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authorOleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>2018-07-20 12:01:48 +0300
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2018-07-27 06:05:14 +0300
commit932d6562179efe8e2460a0343dbe0fcacf288a9e (patch)
treeedaf27dad5042f971a9f098ca7c6217132e4d08c /include/uapi/xen
parent1d314567553883d9f606cc59e8e66f465a4b6ccd (diff)
downloadlinux-932d6562179efe8e2460a0343dbe0fcacf288a9e.tar.xz
xen/gntdev: Add initial support for dma-buf UAPI
Add UAPI and IOCTLs for dma-buf grant device driver extension: the extension allows userspace processes and kernel modules to use Xen backed dma-buf implementation. With this extension grant references to the pages of an imported dma-buf can be exported for other domain use and grant references coming from a foreign domain can be converted into a local dma-buf for local export. Implement basic initialization and stubs for Xen DMA buffers' support. Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'include/uapi/xen')
-rw-r--r--include/uapi/xen/gntdev.h91
1 files changed, 91 insertions, 0 deletions
diff --git a/include/uapi/xen/gntdev.h b/include/uapi/xen/gntdev.h
index 4b9d498a31d4..fe4423e518c6 100644
--- a/include/uapi/xen/gntdev.h
+++ b/include/uapi/xen/gntdev.h
@@ -5,6 +5,7 @@
* Interface to /dev/xen/gntdev.
*
* Copyright (c) 2007, D G Murray
+ * Copyright (c) 2018, Oleksandr Andrushchenko, EPAM Systems Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
@@ -215,4 +216,94 @@ struct ioctl_gntdev_grant_copy {
*/
#define GNTDEV_DMA_FLAG_COHERENT (1 << 1)
+/*
+ * 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
+ * one of the GNTDEV_DMA_FLAG_XXX flags it can also be created as
+ * a DMA write-combine or coherent buffer, e.g. allocated with dma_alloc_wc/
+ * dma_alloc_coherent.
+ *
+ * Returns 0 if dma-buf was successfully created and the corresponding
+ * dma-buf's file descriptor is returned in @fd.
+ *
+ * [1] Documentation/driver-api/dma-buf.rst
+ */
+
+#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_DMA_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 within @wait_to_ms milliseconds the buffer is not released
+ * then -ETIMEDOUT error is returned.
+ * If the buffer with the 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 the imported buffer with file descriptor
+ * @fd, 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__ */