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[85.223.209.52]) by smtp.gmail.com with ESMTPSA id y1-v6sm1102381lfg.10.2018.05.17.01.26.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 17 May 2018 01:26:16 -0700 (PDT) From: Oleksandr Andrushchenko To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, jgross@suse.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com Cc: daniel.vetter@intel.com, andr2000@gmail.com, dongwon.kim@intel.com, matthew.d.roper@intel.com, Oleksandr Andrushchenko Subject: [Xen-devel][RFC 3/3] xen/gntdev: Add support for Linux dma buffers Date: Thu, 17 May 2018 11:26:04 +0300 Message-Id: <20180517082604.14828-4-andr2000@gmail.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180517082604.14828-1-andr2000@gmail.com> References: <20180517082604.14828-1-andr2000@gmail.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Oleksandr Andrushchenko Signed-off-by: Oleksandr Andrushchenko --- drivers/xen/gntdev.c | 954 +++++++++++++++++++++++++++++++++++++- include/uapi/xen/gntdev.h | 101 ++++ include/xen/gntdev_exp.h | 23 + 3 files changed, 1066 insertions(+), 12 deletions(-) create mode 100644 include/xen/gntdev_exp.h diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 9510f228efe9..0ee88e193362 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -4,6 +4,8 @@ * Device for accessing (in user-space) pages that have been granted by other * domains. * + * DMA buffer implementation is based on drivers/gpu/drm/drm_prime.c. + * * Copyright (c) 2006-2007, D G Murray. * (c) 2009 Gerd Hoffmann * @@ -37,6 +39,9 @@ #include #include +#include +#include + #include #include #include @@ -61,16 +66,39 @@ static atomic_t pages_mapped = ATOMIC_INIT(0); static int use_ptemod; #define populate_freeable_maps use_ptemod +#ifndef GRANT_INVALID_REF +/* + * Note on usage of grant reference 0 as invalid grant reference: + * grant reference 0 is valid, but never exposed to a driver, + * because of the fact it is already in use/reserved by the PV console. + */ +#define GRANT_INVALID_REF 0 +#endif + struct gntdev_priv { /* maps with visible offsets in the file descriptor */ struct list_head maps; /* maps that are not visible; will be freed on munmap. * Only populated if populate_freeable_maps == 1 */ struct list_head freeable_maps; + /* List of dma-bufs. */ + struct list_head dma_bufs; /* lock protects maps and freeable_maps */ struct mutex lock; struct mm_struct *mm; struct mmu_notifier mn; + + /* Private data of the hyper DMA buffers. */ + + struct device *dev; + /* List of exported DMA buffers. */ + struct list_head dmabuf_exp_list; + /* List of wait objects. */ + struct list_head dmabuf_exp_wait_list; + /* List of imported DMA buffers. */ + struct list_head dmabuf_imp_list; + /* This is the lock which protects dma_buf_xxx lists. */ + struct mutex dmabuf_lock; }; struct unmap_notify { @@ -95,10 +123,65 @@ struct grant_map { struct gnttab_unmap_grant_ref *kunmap_ops; struct page **pages; unsigned long pages_vm_start; + + /* + * All the fields starting with dmabuf_ are only valid if this + * mapping is used for exporting a DMA buffer. + * If dmabuf_vaddr is not NULL then this mapping is backed by DMA + * capable memory. + */ + + /* Flags used to create this DMA buffer: GNTDEV_DMABUF_FLAG_XXX. */ + bool dmabuf_flags; + /* Virtual/CPU address of the DMA buffer. */ + void *dmabuf_vaddr; + /* Bus address of the DMA buffer. */ + dma_addr_t dmabuf_bus_addr; +}; + +struct hyper_dmabuf { + struct gntdev_priv *priv; + struct dma_buf *dmabuf; + struct list_head next; + int fd; + + union { + struct { + /* Exported buffers are reference counted. */ + struct kref refcount; + struct grant_map *map; + } exp; + struct { + /* Granted references of the imported buffer. */ + grant_ref_t *refs; + /* Scatter-gather table of the imported buffer. */ + struct sg_table *sgt; + /* dma-buf attachment of the imported buffer. */ + struct dma_buf_attachment *attach; + } imp; + } u; + + /* Number of pages this buffer has. */ + int nr_pages; + /* Pages of this buffer. */ + struct page **pages; +}; + +struct hyper_dmabuf_wait_obj { + struct list_head next; + struct hyper_dmabuf *hyper_dmabuf; + struct completion completion; +}; + +struct hyper_dambuf_attachment { + struct sg_table *sgt; + enum dma_data_direction dir; }; static int unmap_grant_pages(struct grant_map *map, int offset, int pages); +static struct miscdevice gntdev_miscdev; + /* ------------------------------------------------------------------ */ static void gntdev_print_maps(struct gntdev_priv *priv, @@ -120,8 +203,17 @@ static void gntdev_free_map(struct grant_map *map) if (map == NULL) return; - if (map->pages) + if (map->dmabuf_vaddr) { + bool coherent = map->dmabuf_flags & + GNTDEV_DMABUF_FLAG_DMA_COHERENT; + + gnttab_dma_free_pages(gntdev_miscdev.this_device, + coherent, map->count, map->pages, + map->dmabuf_vaddr, map->dmabuf_bus_addr); + } else if (map->pages) { gnttab_free_pages(map->count, map->pages); + } + kfree(map->pages); kfree(map->grants); kfree(map->map_ops); @@ -131,7 +223,7 @@ static void gntdev_free_map(struct grant_map *map) kfree(map); } -static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count) +static struct grant_map *gntdev_alloc_map(int count, int dmabuf_flags) { struct grant_map *add; int i; @@ -154,8 +246,26 @@ static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count) NULL == add->pages) goto err; - if (gnttab_alloc_pages(count, add->pages)) - goto err; + add->dmabuf_flags = dmabuf_flags; + + /* + * Check if this mapping is requested to be backed + * by a DMA buffer. + */ + if (dmabuf_flags & (GNTDEV_DMABUF_FLAG_DMA_WC | + GNTDEV_DMABUF_FLAG_DMA_COHERENT)) { + bool coherent = dmabuf_flags & GNTDEV_DMABUF_FLAG_DMA_COHERENT; + + if (gnttab_dma_alloc_pages(gntdev_miscdev.this_device, + coherent, + count, add->pages, + &add->dmabuf_vaddr, + &add->dmabuf_bus_addr)) + goto err; + } else { + if (gnttab_alloc_pages(count, add->pages)) + goto err; + } for (i = 0; i < count; i++) { add->map_ops[i].handle = -1; @@ -233,6 +343,15 @@ static void gntdev_put_map(struct gntdev_priv *priv, struct grant_map *map) gntdev_free_map(map); } +static void gntdev_put_map_unlink(struct gntdev_priv *priv, + struct grant_map *map) +{ + mutex_lock(&priv->lock); + list_del(&map->next); + gntdev_put_map(NULL /* already removed */, map); + mutex_unlock(&priv->lock); +} + /* ------------------------------------------------------------------ */ static int find_grant_ptes(pte_t *pte, pgtable_t token, @@ -324,6 +443,12 @@ static int map_grant_pages(struct grant_map *map) map->unmap_ops[i].handle = map->map_ops[i].handle; if (use_ptemod) map->kunmap_ops[i].handle = map->kmap_ops[i].handle; + else if (map->dmabuf_vaddr) { + unsigned long mfn; + + mfn = __pfn_to_mfn(page_to_pfn(map->pages[i])); + map->unmap_ops[i].dev_bus_addr = __pfn_to_phys(mfn); + } } return err; } @@ -527,19 +652,48 @@ static const struct mmu_notifier_ops gntdev_mmu_ops = { /* ------------------------------------------------------------------ */ -static int gntdev_open(struct inode *inode, struct file *flip) +struct gntdev_priv *gntdev_alloc_context(struct device *dev) { struct gntdev_priv *priv; - int ret = 0; priv = kzalloc(sizeof(*priv), GFP_KERNEL); if (!priv) - return -ENOMEM; + return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&priv->maps); INIT_LIST_HEAD(&priv->freeable_maps); mutex_init(&priv->lock); + priv->dev = dev; + mutex_init(&priv->dmabuf_lock); + INIT_LIST_HEAD(&priv->dmabuf_exp_list); + INIT_LIST_HEAD(&priv->dmabuf_exp_wait_list); + INIT_LIST_HEAD(&priv->dmabuf_imp_list); + + /* + * The device is not spawn from a device tree, so arch_setup_dma_ops + * is not called, thus leaving the device with dummy DMA ops. + * This makes the device return error on PRIME buffer import, which + * is not correct: to fix this call of_dma_configure() with a NULL + * node to set default DMA ops. + */ + of_dma_configure(dev, NULL); + + pr_debug("priv %p\n", priv); + + return priv; +} +EXPORT_SYMBOL(gntdev_alloc_context); + +static int gntdev_open(struct inode *inode, struct file *flip) +{ + struct gntdev_priv *priv; + int ret = 0; + + priv = gntdev_alloc_context(gntdev_miscdev.this_device); + if (IS_ERR(priv)) + return PTR_ERR(priv); + if (use_ptemod) { priv->mm = get_task_mm(current); if (!priv->mm) { @@ -557,14 +711,12 @@ static int gntdev_open(struct inode *inode, struct file *flip) } flip->private_data = priv; - pr_debug("priv %p\n", priv); return 0; } -static int gntdev_release(struct inode *inode, struct file *flip) +void gntdev_free_context(struct gntdev_priv *priv) { - struct gntdev_priv *priv = flip->private_data; struct grant_map *map; pr_debug("priv %p\n", priv); @@ -576,11 +728,28 @@ static int gntdev_release(struct inode *inode, struct file *flip) gntdev_put_map(NULL /* already removed */, map); } WARN_ON(!list_empty(&priv->freeable_maps)); + mutex_unlock(&priv->lock); + WARN(!list_empty(&priv->dmabuf_exp_list), + "Removing with non-empty exported DMA buffer list!\n"); + WARN(!list_empty(&priv->dmabuf_exp_wait_list), + "Removing with pending wait objects!\n"); + WARN(!list_empty(&priv->dmabuf_imp_list), + "Removing with non-empty imported DMA buffer list!\n"); + + kfree(priv); +} +EXPORT_SYMBOL(gntdev_free_context); + +static int gntdev_release(struct inode *inode, struct file *flip) +{ + struct gntdev_priv *priv = flip->private_data; + if (use_ptemod) mmu_notifier_unregister(&priv->mn, priv->mm); - kfree(priv); + + gntdev_free_context(priv); return 0; } @@ -598,7 +767,7 @@ static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, return -EINVAL; err = -ENOMEM; - map = gntdev_alloc_map(priv, op.count); + map = gntdev_alloc_map(op.count, 0 /* this is not a dma-buf */); if (!map) return err; @@ -949,6 +1118,755 @@ static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u) return ret; } +/* ------------------------------------------------------------------ */ +/* DMA buffer support. */ +/* ------------------------------------------------------------------ */ + +/* ------------------------------------------------------------------ */ +/* Implementation of wait for exported DMA buffer released. */ +/* ------------------------------------------------------------------ */ + +static void dmabuf_exp_release(struct kref *kref); + +static struct hyper_dmabuf_wait_obj * +dmabuf_exp_wait_obj_new(struct gntdev_priv *priv, + struct hyper_dmabuf *hyper_dmabuf) +{ + struct hyper_dmabuf_wait_obj *obj; + + obj = kzalloc(sizeof(*obj), GFP_KERNEL); + if (!obj) + return ERR_PTR(-ENOMEM); + + init_completion(&obj->completion); + obj->hyper_dmabuf = hyper_dmabuf; + + mutex_lock(&priv->dmabuf_lock); + list_add(&obj->next, &priv->dmabuf_exp_wait_list); + /* Put our reference and wait for hyper_dmabuf's release to fire. */ + kref_put(&hyper_dmabuf->u.exp.refcount, dmabuf_exp_release); + mutex_unlock(&priv->dmabuf_lock); + return obj; +} + +static void dmabuf_exp_wait_obj_free(struct gntdev_priv *priv, + struct hyper_dmabuf_wait_obj *obj) +{ + struct hyper_dmabuf_wait_obj *cur_obj, *q; + + mutex_lock(&priv->dmabuf_lock); + list_for_each_entry_safe(cur_obj, q, &priv->dmabuf_exp_wait_list, next) + if (cur_obj == obj) { + list_del(&obj->next); + kfree(obj); + break; + } + mutex_unlock(&priv->dmabuf_lock); +} + +static int dmabuf_exp_wait_obj_wait(struct hyper_dmabuf_wait_obj *obj, + u32 wait_to_ms) +{ + if (wait_for_completion_timeout(&obj->completion, + msecs_to_jiffies(wait_to_ms)) <= 0) + return -ETIMEDOUT; + + return 0; +} + +static void dmabuf_exp_wait_obj_signal(struct gntdev_priv *priv, + struct hyper_dmabuf *hyper_dmabuf) +{ + struct hyper_dmabuf_wait_obj *obj, *q; + + list_for_each_entry_safe(obj, q, &priv->dmabuf_exp_wait_list, next) + if (obj->hyper_dmabuf == hyper_dmabuf) { + pr_debug("Found hyper_dmabuf in the wait list, wake\n"); + complete_all(&obj->completion); + } +} + +static struct hyper_dmabuf * +dmabuf_exp_wait_obj_get_by_fd(struct gntdev_priv *priv, int fd) +{ + struct hyper_dmabuf *q, *hyper_dmabuf, *ret = ERR_PTR(-ENOENT); + + mutex_lock(&priv->dmabuf_lock); + list_for_each_entry_safe(hyper_dmabuf, q, &priv->dmabuf_exp_list, next) + if (hyper_dmabuf->fd == fd) { + pr_debug("Found hyper_dmabuf in the wait list\n"); + kref_get(&hyper_dmabuf->u.exp.refcount); + ret = hyper_dmabuf; + break; + } + mutex_unlock(&priv->dmabuf_lock); + return ret; +} + +static int dmabuf_exp_wait_released(struct gntdev_priv *priv, int fd, + int wait_to_ms) +{ + struct hyper_dmabuf *hyper_dmabuf; + struct hyper_dmabuf_wait_obj *obj; + int ret; + + pr_debug("Will wait for dma-buf with fd %d\n", fd); + /* + * Try to find the DMA buffer: if not found means that + * either the buffer has already been released or file descriptor + * provided is wrong. + */ + hyper_dmabuf = dmabuf_exp_wait_obj_get_by_fd(priv, fd); + if (IS_ERR(hyper_dmabuf)) + return PTR_ERR(hyper_dmabuf); + + /* + * hyper_dmabuf still exists and is reference count locked by us now, + * so prepare to wait: allocate wait object and add it to the wait list, + * so we can find it on release. + */ + obj = dmabuf_exp_wait_obj_new(priv, hyper_dmabuf); + if (IS_ERR(obj)) { + pr_err("Failed to setup wait object, ret %ld\n", PTR_ERR(obj)); + return PTR_ERR(obj); + } + + ret = dmabuf_exp_wait_obj_wait(obj, wait_to_ms); + dmabuf_exp_wait_obj_free(priv, obj); + return ret; +} + +/* ------------------------------------------------------------------ */ +/* DMA buffer export support. */ +/* ------------------------------------------------------------------ */ + +static struct sg_table * +dmabuf_pages_to_sgt(struct page **pages, unsigned int nr_pages) +{ + struct sg_table *sgt; + int ret; + + sgt = kmalloc(sizeof(struct sg_table), GFP_KERNEL); + if (!sgt) { + ret = -ENOMEM; + goto out; + } + + ret = sg_alloc_table_from_pages(sgt, pages, nr_pages, 0, + nr_pages << PAGE_SHIFT, + GFP_KERNEL); + if (ret) + goto out; + + return sgt; + +out: + kfree(sgt); + return ERR_PTR(ret); +} + +static int dmabuf_exp_ops_attach(struct dma_buf *dma_buf, + struct device *target_dev, + struct dma_buf_attachment *attach) +{ + struct hyper_dambuf_attachment *hyper_dambuf_attach; + + hyper_dambuf_attach = kzalloc(sizeof(*hyper_dambuf_attach), GFP_KERNEL); + if (!hyper_dambuf_attach) + return -ENOMEM; + + hyper_dambuf_attach->dir = DMA_NONE; + attach->priv = hyper_dambuf_attach; + /* Might need to pin the pages of the buffer now. */ + return 0; +} + +static void dmabuf_exp_ops_detach(struct dma_buf *dma_buf, + struct dma_buf_attachment *attach) +{ + struct hyper_dambuf_attachment *hyper_dambuf_attach = attach->priv; + + if (hyper_dambuf_attach) { + struct sg_table *sgt = hyper_dambuf_attach->sgt; + + if (sgt) { + if (hyper_dambuf_attach->dir != DMA_NONE) + dma_unmap_sg_attrs(attach->dev, sgt->sgl, + sgt->nents, + hyper_dambuf_attach->dir, + DMA_ATTR_SKIP_CPU_SYNC); + sg_free_table(sgt); + } + + kfree(sgt); + kfree(hyper_dambuf_attach); + attach->priv = NULL; + } + /* Might need to unpin the pages of the buffer now. */ +} + +static struct sg_table * +dmabuf_exp_ops_map_dma_buf(struct dma_buf_attachment *attach, + enum dma_data_direction dir) +{ + struct hyper_dambuf_attachment *hyper_dambuf_attach = attach->priv; + struct hyper_dmabuf *hyper_dmabuf = attach->dmabuf->priv; + struct sg_table *sgt; + + pr_debug("Mapping %d pages for dev %p\n", hyper_dmabuf->nr_pages, + attach->dev); + + if (WARN_ON(dir == DMA_NONE || !hyper_dambuf_attach)) + return ERR_PTR(-EINVAL); + + /* Return the cached mapping when possible. */ + if (hyper_dambuf_attach->dir == dir) + return hyper_dambuf_attach->sgt; + + /* + * Two mappings with different directions for the same attachment are + * not allowed. + */ + if (WARN_ON(hyper_dambuf_attach->dir != DMA_NONE)) + return ERR_PTR(-EBUSY); + + sgt = dmabuf_pages_to_sgt(hyper_dmabuf->pages, hyper_dmabuf->nr_pages); + if (!IS_ERR(sgt)) { + if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir, + DMA_ATTR_SKIP_CPU_SYNC)) { + sg_free_table(sgt); + kfree(sgt); + sgt = ERR_PTR(-ENOMEM); + } else { + hyper_dambuf_attach->sgt = sgt; + hyper_dambuf_attach->dir = dir; + } + } + if (IS_ERR(sgt) + pr_err("Failed to map sg table for dev %p\n", attach->dev); + return sgt; +} + +static void dmabuf_exp_ops_unmap_dma_buf(struct dma_buf_attachment *attach, + struct sg_table *sgt, + enum dma_data_direction dir) +{ + /* Not implemented. The unmap is done at dmabuf_exp_ops_detach(). */ +} + +static void dmabuf_exp_release(struct kref *kref) +{ + struct hyper_dmabuf *hyper_dmabuf = + container_of(kref, struct hyper_dmabuf, + u.exp.refcount); + + dmabuf_exp_wait_obj_signal(hyper_dmabuf->priv, hyper_dmabuf); + list_del(&hyper_dmabuf->next); + kfree(hyper_dmabuf); +} + +static void dmabuf_exp_ops_release(struct dma_buf *dma_buf) +{ + struct hyper_dmabuf *hyper_dmabuf = dma_buf->priv; + struct gntdev_priv *priv = hyper_dmabuf->priv; + + gntdev_put_map_unlink(priv, hyper_dmabuf->u.exp.map); + mutex_lock(&priv->dmabuf_lock); + kref_put(&hyper_dmabuf->u.exp.refcount, dmabuf_exp_release); + mutex_unlock(&priv->dmabuf_lock); +} + +static void *dmabuf_exp_ops_kmap_atomic(struct dma_buf *dma_buf, + unsigned long page_num) +{ + /* Not implemented. */ + return NULL; +} + +static void *dmabuf_exp_ops_kmap(struct dma_buf *dma_buf, + unsigned long page_num) +{ + /* Not implemented. */ + return NULL; +} + +static int dmabuf_exp_ops_mmap(struct dma_buf *dma_buf, + struct vm_area_struct *vma) +{ + /* Not implemented. */ + return 0; +} + +static const struct dma_buf_ops dmabuf_exp_ops = { + .attach = dmabuf_exp_ops_attach, + .detach = dmabuf_exp_ops_detach, + .map_dma_buf = dmabuf_exp_ops_map_dma_buf, + .unmap_dma_buf = dmabuf_exp_ops_unmap_dma_buf, + .release = dmabuf_exp_ops_release, + .kmap = dmabuf_exp_ops_kmap, + .kmap_atomic = dmabuf_exp_ops_kmap_atomic, + .mmap = dmabuf_exp_ops_mmap, +}; + +static int dmabuf_export(struct gntdev_priv *priv, struct grant_map *map, + int *fd) +{ + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct hyper_dmabuf *hyper_dmabuf; + int ret = 0; + + hyper_dmabuf = kzalloc(sizeof(*hyper_dmabuf), GFP_KERNEL); + if (!hyper_dmabuf) + return -ENOMEM; + + kref_init(&hyper_dmabuf->u.exp.refcount); + + hyper_dmabuf->priv = priv; + hyper_dmabuf->nr_pages = map->count; + hyper_dmabuf->pages = map->pages; + hyper_dmabuf->u.exp.map = map; + + exp_info.exp_name = KBUILD_MODNAME; + exp_info.ops = &dmabuf_exp_ops; + exp_info.size = map->count << PAGE_SHIFT; + exp_info.flags = O_RDWR; + exp_info.priv = hyper_dmabuf; + + hyper_dmabuf->dmabuf = dma_buf_export(&exp_info); + if (IS_ERR(hyper_dmabuf->dmabuf)) { + ret = PTR_ERR(hyper_dmabuf->dmabuf); + hyper_dmabuf->dmabuf = NULL; + goto fail; + } + + ret = dma_buf_fd(hyper_dmabuf->dmabuf, O_CLOEXEC); + if (ret < 0) + goto fail; + + hyper_dmabuf->fd = ret; + *fd = ret; + + pr_debug("Exporting DMA buffer with fd %d\n", ret); + + mutex_lock(&priv->dmabuf_lock); + list_add(&hyper_dmabuf->next, &priv->dmabuf_exp_list); + mutex_unlock(&priv->dmabuf_lock); + return 0; + +fail: + if (hyper_dmabuf->dmabuf) + dma_buf_put(hyper_dmabuf->dmabuf); + kfree(hyper_dmabuf); + return ret; +} + +static struct grant_map * +dmabuf_exp_alloc_backing_storage(int dmabuf_flags, int count) +{ + struct grant_map *map; + + if (unlikely(count <= 0)) + return ERR_PTR(-EINVAL); + + if ((dmabuf_flags & GNTDEV_DMABUF_FLAG_DMA_WC) && + (dmabuf_flags & GNTDEV_DMABUF_FLAG_DMA_COHERENT)) { + pr_err("Wrong dma-buf flags: either WC or coherent, not both\n"); + return ERR_PTR(-EINVAL); + } + + map = gntdev_alloc_map(count, dmabuf_flags); + if (!map) + return ERR_PTR(-ENOMEM); + + if (unlikely(atomic_add_return(count, &pages_mapped) > limit)) { + pr_err("can't map: over limit\n"); + gntdev_put_map(NULL, map); + return ERR_PTR(-ENOMEM); + } + return map; +} + +int gntdev_dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags, + int count, u32 domid, u32 *refs, u32 *fd) +{ + struct grant_map *map; + int i, ret; + + *fd = -1; + + if (use_ptemod) { + pr_err("Cannot provide dma-buf: use_ptemode %d\n", + use_ptemod); + return -EINVAL; + } + + map = dmabuf_exp_alloc_backing_storage(flags, count); + if (IS_ERR(map)) + return PTR_ERR(map); + + for (i = 0; i < count; i++) { + map->grants[i].domid = domid; + map->grants[i].ref = refs[i]; + } + + mutex_lock(&priv->lock); + gntdev_add_map(priv, map); + mutex_unlock(&priv->lock); + + map->flags |= GNTMAP_host_map; +#if defined(CONFIG_X86) + map->flags |= GNTMAP_device_map; +#endif + + ret = map_grant_pages(map); + if (ret < 0) + goto out; + + ret = dmabuf_export(priv, map, fd); + if (ret < 0) + goto out; + + return 0; + +out: + gntdev_put_map_unlink(priv, map); + return ret; +} +EXPORT_SYMBOL(gntdev_dmabuf_exp_from_refs); + +static long +gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv, + struct ioctl_gntdev_dmabuf_exp_from_refs __user *u) +{ + struct ioctl_gntdev_dmabuf_exp_from_refs op; + u32 *refs; + long ret; + + if (copy_from_user(&op, u, sizeof(op)) != 0) + return -EFAULT; + + refs = kcalloc(op.count, sizeof(*refs), GFP_KERNEL); + if (!refs) + return -ENOMEM; + + if (copy_from_user(refs, u->refs, sizeof(*refs) * op.count) != 0) { + ret = -EFAULT; + goto out; + } + + ret = gntdev_dmabuf_exp_from_refs(priv, op.flags, op.count, + op.domid, refs, &op.fd); + if (ret) + goto out; + + if (copy_to_user(u, &op, sizeof(op)) != 0) + ret = -EFAULT; + +out: + kfree(refs); + return ret; +} + +static long +gntdev_ioctl_dmabuf_exp_wait_released(struct gntdev_priv *priv, + struct ioctl_gntdev_dmabuf_exp_wait_released __user *u) +{ + struct ioctl_gntdev_dmabuf_exp_wait_released op; + + if (copy_from_user(&op, u, sizeof(op)) != 0) + return -EFAULT; + + return dmabuf_exp_wait_released(priv, op.fd, op.wait_to_ms); +} + +int gntdev_dmabuf_exp_wait_released(struct gntdev_priv *priv, u32 fd, + int wait_to_ms) +{ + return dmabuf_exp_wait_released(priv, fd, wait_to_ms); +} +EXPORT_SYMBOL(gntdev_dmabuf_exp_wait_released); + +/* ------------------------------------------------------------------ */ +/* DMA buffer import support. */ +/* ------------------------------------------------------------------ */ + +static int +dmabuf_imp_grant_foreign_access(struct page **pages, u32 *refs, + int count, int domid) +{ + grant_ref_t priv_gref_head; + int i, ret; + + ret = gnttab_alloc_grant_references(count, &priv_gref_head); + if (ret < 0) { + pr_err("Cannot allocate grant references, ret %d\n", ret); + return ret; + } + + for (i = 0; i < count; i++) { + int cur_ref; + + cur_ref = gnttab_claim_grant_reference(&priv_gref_head); + if (cur_ref < 0) { + ret = cur_ref; + pr_err("Cannot claim grant reference, ret %d\n", ret); + goto out; + } + + gnttab_grant_foreign_access_ref(cur_ref, domid, + xen_page_to_gfn(pages[i]), 0); + refs[i] = cur_ref; + } + + ret = 0; + +out: + gnttab_free_grant_references(priv_gref_head); + return ret; +} + +static void dmabuf_imp_end_foreign_access(u32 *refs, int count) +{ + int i; + + for (i = 0; i < count; i++) + if (refs[i] != GRANT_INVALID_REF) + gnttab_end_foreign_access(refs[i], 0, 0UL); +} + +static void dmabuf_imp_free_storage(struct hyper_dmabuf *hyper_dmabuf) +{ + kfree(hyper_dmabuf->pages); + kfree(hyper_dmabuf->u.imp.refs); + kfree(hyper_dmabuf); +} + +static struct hyper_dmabuf *dmabuf_imp_alloc_storage(int count) +{ + struct hyper_dmabuf *hyper_dmabuf; + int i; + + hyper_dmabuf = kzalloc(sizeof(*hyper_dmabuf), GFP_KERNEL); + if (!hyper_dmabuf) + goto fail; + + hyper_dmabuf->u.imp.refs = kcalloc(count, + sizeof(hyper_dmabuf->u.imp.refs[0]), + GFP_KERNEL); + if (!hyper_dmabuf->u.imp.refs) + goto fail; + + hyper_dmabuf->pages = kcalloc(count, + sizeof(hyper_dmabuf->pages[0]), + GFP_KERNEL); + if (!hyper_dmabuf->pages) + goto fail; + + hyper_dmabuf->nr_pages = count; + + for (i = 0; i < count; i++) + hyper_dmabuf->u.imp.refs[i] = GRANT_INVALID_REF; + + return hyper_dmabuf; + +fail: + dmabuf_imp_free_storage(hyper_dmabuf); + return ERR_PTR(-ENOMEM); +} + +static struct hyper_dmabuf * +dmabuf_import(struct gntdev_priv *priv, int fd, int count, int domid) +{ + struct hyper_dmabuf *hyper_dmabuf, *ret; + struct dma_buf *dma_buf; + struct dma_buf_attachment *attach; + struct sg_table *sgt; + struct sg_page_iter sg_iter; + int i; + + dma_buf = dma_buf_get(fd); + if (IS_ERR(dma_buf)) + return ERR_CAST(dma_buf); + + hyper_dmabuf = dmabuf_imp_alloc_storage(count); + if (IS_ERR(hyper_dmabuf)) { + ret = hyper_dmabuf; + goto fail_put; + } + + hyper_dmabuf->priv = priv; + hyper_dmabuf->fd = fd; + + attach = dma_buf_attach(dma_buf, priv->dev); + if (IS_ERR(attach)) { + ret = ERR_CAST(attach); + goto fail_free_obj; + } + + hyper_dmabuf->u.imp.attach = attach; + + sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL); + if (IS_ERR(sgt)) { + ret = ERR_CAST(sgt); + goto fail_detach; + } + + /* Check number of pages that imported buffer has. */ + if (attach->dmabuf->size != hyper_dmabuf->nr_pages << PAGE_SHIFT) { + ret = ERR_PTR(-EINVAL); + pr_err("DMA buffer has %zu pages, user-space expects %d\n", + attach->dmabuf->size, hyper_dmabuf->nr_pages); + goto fail_unmap; + } + + hyper_dmabuf->u.imp.sgt = sgt; + + /* Now convert sgt to array of pages and check for page validity. */ + i = 0; + for_each_sg_page(sgt->sgl, &sg_iter, sgt->nents, 0) { + struct page *page = sg_page_iter_page(&sg_iter); + /* + * Check if page is valid: this can happen if we are given + * a page from VRAM or other resources which are not backed + * by a struct page. + */ + if (!pfn_valid(page_to_pfn(page))) { + ret = ERR_PTR(-EINVAL); + goto fail_unmap; + } + + hyper_dmabuf->pages[i++] = page; + } + + ret = ERR_PTR(dmabuf_imp_grant_foreign_access(hyper_dmabuf->pages, + hyper_dmabuf->u.imp.refs, + count, domid)); + if (IS_ERR(ret)) + goto fail_end_access; + + pr_debug("Imported DMA buffer with fd %d\n", fd); + + mutex_lock(&priv->dmabuf_lock); + list_add(&hyper_dmabuf->next, &priv->dmabuf_imp_list); + mutex_unlock(&priv->dmabuf_lock); + + return hyper_dmabuf; + +fail_end_access: + dmabuf_imp_end_foreign_access(hyper_dmabuf->u.imp.refs, count); +fail_unmap: + dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL); +fail_detach: + dma_buf_detach(dma_buf, attach); +fail_free_obj: + dmabuf_imp_free_storage(hyper_dmabuf); +fail_put: + dma_buf_put(dma_buf); + return ret; +} + +/* + * Find the hyper dma-buf by its file descriptor and remove + * it from the buffer's list. + */ +static struct hyper_dmabuf * +dmabuf_imp_find_unlink(struct gntdev_priv *priv, int fd) +{ + struct hyper_dmabuf *q, *hyper_dmabuf, *ret = ERR_PTR(-ENOENT); + + mutex_lock(&priv->dmabuf_lock); + list_for_each_entry_safe(hyper_dmabuf, q, &priv->dmabuf_imp_list, next) { + if (hyper_dmabuf->fd == fd) { + pr_debug("Found hyper_dmabuf in the import list\n"); + ret = hyper_dmabuf; + list_del(&hyper_dmabuf->next); + break; + } + } + mutex_unlock(&priv->dmabuf_lock); + return ret; +} + +int gntdev_dmabuf_imp_release(struct gntdev_priv *priv, u32 fd) +{ + struct hyper_dmabuf *hyper_dmabuf; + struct dma_buf_attachment *attach; + struct dma_buf *dma_buf; + + hyper_dmabuf = dmabuf_imp_find_unlink(priv, fd); + if (IS_ERR(hyper_dmabuf)) + return PTR_ERR(hyper_dmabuf); + + pr_debug("Releasing DMA buffer with fd %d\n", fd); + + attach = hyper_dmabuf->u.imp.attach; + + if (hyper_dmabuf->u.imp.sgt) + dma_buf_unmap_attachment(attach, hyper_dmabuf->u.imp.sgt, + DMA_BIDIRECTIONAL); + dma_buf = attach->dmabuf; + dma_buf_detach(attach->dmabuf, attach); + dma_buf_put(dma_buf); + + dmabuf_imp_end_foreign_access(hyper_dmabuf->u.imp.refs, + hyper_dmabuf->nr_pages); + dmabuf_imp_free_storage(hyper_dmabuf); + return 0; +} +EXPORT_SYMBOL(gntdev_dmabuf_imp_release); + +static long +gntdev_ioctl_dmabuf_imp_release(struct gntdev_priv *priv, + struct ioctl_gntdev_dmabuf_imp_release __user *u) +{ + struct ioctl_gntdev_dmabuf_imp_release op; + + if (copy_from_user(&op, u, sizeof(op)) != 0) + return -EFAULT; + + return gntdev_dmabuf_imp_release(priv, op.fd); +} + +static long +gntdev_ioctl_dmabuf_imp_to_refs(struct gntdev_priv *priv, + struct ioctl_gntdev_dmabuf_imp_to_refs __user *u) +{ + struct ioctl_gntdev_dmabuf_imp_to_refs op; + struct hyper_dmabuf *hyper_dmabuf; + long ret; + + if (copy_from_user(&op, u, sizeof(op)) != 0) + return -EFAULT; + + hyper_dmabuf = dmabuf_import(priv, op.fd, op.count, op.domid); + if (IS_ERR(hyper_dmabuf)) + return PTR_ERR(hyper_dmabuf); + + if (copy_to_user(u->refs, hyper_dmabuf->u.imp.refs, + sizeof(*u->refs) * op.count) != 0) { + ret = -EFAULT; + goto out_release; + } + return 0; + +out_release: + gntdev_dmabuf_imp_release(priv, op.fd); + return ret; +} + +u32 *gntdev_dmabuf_imp_to_refs(struct gntdev_priv *priv, int fd, + int count, int domid, u32 **refs) +{ + struct hyper_dmabuf *hyper_dmabuf; + + hyper_dmabuf = dmabuf_import(priv, fd, count, domid); + if (IS_ERR(hyper_dmabuf)) + return ERR_CAST(hyper_dmabuf); + + return hyper_dmabuf->u.imp.refs; +} +EXPORT_SYMBOL(gntdev_dmabuf_imp_to_refs); + static long gntdev_ioctl(struct file *flip, unsigned int cmd, unsigned long arg) { @@ -971,6 +1889,18 @@ static long gntdev_ioctl(struct file *flip, case IOCTL_GNTDEV_GRANT_COPY: return gntdev_ioctl_grant_copy(priv, ptr); + case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS: + return gntdev_ioctl_dmabuf_exp_from_refs(priv, ptr); + + case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED: + return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr); + + case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS: + return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr); + + case IOCTL_GNTDEV_DMABUF_IMP_RELEASE: + return gntdev_ioctl_dmabuf_imp_release(priv, ptr); + default: pr_debug("priv %p, unknown cmd %x\n", priv, cmd); return -ENOIOCTLCMD; diff --git a/include/uapi/xen/gntdev.h b/include/uapi/xen/gntdev.h index d0661977667e..7cf7ca31db21 100644 --- a/include/uapi/xen/gntdev.h +++ b/include/uapi/xen/gntdev.h @@ -199,4 +199,105 @@ struct ioctl_gntdev_grant_copy { /* Send an interrupt on the indicated event channel */ #define UNMAP_NOTIFY_SEND_EVENT 0x2 +/* + * Create a dma-buf [1] from grant references @refs of count @count provided + * by the foreign domain @domid with flags @flags. + * + * By default dma-buf is backed by system memory pages, but by providing + * GNTDEV_DMABUF_FLAG_DMA flag it can also be created as a DMA write-combine + * buffer, e.g. allocated with dma_alloc_wc. + * + * Returns 0 if dma-buf was successfully created and the corresponding + * dma-buf's file descriptor is returned in @fd. + * + * [1] https://elixir.bootlin.com/linux/latest/source/Documentation/driver-api/dma-buf.rst + */ + +/* + * Request dma-buf backing storage to be allocated with DMA API: + * the buffer is backed with memory allocated with dma_alloc_wc. + */ +#define GNTDEV_DMABUF_FLAG_DMA_WC (1 << 1) + +/* + * Request dma-buf backing storage to be allocated with DMA API: + * the buffer is backed with memory allocated with dma_alloc_coherent. + */ +#define GNTDEV_DMABUF_FLAG_DMA_COHERENT (1 << 2) + +#define IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS \ + _IOC(_IOC_NONE, 'G', 9, \ + sizeof(struct ioctl_gntdev_dmabuf_exp_from_refs)) +struct ioctl_gntdev_dmabuf_exp_from_refs { + /* IN parameters. */ + /* Specific options for this dma-buf: see GNTDEV_DMABUF_FLAG_XXX. */ + __u32 flags; + /* Number of grant references in @refs array. */ + __u32 count; + /* OUT parameters. */ + /* File descriptor of the dma-buf. */ + __u32 fd; + /* The domain ID of the grant references to be mapped. */ + __u32 domid; + /* Variable IN parameter. */ + /* Array of grant references of size @count. */ + __u32 refs[1]; +}; + +/* + * This will block until the dma-buf with the file descriptor @fd is + * released. This is only valid for buffers created with + * IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS. + * + * If withing @wait_to_ms milliseconds the buffer is not released + * then -ETIMEDOUT error is returned. + * If the buffer with file descriptor @fd does not exist or has already + * been released, then -ENOENT is returned. For valid file descriptors + * this must not be treated as error. + */ +#define IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED \ + _IOC(_IOC_NONE, 'G', 10, \ + sizeof(struct ioctl_gntdev_dmabuf_exp_wait_released)) +struct ioctl_gntdev_dmabuf_exp_wait_released { + /* IN parameters */ + __u32 fd; + __u32 wait_to_ms; +}; + +/* + * Import a dma-buf with file descriptor @fd and export granted references + * to the pages of that dma-buf into array @refs of size @count. + */ +#define IOCTL_GNTDEV_DMABUF_IMP_TO_REFS \ + _IOC(_IOC_NONE, 'G', 11, \ + sizeof(struct ioctl_gntdev_dmabuf_imp_to_refs)) +struct ioctl_gntdev_dmabuf_imp_to_refs { + /* IN parameters. */ + /* File descriptor of the dma-buf. */ + __u32 fd; + /* Number of grant references in @refs array. */ + __u32 count; + /* The domain ID for which references to be granted. */ + __u32 domid; + /* Reserved - must be zero. */ + __u32 reserved; + /* OUT parameters. */ + /* Array of grant references of size @count. */ + __u32 refs[1]; +}; + +/* + * This will close all references to an imported buffer, so it can be + * released by the owner. This is only valid for buffers created with + * IOCTL_GNTDEV_DMABUF_IMP_TO_REFS. + */ +#define IOCTL_GNTDEV_DMABUF_IMP_RELEASE \ + _IOC(_IOC_NONE, 'G', 12, \ + sizeof(struct ioctl_gntdev_dmabuf_imp_release)) +struct ioctl_gntdev_dmabuf_imp_release { + /* IN parameters */ + __u32 fd; + __u32 reserved; +}; + #endif /* __LINUX_PUBLIC_GNTDEV_H__ */ diff --git a/include/xen/gntdev_exp.h b/include/xen/gntdev_exp.h new file mode 100644 index 000000000000..aaf45bda30ac --- /dev/null +++ b/include/xen/gntdev_exp.h @@ -0,0 +1,23 @@ +/****************************************************************************** + * Xen grant device exported functionality + */ + +#ifndef _XEN_GNTDEV_EXP_H +#define _XEN_GNTDEV_EXP_H + +struct gntdev_priv *gntdev_alloc_context(struct device *dev); + +void gntdev_free_context(struct gntdev_priv *priv); + +int gntdev_dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags, + int count, u32 domid, u32 *refs, u32 *fd); + +int gntdev_dmabuf_exp_wait_released(struct gntdev_priv *priv, u32 fd, + int wait_to_ms); + +int gntdev_dmabuf_imp_release(struct gntdev_priv *priv, u32 fd); + +u32 *gntdev_dmabuf_imp_to_refs(struct gntdev_priv *priv, int fd, + int count, int domid, u32 **refs); + +#endif