), val);
b9f7ac8c MT	245	}
	246
	247	static inline u64 vringh64_to_cpu(const struct vringh *vrh, __virtio64 val)
	248	{
5da7b160	249	return __virtio64_to_cpu(vringh_is_little_endian(vrh), val);
b9f7ac8c MT	250	}
	251
	252	static inline __virtio64 cpu_to_vringh64(const struct vringh *vrh, u64 val)
	253	{
5da7b160	254	return __cpu_to_virtio64(vringh_is_little_endian(vrh), val);
b9f7ac8c	255	}
9ad9c49c JW	256
	257	void vringh_set_iotlb(struct vringh vrh, struct vhost_iotlb iotlb);
	258
	259	int vringh_init_iotlb(struct vringh *vrh, u64 features,
	260	unsigned int num, bool weak_barriers,
	261	struct vring_desc *desc,
	262	struct vring_avail *avail,
	263	struct vring_used *used);
	264
	265	int vringh_getdesc_iotlb(struct vringh *vrh,
	266	struct vringh_kiov *riov,
	267	struct vringh_kiov *wiov,
	268	u16 *head,
	269	gfp_t gfp);
	270
	271	ssize_t vringh_iov_pull_iotlb(struct vringh *vrh,
	272	struct vringh_kiov *riov,
	273	void *dst, size_t len);
	274	ssize_t vringh_iov_push_iotlb(struct vringh *vrh,
	275	struct vringh_kiov *wiov,
	276	const void *src, size_t len);
	277
	278	void vringh_abandon_iotlb(struct vringh *vrh, unsigned int num);
	279
	280	int vringh_complete_iotlb(struct vringh *vrh, u16 head, u32 len);
	281
	282	bool vringh_notify_enable_iotlb(struct vringh *vrh);
	283	void vringh_notify_disable_iotlb(struct vringh *vrh);
	284
	285	int vringh_need_notify_iotlb(struct vringh *vrh);
	286
f87d0fbb	287	#endif /* _LINUX_VRINGH_H */