diff options
Diffstat (limited to 'drivers/vhost/vringh.c')
| -rw-r--r-- | drivers/vhost/vringh.c | 421 |
1 files changed, 398 insertions, 23 deletions
diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index a0a2d74967ef..ee0491f579ac 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -13,6 +13,9 @@ #include <linux/uaccess.h> #include <linux/slab.h> #include <linux/export.h> +#include <linux/bvec.h> +#include <linux/highmem.h> +#include <linux/vhost_iotlb.h> #include <uapi/linux/virtio_config.h> static __printf(1,2) __cold void vringh_bad(const char *fmt, ...) @@ -71,9 +74,11 @@ static inline int __vringh_get_head(const struct vringh *vrh, } /* Copy some bytes to/from the iovec. Returns num copied. */ -static inline ssize_t vringh_iov_xfer(struct vringh_kiov *iov, +static inline ssize_t vringh_iov_xfer(struct vringh *vrh, + struct vringh_kiov *iov, void *ptr, size_t len, - int (*xfer)(void *addr, void *ptr, + int (*xfer)(const struct vringh *vrh, + void *addr, void *ptr, size_t len)) { int err, done = 0; @@ -82,7 +87,7 @@ static inline ssize_t vringh_iov_xfer(struct vringh_kiov *iov, size_t partlen; partlen = min(iov->iov[iov->i].iov_len, len); - err = xfer(iov->iov[iov->i].iov_base, ptr, partlen); + err = xfer(vrh, iov->iov[iov->i].iov_base, ptr, partlen); if (err) return err; done += partlen; @@ -96,6 +101,7 @@ static inline ssize_t vringh_iov_xfer(struct vringh_kiov *iov, /* Fix up old iov element then increment. */ iov->iov[iov->i].iov_len = iov->consumed; iov->iov[iov->i].iov_base -= iov->consumed; + iov->consumed = 0; iov->i++; @@ -227,7 +233,8 @@ static int slow_copy(struct vringh *vrh, void *dst, const void *src, u64 addr, struct vringh_range *r), struct vringh_range *range, - int (*copy)(void *dst, const void *src, size_t len)) + int (*copy)(const struct vringh *vrh, + void *dst, const void *src, size_t len)) { size_t part, len = sizeof(struct vring_desc); @@ -241,7 +248,7 @@ static int slow_copy(struct vringh *vrh, void *dst, const void *src, if (!rcheck(vrh, addr, &part, range, getrange)) return -EINVAL; - err = copy(dst, src, part); + err = copy(vrh, dst, src, part); if (err) return err; @@ -262,7 +269,8 @@ __vringh_iov(struct vringh *vrh, u16 i, struct vringh_range *)), bool (*getrange)(struct vringh *, u64, struct vringh_range *), gfp_t gfp, - int (*copy)(void *dst, const void *src, size_t len)) + int (*copy)(const struct vringh *vrh, + void *dst, const void *src, size_t len)) { int err, count = 0, up_next, desc_max; struct vring_desc desc, *descs; @@ -291,7 +299,7 @@ __vringh_iov(struct vringh *vrh, u16 i, err = slow_copy(vrh, &desc, &descs[i], rcheck, getrange, &slowrange, copy); else - err = copy(&desc, &descs[i], sizeof(desc)); + err = copy(vrh, &desc, &descs[i], sizeof(desc)); if (unlikely(err)) goto fail; @@ -404,7 +412,8 @@ static inline int __vringh_complete(struct vringh *vrh, unsigned int num_used, int (*putu16)(const struct vringh *vrh, __virtio16 *p, u16 val), - int (*putused)(struct vring_used_elem *dst, + int (*putused)(const struct vringh *vrh, + struct vring_used_elem *dst, const struct vring_used_elem *src, unsigned num)) { @@ -420,12 +429,12 @@ static inline int __vringh_complete(struct vringh *vrh, /* Compiler knows num_used == 1 sometimes, hence extra check */ if (num_used > 1 && unlikely(off + num_used >= vrh->vring.num)) { u16 part = vrh->vring.num - off; - err = putused(&used_ring->ring[off], used, part); + err = putused(vrh, &used_ring->ring[off], used, part); if (!err) - err = putused(&used_ring->ring[0], used + part, + err = putused(vrh, &used_ring->ring[0], used + part, num_used - part); } else - err = putused(&used_ring->ring[off], used, num_used); + err = putused(vrh, &used_ring->ring[off], used, num_used); if (err) { vringh_bad("Failed to write %u used entries %u at %p", @@ -564,13 +573,15 @@ static inline int putu16_user(const struct vringh *vrh, __virtio16 *p, u16 val) return put_user(v, (__force __virtio16 __user *)p); } -static inline int copydesc_user(void *dst, const void *src, size_t len) +static inline int copydesc_user(const struct vringh *vrh, + void *dst, const void *src, size_t len) { return copy_from_user(dst, (__force void __user *)src, len) ? -EFAULT : 0; } -static inline int putused_user(struct vring_used_elem *dst, +static inline int putused_user(const struct vringh *vrh, + struct vring_used_elem *dst, const struct vring_used_elem *src, unsigned int num) { @@ -578,13 +589,15 @@ static inline int putused_user(struct vring_used_elem *dst, sizeof(*dst) * num) ? -EFAULT : 0; } -static inline int xfer_from_user(void *src, void *dst, size_t len) +static inline int xfer_from_user(const struct vringh *vrh, void *src, + void *dst, size_t len) { return copy_from_user(dst, (__force void __user *)src, len) ? -EFAULT : 0; } -static inline int xfer_to_user(void *dst, void *src, size_t len) +static inline int xfer_to_user(const struct vringh *vrh, + void *dst, void *src, size_t len) { return copy_to_user((__force void __user *)dst, src, len) ? -EFAULT : 0; @@ -706,7 +719,7 @@ EXPORT_SYMBOL(vringh_getdesc_user); */ ssize_t vringh_iov_pull_user(struct vringh_iov *riov, void *dst, size_t len) { - return vringh_iov_xfer((struct vringh_kiov *)riov, + return vringh_iov_xfer(NULL, (struct vringh_kiov *)riov, dst, len, xfer_from_user); } EXPORT_SYMBOL(vringh_iov_pull_user); @@ -722,7 +735,7 @@ EXPORT_SYMBOL(vringh_iov_pull_user); ssize_t vringh_iov_push_user(struct vringh_iov *wiov, const void *src, size_t len) { - return vringh_iov_xfer((struct vringh_kiov *)wiov, + return vringh_iov_xfer(NULL, (struct vringh_kiov *)wiov, (void *)src, len, xfer_to_user); } EXPORT_SYMBOL(vringh_iov_push_user); @@ -832,13 +845,15 @@ static inline int putu16_kern(const struct vringh *vrh, __virtio16 *p, u16 val) return 0; } -static inline int copydesc_kern(void *dst, const void *src, size_t len) +static inline int copydesc_kern(const struct vringh *vrh, + void *dst, const void *src, size_t len) { memcpy(dst, src, len); return 0; } -static inline int putused_kern(struct vring_used_elem *dst, +static inline int putused_kern(const struct vringh *vrh, + struct vring_used_elem *dst, const struct vring_used_elem *src, unsigned int num) { @@ -846,13 +861,15 @@ static inline int putused_kern(struct vring_used_elem *dst, return 0; } -static inline int xfer_kern(void *src, void *dst, size_t len) +static inline int xfer_kern(const struct vringh *vrh, void *src, + void *dst, size_t len) { memcpy(dst, src, len); return 0; } -static inline int kern_xfer(void *dst, void *src, size_t len) +static inline int kern_xfer(const struct vringh *vrh, void *dst, + void *src, size_t len) { memcpy(dst, src, len); return 0; @@ -949,7 +966,7 @@ EXPORT_SYMBOL(vringh_getdesc_kern); */ ssize_t vringh_iov_pull_kern(struct vringh_kiov *riov, void *dst, size_t len) { - return vringh_iov_xfer(riov, dst, len, xfer_kern); + return vringh_iov_xfer(NULL, riov, dst, len, xfer_kern); } EXPORT_SYMBOL(vringh_iov_pull_kern); @@ -964,7 +981,7 @@ EXPORT_SYMBOL(vringh_iov_pull_kern); ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov, const void *src, size_t len) { - return vringh_iov_xfer(wiov, (void *)src, len, kern_xfer); + return vringh_iov_xfer(NULL, wiov, (void *)src, len, kern_xfer); } EXPORT_SYMBOL(vringh_iov_push_kern); @@ -1042,4 +1059,362 @@ int vringh_need_notify_kern(struct vringh *vrh) } EXPORT_SYMBOL(vringh_need_notify_kern); +static int iotlb_translate(const struct vringh *vrh, + u64 addr, u64 len, struct bio_vec iov[], + int iov_size, u32 perm) +{ + struct vhost_iotlb_map *map; + struct vhost_iotlb *iotlb = vrh->iotlb; + int ret = 0; + u64 s = 0; + + while (len > s) { + u64 size, pa, pfn; + + if (unlikely(ret >= iov_size)) { + ret = -ENOBUFS; + break; + } + + map = vhost_iotlb_itree_first(iotlb, addr, + addr + len - 1); + if (!map || map->start > addr) { + ret = -EINVAL; + break; + } else if (!(map->perm & perm)) { + ret = -EPERM; + break; + } + + size = map->size - addr + map->start; + pa = map->addr + addr - map->start; + pfn = pa >> PAGE_SHIFT; + iov[ret].bv_page = pfn_to_page(pfn); + iov[ret].bv_len = min(len - s, size); + iov[ret].bv_offset = pa & (PAGE_SIZE - 1); + s += size; + addr += size; + ++ret; + } + + return ret; +} + +static inline int copy_from_iotlb(const struct vringh *vrh, void *dst, + void *src, size_t len) +{ + struct iov_iter iter; + struct bio_vec iov[16]; + int ret; + + ret = iotlb_translate(vrh, (u64)(uintptr_t)src, + len, iov, 16, VHOST_MAP_RO); + if (ret < 0) + return ret; + + iov_iter_bvec(&iter, READ, iov, ret, len); + + ret = copy_from_iter(dst, len, &iter); + + return ret; +} + +static inline int copy_to_iotlb(const struct vringh *vrh, void *dst, + void *src, size_t len) +{ + struct iov_iter iter; + struct bio_vec iov[16]; + int ret; + + ret = iotlb_translate(vrh, (u64)(uintptr_t)dst, + len, iov, 16, VHOST_MAP_WO); + if (ret < 0) + return ret; + + iov_iter_bvec(&iter, WRITE, iov, ret, len); + + return copy_to_iter(src, len, &iter); +} + +static inline int getu16_iotlb(const struct vringh *vrh, + u16 *val, const __virtio16 *p) +{ + struct bio_vec iov; + void *kaddr, *from; + int ret; + + /* Atomic read is needed for getu16 */ + ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), + &iov, 1, VHOST_MAP_RO); + if (ret < 0) + return ret; + + kaddr = kmap_atomic(iov.bv_page); + from = kaddr + iov.bv_offset; + *val = vringh16_to_cpu(vrh, READ_ONCE(*(__virtio16 *)from)); + kunmap_atomic(kaddr); + + return 0; +} + +static inline int putu16_iotlb(const struct vringh *vrh, + __virtio16 *p, u16 val) +{ + struct bio_vec iov; + void *kaddr, *to; + int ret; + + /* Atomic write is needed for putu16 */ + ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), + &iov, 1, VHOST_MAP_WO); + if (ret < 0) + return ret; + + kaddr = kmap_atomic(iov.bv_page); + to = kaddr + iov.bv_offset; + WRITE_ONCE(*(__virtio16 *)to, cpu_to_vringh16(vrh, val)); + kunmap_atomic(kaddr); + + return 0; +} + +static inline int copydesc_iotlb(const struct vringh *vrh, + void *dst, const void *src, size_t len) +{ + int ret; + + ret = copy_from_iotlb(vrh, dst, (void *)src, len); + if (ret != len) + return -EFAULT; + + return 0; +} + +static inline int xfer_from_iotlb(const struct vringh *vrh, void *src, + void *dst, size_t len) +{ + int ret; + + ret = copy_from_iotlb(vrh, dst, src, len); + if (ret != len) + return -EFAULT; + + return 0; +} + +static inline int xfer_to_iotlb(const struct vringh *vrh, + void *dst, void *src, size_t len) +{ + int ret; + + ret = copy_to_iotlb(vrh, dst, src, len); + if (ret != len) + return -EFAULT; + + return 0; +} + +static inline int putused_iotlb(const struct vringh *vrh, + struct vring_used_elem *dst, + const struct vring_used_elem *src, + unsigned int num) +{ + int size = num * sizeof(*dst); + int ret; + + ret = copy_to_iotlb(vrh, dst, (void *)src, num * sizeof(*dst)); + if (ret != size) + return -EFAULT; + + return 0; +} + +/** + * vringh_init_iotlb - initialize a vringh for a ring with IOTLB. + * @vrh: the vringh to initialize. + * @features: the feature bits for this ring. + * @num: the number of elements. + * @weak_barriers: true if we only need memory barriers, not I/O. + * @desc: the userpace descriptor pointer. + * @avail: the userpace avail pointer. + * @used: the userpace used pointer. + * + * Returns an error if num is invalid. + */ +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) +{ + return vringh_init_kern(vrh, features, num, weak_barriers, + desc, avail, used); +} +EXPORT_SYMBOL(vringh_init_iotlb); + +/** + * vringh_set_iotlb - initialize a vringh for a ring with IOTLB. + * @vrh: the vring + * @iotlb: iotlb associated with this vring + */ +void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb) +{ + vrh->iotlb = iotlb; +} +EXPORT_SYMBOL(vringh_set_iotlb); + +/** + * vringh_getdesc_iotlb - get next available descriptor from ring with + * IOTLB. + * @vrh: the kernelspace vring. + * @riov: where to put the readable descriptors (or NULL) + * @wiov: where to put the writable descriptors (or NULL) + * @head: head index we received, for passing to vringh_complete_iotlb(). + * @gfp: flags for allocating larger riov/wiov. + * + * Returns 0 if there was no descriptor, 1 if there was, or -errno. + * + * Note that on error return, you can tell the difference between an + * invalid ring and a single invalid descriptor: in the former case, + * *head will be vrh->vring.num. You may be able to ignore an invalid + * descriptor, but there's not much you can do with an invalid ring. + * + * Note that you may need to clean up riov and wiov, even on error! + */ +int vringh_getdesc_iotlb(struct vringh *vrh, + struct vringh_kiov *riov, + struct vringh_kiov *wiov, + u16 *head, + gfp_t gfp) +{ + int err; + + err = __vringh_get_head(vrh, getu16_iotlb, &vrh->last_avail_idx); + if (err < 0) + return err; + + /* Empty... */ + if (err == vrh->vring.num) + return 0; + + *head = err; + err = __vringh_iov(vrh, *head, riov, wiov, no_range_check, NULL, + gfp, copydesc_iotlb); + if (err) + return err; + + return 1; +} +EXPORT_SYMBOL(vringh_getdesc_iotlb); + +/** + * vringh_iov_pull_iotlb - copy bytes from vring_iov. + * @vrh: the vring. + * @riov: the riov as passed to vringh_getdesc_iotlb() (updated as we consume) + * @dst: the place to copy. + * @len: the maximum length to copy. + * + * Returns the bytes copied <= len or a negative errno. + */ +ssize_t vringh_iov_pull_iotlb(struct vringh *vrh, + struct vringh_kiov *riov, + void *dst, size_t len) +{ + return vringh_iov_xfer(vrh, riov, dst, len, xfer_from_iotlb); +} +EXPORT_SYMBOL(vringh_iov_pull_iotlb); + +/** + * vringh_iov_push_iotlb - copy bytes into vring_iov. + * @vrh: the vring. + * @wiov: the wiov as passed to vringh_getdesc_iotlb() (updated as we consume) + * @dst: the place to copy. + * @len: the maximum length to copy. + * + * Returns the bytes copied <= len or a negative errno. + */ +ssize_t vringh_iov_push_iotlb(struct vringh *vrh, + struct vringh_kiov *wiov, + const void *src, size_t len) +{ + return vringh_iov_xfer(vrh, wiov, (void *)src, len, xfer_to_iotlb); +} +EXPORT_SYMBOL(vringh_iov_push_iotlb); + +/** + * vringh_abandon_iotlb - we've decided not to handle the descriptor(s). + * @vrh: the vring. + * @num: the number of descriptors to put back (ie. num + * vringh_get_iotlb() to undo). + * + * The next vringh_get_iotlb() will return the old descriptor(s) again. + */ +void vringh_abandon_iotlb(struct vringh *vrh, unsigned int num) +{ + /* We only update vring_avail_event(vr) when we want to be notified, + * so we haven't changed that yet. + */ + vrh->last_avail_idx -= num; +} +EXPORT_SYMBOL(vringh_abandon_iotlb); + +/** + * vringh_complete_iotlb - we've finished with descriptor, publish it. + * @vrh: the vring. + * @head: the head as filled in by vringh_getdesc_iotlb. + * @len: the length of data we have written. + * + * You should check vringh_need_notify_iotlb() after one or more calls + * to this function. + */ +int vringh_complete_iotlb(struct vringh *vrh, u16 head, u32 len) +{ + struct vring_used_elem used; + + used.id = cpu_to_vringh32(vrh, head); + used.len = cpu_to_vringh32(vrh, len); + + return __vringh_complete(vrh, &used, 1, putu16_iotlb, putused_iotlb); +} +EXPORT_SYMBOL(vringh_complete_iotlb); + +/** + * vringh_notify_enable_iotlb - we want to know if something changes. + * @vrh: the vring. + * + * This always enables notifications, but returns false if there are + * now more buffers available in the vring. + */ +bool vringh_notify_enable_iotlb(struct vringh *vrh) +{ + return __vringh_notify_enable(vrh, getu16_iotlb, putu16_iotlb); +} +EXPORT_SYMBOL(vringh_notify_enable_iotlb); + +/** + * vringh_notify_disable_iotlb - don't tell us if something changes. + * @vrh: the vring. + * + * This is our normal running state: we disable and then only enable when + * we're going to sleep. + */ +void vringh_notify_disable_iotlb(struct vringh *vrh) +{ + __vringh_notify_disable(vrh, putu16_iotlb); +} +EXPORT_SYMBOL(vringh_notify_disable_iotlb); + +/** + * vringh_need_notify_iotlb - must we tell the other side about used buffers? + * @vrh: the vring we've called vringh_complete_iotlb() on. + * + * Returns -errno or 0 if we don't need to tell the other side, 1 if we do. + */ +int vringh_need_notify_iotlb(struct vringh *vrh) +{ + return __vringh_need_notify(vrh, getu16_iotlb); +} +EXPORT_SYMBOL(vringh_need_notify_iotlb); + + MODULE_LICENSE("GPL"); |