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@@ -0,0 +1,857 @@
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+// SPDX-License-Identifier: GPL-2.0
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+
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+/*
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+ * Xen dma-buf functionality for gntdev.
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+ *
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+ * DMA buffer implementation is based on drivers/gpu/drm/drm_prime.c.
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+ *
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+ * Copyright (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
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+ */
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+
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+#include <linux/kernel.h>
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+#include <linux/errno.h>
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+#include <linux/dma-buf.h>
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+#include <linux/slab.h>
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+#include <linux/types.h>
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+#include <linux/uaccess.h>
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+
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+#include <xen/xen.h>
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+#include <xen/grant_table.h>
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+
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+#include "gntdev-common.h"
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+#include "gntdev-dmabuf.h"
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+
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+#ifndef GRANT_INVALID_REF
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+/*
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+ * Note on usage of grant reference 0 as invalid grant reference:
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+ * grant reference 0 is valid, but never exposed to a driver,
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+ * because of the fact it is already in use/reserved by the PV console.
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+ */
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+#define GRANT_INVALID_REF 0
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+#endif
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+
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+struct gntdev_dmabuf {
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+ struct gntdev_dmabuf_priv *priv;
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+ struct dma_buf *dmabuf;
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+ struct list_head next;
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+ int fd;
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+
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+ union {
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+ struct {
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+ /* Exported buffers are reference counted. */
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+ struct kref refcount;
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+
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+ struct gntdev_priv *priv;
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+ struct gntdev_grant_map *map;
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+ } exp;
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+ struct {
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+ /* Granted references of the imported buffer. */
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+ grant_ref_t *refs;
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+ /* Scatter-gather table of the imported buffer. */
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+ struct sg_table *sgt;
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+ /* dma-buf attachment of the imported buffer. */
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+ struct dma_buf_attachment *attach;
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+ } imp;
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+ } u;
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+
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+ /* Number of pages this buffer has. */
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+ int nr_pages;
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+ /* Pages of this buffer. */
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+ struct page **pages;
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+};
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+
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+struct gntdev_dmabuf_wait_obj {
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+ struct list_head next;
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+ struct gntdev_dmabuf *gntdev_dmabuf;
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+ struct completion completion;
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+};
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+
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+struct gntdev_dmabuf_attachment {
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+ struct sg_table *sgt;
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+ enum dma_data_direction dir;
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+};
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+
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+struct gntdev_dmabuf_priv {
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+ /* List of exported DMA buffers. */
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+ struct list_head exp_list;
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+ /* List of wait objects. */
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+ struct list_head exp_wait_list;
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+ /* List of imported DMA buffers. */
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+ struct list_head imp_list;
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+ /* This is the lock which protects dma_buf_xxx lists. */
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+ struct mutex lock;
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+};
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+
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+/* DMA buffer export support. */
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+
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+/* Implementation of wait for exported DMA buffer to be released. */
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+
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+static void dmabuf_exp_release(struct kref *kref);
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+
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+static struct gntdev_dmabuf_wait_obj *
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+dmabuf_exp_wait_obj_new(struct gntdev_dmabuf_priv *priv,
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+ struct gntdev_dmabuf *gntdev_dmabuf)
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+{
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+ struct gntdev_dmabuf_wait_obj *obj;
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+
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+ obj = kzalloc(sizeof(*obj), GFP_KERNEL);
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+ if (!obj)
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+ return ERR_PTR(-ENOMEM);
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+
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+ init_completion(&obj->completion);
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+ obj->gntdev_dmabuf = gntdev_dmabuf;
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+
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+ mutex_lock(&priv->lock);
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+ list_add(&obj->next, &priv->exp_wait_list);
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+ /* Put our reference and wait for gntdev_dmabuf's release to fire. */
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+ kref_put(&gntdev_dmabuf->u.exp.refcount, dmabuf_exp_release);
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+ mutex_unlock(&priv->lock);
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+ return obj;
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+}
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+
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+static void dmabuf_exp_wait_obj_free(struct gntdev_dmabuf_priv *priv,
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+ struct gntdev_dmabuf_wait_obj *obj)
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+{
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+ mutex_lock(&priv->lock);
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+ list_del(&obj->next);
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+ mutex_unlock(&priv->lock);
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+ kfree(obj);
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+}
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+
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+static int dmabuf_exp_wait_obj_wait(struct gntdev_dmabuf_wait_obj *obj,
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+ u32 wait_to_ms)
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+{
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+ if (wait_for_completion_timeout(&obj->completion,
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+ msecs_to_jiffies(wait_to_ms)) <= 0)
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+ return -ETIMEDOUT;
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+
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+ return 0;
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+}
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+
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+static void dmabuf_exp_wait_obj_signal(struct gntdev_dmabuf_priv *priv,
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+ struct gntdev_dmabuf *gntdev_dmabuf)
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+{
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+ struct gntdev_dmabuf_wait_obj *obj;
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+
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+ list_for_each_entry(obj, &priv->exp_wait_list, next)
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+ if (obj->gntdev_dmabuf == gntdev_dmabuf) {
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+ pr_debug("Found gntdev_dmabuf in the wait list, wake\n");
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+ complete_all(&obj->completion);
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+ break;
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+ }
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+}
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+
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+static struct gntdev_dmabuf *
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+dmabuf_exp_wait_obj_get_dmabuf(struct gntdev_dmabuf_priv *priv, int fd)
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+{
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+ struct gntdev_dmabuf *gntdev_dmabuf, *ret = ERR_PTR(-ENOENT);
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+
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+ mutex_lock(&priv->lock);
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+ list_for_each_entry(gntdev_dmabuf, &priv->exp_list, next)
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+ if (gntdev_dmabuf->fd == fd) {
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+ pr_debug("Found gntdev_dmabuf in the wait list\n");
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+ kref_get(&gntdev_dmabuf->u.exp.refcount);
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+ ret = gntdev_dmabuf;
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+ break;
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+ }
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+ mutex_unlock(&priv->lock);
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+ return ret;
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+}
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+
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+static int dmabuf_exp_wait_released(struct gntdev_dmabuf_priv *priv, int fd,
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+ int wait_to_ms)
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+{
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+ struct gntdev_dmabuf *gntdev_dmabuf;
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+ struct gntdev_dmabuf_wait_obj *obj;
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+ int ret;
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+
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+ pr_debug("Will wait for dma-buf with fd %d\n", fd);
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+ /*
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+ * Try to find the DMA buffer: if not found means that
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+ * either the buffer has already been released or file descriptor
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+ * provided is wrong.
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+ */
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+ gntdev_dmabuf = dmabuf_exp_wait_obj_get_dmabuf(priv, fd);
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+ if (IS_ERR(gntdev_dmabuf))
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+ return PTR_ERR(gntdev_dmabuf);
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+
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+ /*
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+ * gntdev_dmabuf still exists and is reference count locked by us now,
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+ * so prepare to wait: allocate wait object and add it to the wait list,
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+ * so we can find it on release.
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+ */
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+ obj = dmabuf_exp_wait_obj_new(priv, gntdev_dmabuf);
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+ if (IS_ERR(obj))
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+ return PTR_ERR(obj);
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+
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+ ret = dmabuf_exp_wait_obj_wait(obj, wait_to_ms);
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+ dmabuf_exp_wait_obj_free(priv, obj);
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+ return ret;
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+}
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+
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+/* DMA buffer export support. */
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+
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+static struct sg_table *
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+dmabuf_pages_to_sgt(struct page **pages, unsigned int nr_pages)
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+{
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+ struct sg_table *sgt;
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+ int ret;
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+
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+ sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
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+ if (!sgt) {
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+ ret = -ENOMEM;
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+ goto out;
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+ }
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+
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+ ret = sg_alloc_table_from_pages(sgt, pages, nr_pages, 0,
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+ nr_pages << PAGE_SHIFT,
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+ GFP_KERNEL);
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+ if (ret)
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+ goto out;
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+
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+ return sgt;
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+
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+out:
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+ kfree(sgt);
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+ return ERR_PTR(ret);
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+}
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+
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+static int dmabuf_exp_ops_attach(struct dma_buf *dma_buf,
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+ struct device *target_dev,
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+ struct dma_buf_attachment *attach)
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+{
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+ struct gntdev_dmabuf_attachment *gntdev_dmabuf_attach;
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+
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+ gntdev_dmabuf_attach = kzalloc(sizeof(*gntdev_dmabuf_attach),
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+ GFP_KERNEL);
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+ if (!gntdev_dmabuf_attach)
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+ return -ENOMEM;
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+
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+ gntdev_dmabuf_attach->dir = DMA_NONE;
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+ attach->priv = gntdev_dmabuf_attach;
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+ return 0;
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+}
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+
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+static void dmabuf_exp_ops_detach(struct dma_buf *dma_buf,
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+ struct dma_buf_attachment *attach)
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+{
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+ struct gntdev_dmabuf_attachment *gntdev_dmabuf_attach = attach->priv;
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+
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+ if (gntdev_dmabuf_attach) {
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+ struct sg_table *sgt = gntdev_dmabuf_attach->sgt;
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+
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+ if (sgt) {
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+ if (gntdev_dmabuf_attach->dir != DMA_NONE)
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+ dma_unmap_sg_attrs(attach->dev, sgt->sgl,
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+ sgt->nents,
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+ gntdev_dmabuf_attach->dir,
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+ DMA_ATTR_SKIP_CPU_SYNC);
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+ sg_free_table(sgt);
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+ }
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+
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+ kfree(sgt);
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+ kfree(gntdev_dmabuf_attach);
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+ attach->priv = NULL;
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+ }
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+}
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+
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+static struct sg_table *
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+dmabuf_exp_ops_map_dma_buf(struct dma_buf_attachment *attach,
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+ enum dma_data_direction dir)
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+{
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+ struct gntdev_dmabuf_attachment *gntdev_dmabuf_attach = attach->priv;
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+ struct gntdev_dmabuf *gntdev_dmabuf = attach->dmabuf->priv;
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+ struct sg_table *sgt;
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+
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+ pr_debug("Mapping %d pages for dev %p\n", gntdev_dmabuf->nr_pages,
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+ attach->dev);
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+
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+ if (dir == DMA_NONE || !gntdev_dmabuf_attach)
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+ return ERR_PTR(-EINVAL);
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+
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+ /* Return the cached mapping when possible. */
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+ if (gntdev_dmabuf_attach->dir == dir)
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+ return gntdev_dmabuf_attach->sgt;
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+
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+ /*
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+ * Two mappings with different directions for the same attachment are
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+ * not allowed.
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+ */
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+ if (gntdev_dmabuf_attach->dir != DMA_NONE)
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+ return ERR_PTR(-EBUSY);
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+
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+ sgt = dmabuf_pages_to_sgt(gntdev_dmabuf->pages,
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+ gntdev_dmabuf->nr_pages);
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+ if (!IS_ERR(sgt)) {
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+ if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
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+ DMA_ATTR_SKIP_CPU_SYNC)) {
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+ sg_free_table(sgt);
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+ kfree(sgt);
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+ sgt = ERR_PTR(-ENOMEM);
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+ } else {
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+ gntdev_dmabuf_attach->sgt = sgt;
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+ gntdev_dmabuf_attach->dir = dir;
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+ }
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+ }
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+ if (IS_ERR(sgt))
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+ pr_debug("Failed to map sg table for dev %p\n", attach->dev);
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+ return sgt;
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+}
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+
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+static void dmabuf_exp_ops_unmap_dma_buf(struct dma_buf_attachment *attach,
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+ struct sg_table *sgt,
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+ enum dma_data_direction dir)
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+{
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+ /* Not implemented. The unmap is done at dmabuf_exp_ops_detach(). */
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+}
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+
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+static void dmabuf_exp_release(struct kref *kref)
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+{
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+ struct gntdev_dmabuf *gntdev_dmabuf =
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+ container_of(kref, struct gntdev_dmabuf, u.exp.refcount);
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+
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+ dmabuf_exp_wait_obj_signal(gntdev_dmabuf->priv, gntdev_dmabuf);
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+ list_del(&gntdev_dmabuf->next);
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+ kfree(gntdev_dmabuf);
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+}
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+
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+static void dmabuf_exp_remove_map(struct gntdev_priv *priv,
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+ struct gntdev_grant_map *map)
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+{
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+ mutex_lock(&priv->lock);
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+ list_del(&map->next);
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+ gntdev_put_map(NULL /* already removed */, map);
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+ mutex_unlock(&priv->lock);
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+}
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+
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+static void dmabuf_exp_ops_release(struct dma_buf *dma_buf)
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+{
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+ struct gntdev_dmabuf *gntdev_dmabuf = dma_buf->priv;
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+ struct gntdev_dmabuf_priv *priv = gntdev_dmabuf->priv;
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+
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+ dmabuf_exp_remove_map(gntdev_dmabuf->u.exp.priv,
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+ gntdev_dmabuf->u.exp.map);
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+ mutex_lock(&priv->lock);
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+ kref_put(&gntdev_dmabuf->u.exp.refcount, dmabuf_exp_release);
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+ mutex_unlock(&priv->lock);
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+}
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+
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+static void *dmabuf_exp_ops_kmap(struct dma_buf *dma_buf,
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+ unsigned long page_num)
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+{
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+ /* Not implemented. */
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+ return NULL;
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+}
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+
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+static void dmabuf_exp_ops_kunmap(struct dma_buf *dma_buf,
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+ unsigned long page_num, void *addr)
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+{
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+ /* Not implemented. */
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+}
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+
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+static int dmabuf_exp_ops_mmap(struct dma_buf *dma_buf,
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+ struct vm_area_struct *vma)
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+{
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+ /* Not implemented. */
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+ return 0;
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+}
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+
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+static const struct dma_buf_ops dmabuf_exp_ops = {
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+ .attach = dmabuf_exp_ops_attach,
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+ .detach = dmabuf_exp_ops_detach,
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+ .map_dma_buf = dmabuf_exp_ops_map_dma_buf,
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+ .unmap_dma_buf = dmabuf_exp_ops_unmap_dma_buf,
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+ .release = dmabuf_exp_ops_release,
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+ .map = dmabuf_exp_ops_kmap,
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+ .unmap = dmabuf_exp_ops_kunmap,
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+ .mmap = dmabuf_exp_ops_mmap,
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+};
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+
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+struct gntdev_dmabuf_export_args {
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+ struct gntdev_priv *priv;
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+ struct gntdev_grant_map *map;
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+ struct gntdev_dmabuf_priv *dmabuf_priv;
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+ struct device *dev;
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+ int count;
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+ struct page **pages;
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+ u32 fd;
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+};
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+
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+static int dmabuf_exp_from_pages(struct gntdev_dmabuf_export_args *args)
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+{
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+ DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
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+ struct gntdev_dmabuf *gntdev_dmabuf;
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+ int ret;
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+
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+ gntdev_dmabuf = kzalloc(sizeof(*gntdev_dmabuf), GFP_KERNEL);
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+ if (!gntdev_dmabuf)
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+ return -ENOMEM;
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+
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+ kref_init(&gntdev_dmabuf->u.exp.refcount);
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+
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+ gntdev_dmabuf->priv = args->dmabuf_priv;
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+ gntdev_dmabuf->nr_pages = args->count;
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+ gntdev_dmabuf->pages = args->pages;
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+ gntdev_dmabuf->u.exp.priv = args->priv;
|
|
|
+ gntdev_dmabuf->u.exp.map = args->map;
|
|
|
+
|
|
|
+ exp_info.exp_name = KBUILD_MODNAME;
|
|
|
+ if (args->dev->driver && args->dev->driver->owner)
|
|
|
+ exp_info.owner = args->dev->driver->owner;
|
|
|
+ else
|
|
|
+ exp_info.owner = THIS_MODULE;
|
|
|
+ exp_info.ops = &dmabuf_exp_ops;
|
|
|
+ exp_info.size = args->count << PAGE_SHIFT;
|
|
|
+ exp_info.flags = O_RDWR;
|
|
|
+ exp_info.priv = gntdev_dmabuf;
|
|
|
+
|
|
|
+ gntdev_dmabuf->dmabuf = dma_buf_export(&exp_info);
|
|
|
+ if (IS_ERR(gntdev_dmabuf->dmabuf)) {
|
|
|
+ ret = PTR_ERR(gntdev_dmabuf->dmabuf);
|
|
|
+ gntdev_dmabuf->dmabuf = NULL;
|
|
|
+ goto fail;
|
|
|
+ }
|
|
|
+
|
|
|
+ ret = dma_buf_fd(gntdev_dmabuf->dmabuf, O_CLOEXEC);
|
|
|
+ if (ret < 0)
|
|
|
+ goto fail;
|
|
|
+
|
|
|
+ gntdev_dmabuf->fd = ret;
|
|
|
+ args->fd = ret;
|
|
|
+
|
|
|
+ pr_debug("Exporting DMA buffer with fd %d\n", ret);
|
|
|
+
|
|
|
+ mutex_lock(&args->dmabuf_priv->lock);
|
|
|
+ list_add(&gntdev_dmabuf->next, &args->dmabuf_priv->exp_list);
|
|
|
+ mutex_unlock(&args->dmabuf_priv->lock);
|
|
|
+ return 0;
|
|
|
+
|
|
|
+fail:
|
|
|
+ if (gntdev_dmabuf->dmabuf)
|
|
|
+ dma_buf_put(gntdev_dmabuf->dmabuf);
|
|
|
+ kfree(gntdev_dmabuf);
|
|
|
+ return ret;
|
|
|
+}
|
|
|
+
|
|
|
+static struct gntdev_grant_map *
|
|
|
+dmabuf_exp_alloc_backing_storage(struct gntdev_priv *priv, int dmabuf_flags,
|
|
|
+ int count)
|
|
|
+{
|
|
|
+ struct gntdev_grant_map *map;
|
|
|
+
|
|
|
+ if (unlikely(count <= 0))
|
|
|
+ return ERR_PTR(-EINVAL);
|
|
|
+
|
|
|
+ if ((dmabuf_flags & GNTDEV_DMA_FLAG_WC) &&
|
|
|
+ (dmabuf_flags & GNTDEV_DMA_FLAG_COHERENT)) {
|
|
|
+ pr_debug("Wrong dma-buf flags: 0x%x\n", dmabuf_flags);
|
|
|
+ return ERR_PTR(-EINVAL);
|
|
|
+ }
|
|
|
+
|
|
|
+ map = gntdev_alloc_map(priv, count, dmabuf_flags);
|
|
|
+ if (!map)
|
|
|
+ return ERR_PTR(-ENOMEM);
|
|
|
+
|
|
|
+ if (unlikely(gntdev_account_mapped_pages(count))) {
|
|
|
+ pr_debug("can't map %d pages: over limit\n", count);
|
|
|
+ gntdev_put_map(NULL, map);
|
|
|
+ return ERR_PTR(-ENOMEM);
|
|
|
+ }
|
|
|
+ return map;
|
|
|
+}
|
|
|
+
|
|
|
+static int dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags,
|
|
|
+ int count, u32 domid, u32 *refs, u32 *fd)
|
|
|
+{
|
|
|
+ struct gntdev_grant_map *map;
|
|
|
+ struct gntdev_dmabuf_export_args args;
|
|
|
+ int i, ret;
|
|
|
+
|
|
|
+ map = dmabuf_exp_alloc_backing_storage(priv, 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 = gntdev_map_grant_pages(map);
|
|
|
+ if (ret < 0)
|
|
|
+ goto out;
|
|
|
+
|
|
|
+ args.priv = priv;
|
|
|
+ args.map = map;
|
|
|
+ args.dev = priv->dma_dev;
|
|
|
+ args.dmabuf_priv = priv->dmabuf_priv;
|
|
|
+ args.count = map->count;
|
|
|
+ args.pages = map->pages;
|
|
|
+ args.fd = -1; /* Shut up unnecessary gcc warning for i386 */
|
|
|
+
|
|
|
+ ret = dmabuf_exp_from_pages(&args);
|
|
|
+ if (ret < 0)
|
|
|
+ goto out;
|
|
|
+
|
|
|
+ *fd = args.fd;
|
|
|
+ return 0;
|
|
|
+
|
|
|
+out:
|
|
|
+ dmabuf_exp_remove_map(priv, map);
|
|
|
+ return ret;
|
|
|
+}
|
|
|
+
|
|
|
+/* 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_debug("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_debug("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;
|
|
|
+ }
|
|
|
+
|
|
|
+ return 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 gntdev_dmabuf *gntdev_dmabuf)
|
|
|
+{
|
|
|
+ kfree(gntdev_dmabuf->pages);
|
|
|
+ kfree(gntdev_dmabuf->u.imp.refs);
|
|
|
+ kfree(gntdev_dmabuf);
|
|
|
+}
|
|
|
+
|
|
|
+static struct gntdev_dmabuf *dmabuf_imp_alloc_storage(int count)
|
|
|
+{
|
|
|
+ struct gntdev_dmabuf *gntdev_dmabuf;
|
|
|
+ int i;
|
|
|
+
|
|
|
+ gntdev_dmabuf = kzalloc(sizeof(*gntdev_dmabuf), GFP_KERNEL);
|
|
|
+ if (!gntdev_dmabuf)
|
|
|
+ goto fail_no_free;
|
|
|
+
|
|
|
+ gntdev_dmabuf->u.imp.refs = kcalloc(count,
|
|
|
+ sizeof(gntdev_dmabuf->u.imp.refs[0]),
|
|
|
+ GFP_KERNEL);
|
|
|
+ if (!gntdev_dmabuf->u.imp.refs)
|
|
|
+ goto fail;
|
|
|
+
|
|
|
+ gntdev_dmabuf->pages = kcalloc(count,
|
|
|
+ sizeof(gntdev_dmabuf->pages[0]),
|
|
|
+ GFP_KERNEL);
|
|
|
+ if (!gntdev_dmabuf->pages)
|
|
|
+ goto fail;
|
|
|
+
|
|
|
+ gntdev_dmabuf->nr_pages = count;
|
|
|
+
|
|
|
+ for (i = 0; i < count; i++)
|
|
|
+ gntdev_dmabuf->u.imp.refs[i] = GRANT_INVALID_REF;
|
|
|
+
|
|
|
+ return gntdev_dmabuf;
|
|
|
+
|
|
|
+fail:
|
|
|
+ dmabuf_imp_free_storage(gntdev_dmabuf);
|
|
|
+fail_no_free:
|
|
|
+ return ERR_PTR(-ENOMEM);
|
|
|
+}
|
|
|
+
|
|
|
+static struct gntdev_dmabuf *
|
|
|
+dmabuf_imp_to_refs(struct gntdev_dmabuf_priv *priv, struct device *dev,
|
|
|
+ int fd, int count, int domid)
|
|
|
+{
|
|
|
+ struct gntdev_dmabuf *gntdev_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);
|
|
|
+
|
|
|
+ gntdev_dmabuf = dmabuf_imp_alloc_storage(count);
|
|
|
+ if (IS_ERR(gntdev_dmabuf)) {
|
|
|
+ ret = gntdev_dmabuf;
|
|
|
+ goto fail_put;
|
|
|
+ }
|
|
|
+
|
|
|
+ gntdev_dmabuf->priv = priv;
|
|
|
+ gntdev_dmabuf->fd = fd;
|
|
|
+
|
|
|
+ attach = dma_buf_attach(dma_buf, dev);
|
|
|
+ if (IS_ERR(attach)) {
|
|
|
+ ret = ERR_CAST(attach);
|
|
|
+ goto fail_free_obj;
|
|
|
+ }
|
|
|
+
|
|
|
+ gntdev_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 != gntdev_dmabuf->nr_pages << PAGE_SHIFT) {
|
|
|
+ ret = ERR_PTR(-EINVAL);
|
|
|
+ pr_debug("DMA buffer has %zu pages, user-space expects %d\n",
|
|
|
+ attach->dmabuf->size, gntdev_dmabuf->nr_pages);
|
|
|
+ goto fail_unmap;
|
|
|
+ }
|
|
|
+
|
|
|
+ gntdev_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;
|
|
|
+ }
|
|
|
+
|
|
|
+ gntdev_dmabuf->pages[i++] = page;
|
|
|
+ }
|
|
|
+
|
|
|
+ ret = ERR_PTR(dmabuf_imp_grant_foreign_access(gntdev_dmabuf->pages,
|
|
|
+ gntdev_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->lock);
|
|
|
+ list_add(&gntdev_dmabuf->next, &priv->imp_list);
|
|
|
+ mutex_unlock(&priv->lock);
|
|
|
+
|
|
|
+ return gntdev_dmabuf;
|
|
|
+
|
|
|
+fail_end_access:
|
|
|
+ dmabuf_imp_end_foreign_access(gntdev_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(gntdev_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 gntdev_dmabuf *
|
|
|
+dmabuf_imp_find_unlink(struct gntdev_dmabuf_priv *priv, int fd)
|
|
|
+{
|
|
|
+ struct gntdev_dmabuf *q, *gntdev_dmabuf, *ret = ERR_PTR(-ENOENT);
|
|
|
+
|
|
|
+ mutex_lock(&priv->lock);
|
|
|
+ list_for_each_entry_safe(gntdev_dmabuf, q, &priv->imp_list, next) {
|
|
|
+ if (gntdev_dmabuf->fd == fd) {
|
|
|
+ pr_debug("Found gntdev_dmabuf in the import list\n");
|
|
|
+ ret = gntdev_dmabuf;
|
|
|
+ list_del(&gntdev_dmabuf->next);
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ mutex_unlock(&priv->lock);
|
|
|
+ return ret;
|
|
|
+}
|
|
|
+
|
|
|
+static int dmabuf_imp_release(struct gntdev_dmabuf_priv *priv, u32 fd)
|
|
|
+{
|
|
|
+ struct gntdev_dmabuf *gntdev_dmabuf;
|
|
|
+ struct dma_buf_attachment *attach;
|
|
|
+ struct dma_buf *dma_buf;
|
|
|
+
|
|
|
+ gntdev_dmabuf = dmabuf_imp_find_unlink(priv, fd);
|
|
|
+ if (IS_ERR(gntdev_dmabuf))
|
|
|
+ return PTR_ERR(gntdev_dmabuf);
|
|
|
+
|
|
|
+ pr_debug("Releasing DMA buffer with fd %d\n", fd);
|
|
|
+
|
|
|
+ dmabuf_imp_end_foreign_access(gntdev_dmabuf->u.imp.refs,
|
|
|
+ gntdev_dmabuf->nr_pages);
|
|
|
+
|
|
|
+ attach = gntdev_dmabuf->u.imp.attach;
|
|
|
+
|
|
|
+ if (gntdev_dmabuf->u.imp.sgt)
|
|
|
+ dma_buf_unmap_attachment(attach, gntdev_dmabuf->u.imp.sgt,
|
|
|
+ DMA_BIDIRECTIONAL);
|
|
|
+ dma_buf = attach->dmabuf;
|
|
|
+ dma_buf_detach(attach->dmabuf, attach);
|
|
|
+ dma_buf_put(dma_buf);
|
|
|
+
|
|
|
+ dmabuf_imp_free_storage(gntdev_dmabuf);
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+
|
|
|
+/* DMA buffer IOCTL support. */
|
|
|
+
|
|
|
+long gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv, int use_ptemod,
|
|
|
+ struct ioctl_gntdev_dmabuf_exp_from_refs __user *u)
|
|
|
+{
|
|
|
+ struct ioctl_gntdev_dmabuf_exp_from_refs op;
|
|
|
+ u32 *refs;
|
|
|
+ long ret;
|
|
|
+
|
|
|
+ if (use_ptemod) {
|
|
|
+ pr_debug("Cannot provide dma-buf: use_ptemode %d\n",
|
|
|
+ use_ptemod);
|
|
|
+ return -EINVAL;
|
|
|
+ }
|
|
|
+
|
|
|
+ if (copy_from_user(&op, u, sizeof(op)) != 0)
|
|
|
+ return -EFAULT;
|
|
|
+
|
|
|
+ if (unlikely(op.count <= 0))
|
|
|
+ return -EINVAL;
|
|
|
+
|
|
|
+ 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 = 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;
|
|
|
+}
|
|
|
+
|
|
|
+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->dmabuf_priv, op.fd,
|
|
|
+ op.wait_to_ms);
|
|
|
+}
|
|
|
+
|
|
|
+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 gntdev_dmabuf *gntdev_dmabuf;
|
|
|
+ long ret;
|
|
|
+
|
|
|
+ if (copy_from_user(&op, u, sizeof(op)) != 0)
|
|
|
+ return -EFAULT;
|
|
|
+
|
|
|
+ if (unlikely(op.count <= 0))
|
|
|
+ return -EINVAL;
|
|
|
+
|
|
|
+ gntdev_dmabuf = dmabuf_imp_to_refs(priv->dmabuf_priv,
|
|
|
+ priv->dma_dev, op.fd,
|
|
|
+ op.count, op.domid);
|
|
|
+ if (IS_ERR(gntdev_dmabuf))
|
|
|
+ return PTR_ERR(gntdev_dmabuf);
|
|
|
+
|
|
|
+ if (copy_to_user(u->refs, gntdev_dmabuf->u.imp.refs,
|
|
|
+ sizeof(*u->refs) * op.count) != 0) {
|
|
|
+ ret = -EFAULT;
|
|
|
+ goto out_release;
|
|
|
+ }
|
|
|
+ return 0;
|
|
|
+
|
|
|
+out_release:
|
|
|
+ dmabuf_imp_release(priv->dmabuf_priv, op.fd);
|
|
|
+ return ret;
|
|
|
+}
|
|
|
+
|
|
|
+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 dmabuf_imp_release(priv->dmabuf_priv, op.fd);
|
|
|
+}
|
|
|
+
|
|
|
+struct gntdev_dmabuf_priv *gntdev_dmabuf_init(void)
|
|
|
+{
|
|
|
+ struct gntdev_dmabuf_priv *priv;
|
|
|
+
|
|
|
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
|
|
|
+ if (!priv)
|
|
|
+ return ERR_PTR(-ENOMEM);
|
|
|
+
|
|
|
+ mutex_init(&priv->lock);
|
|
|
+ INIT_LIST_HEAD(&priv->exp_list);
|
|
|
+ INIT_LIST_HEAD(&priv->exp_wait_list);
|
|
|
+ INIT_LIST_HEAD(&priv->imp_list);
|
|
|
+
|
|
|
+ return priv;
|
|
|
+}
|
|
|
+
|
|
|
+void gntdev_dmabuf_fini(struct gntdev_dmabuf_priv *priv)
|
|
|
+{
|
|
|
+ kfree(priv);
|
|
|
+}
|
Linus Torvalds