/* 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 <[email protected]> */ #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/spinlock.h> #if IS_REACHABLE(CONFIG_VHOST_IOTLB) #include <linux/dma-direction.h> #include <linux/vhost_iotlb.h> #endif #include <asm/barrier.h> /* virtio_ring with information needed for host access. */ struct vringh { … }; struct virtio_device; vrh_callback_t; /** * 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 vringh_config_ops { … }; /* The memory the vring can access, and what offset to apply. */ struct vringh_range { … }; /** * struct vringh_iov - iovec mangler. * @iov: array of iovecs to operate on * @consumed: number of bytes consumed within iov[i] * @i: index of current iovec * @used: number of iovecs present in @iov * @max_num: maximum number of iovecs. * corresponds to allocated memory of @iov * * Mangles iovec in place, and restores it. * Remaining data is iov + i, of used - i elements. */ struct vringh_iov { … }; /** * struct vringh_kiov - kvec mangler. * @iov: array of iovecs to operate on * @consumed: number of bytes consumed within iov[i] * @i: index of current iovec * @used: number of iovecs present in @iov * @max_num: maximum number of iovecs. * corresponds to allocated memory of @iov * * Mangles kvec in place, and restores it. * Remaining data is iov + i, of used - i elements. */ struct vringh_kiov { … }; /* Flag on max_num to indicate we're kmalloced. */ #define VRINGH_IOV_ALLOCATED … /* Helpers for userspace vrings. */ int vringh_init_user(struct vringh *vrh, u64 features, unsigned int num, bool weak_barriers, vring_desc_t __user *desc, vring_avail_t __user *avail, vring_used_t __user *used); static inline void vringh_iov_init(struct vringh_iov *iov, struct iovec *iovec, unsigned num) { … } static inline void vringh_iov_reset(struct vringh_iov *iov) { … } static inline void vringh_iov_cleanup(struct vringh_iov *iov) { … } /* 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) { … } static inline void vringh_kiov_reset(struct vringh_kiov *kiov) { … } static inline void vringh_kiov_cleanup(struct vringh_kiov *kiov) { … } static inline size_t vringh_kiov_length(struct vringh_kiov *kiov) { … } void vringh_kiov_advance(struct vringh_kiov *kiov, size_t len); 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) { … } static inline bool vringh_is_little_endian(const struct vringh *vrh) { … } static inline u16 vringh16_to_cpu(const struct vringh *vrh, __virtio16 val) { … } static inline __virtio16 cpu_to_vringh16(const struct vringh *vrh, u16 val) { … } static inline u32 vringh32_to_cpu(const struct vringh *vrh, __virtio32 val) { … } static inline __virtio32 cpu_to_vringh32(const struct vringh *vrh, u32 val) { … } static inline u64 vringh64_to_cpu(const struct vringh *vrh, __virtio64 val) { … } static inline __virtio64 cpu_to_vringh64(const struct vringh *vrh, u64 val) { … } #if IS_REACHABLE(CONFIG_VHOST_IOTLB) void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb, spinlock_t *iotlb_lock); 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_init_iotlb_va(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 /* CONFIG_VHOST_IOTLB */ #endif /* _LINUX_VRINGH_H */
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