/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR MIT) */
/******************************************************************************
* gntdev.h
*
* 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
* as published by the Free Software Foundation; or, when distributed
* separately from the Linux kernel or incorporated into other
* software packages, subject to the following license:
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this source file (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy, modify,
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#ifndef __LINUX_PUBLIC_GNTDEV_H__
#define __LINUX_PUBLIC_GNTDEV_H__
#include <linux/types.h>
struct ioctl_gntdev_grant_ref {
/* The domain ID of the grant to be mapped. */
__u32 domid;
/* The grant reference of the grant to be mapped. */
__u32 ref;
};
/*
* Inserts the grant references into the mapping table of an instance
* of gntdev. N.B. This does not perform the mapping, which is deferred
* until mmap() is called with @index as the offset. @index should be
* considered opaque to userspace, with one exception: if no grant
* references have ever been inserted into the mapping table of this
* instance, @index will be set to 0. This is necessary to use gntdev
* with userspace APIs that expect a file descriptor that can be
* mmap()'d at offset 0, such as Wayland. If @count is set to 0, this
* ioctl will fail.
*/
#define IOCTL_GNTDEV_MAP_GRANT_REF \
_IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
struct ioctl_gntdev_map_grant_ref {
/* IN parameters */
/* The number of grants to be mapped. */
__u32 count;
__u32 pad;
/* OUT parameters */
/* The offset to be used on a subsequent call to mmap(). */
__u64 index;
/* Variable IN parameter. */
/* Array of grant references, of size @count. */
struct ioctl_gntdev_grant_ref refs[1];
};
/*
* Removes the grant references from the mapping table of an instance of
* gntdev. N.B. munmap() must be called on the relevant virtual address(es)
* before this ioctl is called, or an error will result.
*/
#define IOCTL_GNTDEV_UNMAP_GRANT_REF \
_IOC(_IOC_NONE, 'G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
struct ioctl_gntdev_unmap_grant_ref {
/* IN parameters */
/* The offset was returned by the corresponding map operation. */
__u64 index;
/* The number of pages to be unmapped. */
__u32 count;
__u32 pad;
};
/*
* Returns the offset in the driver's address space that corresponds
* to @vaddr. This can be used to perform a munmap(), followed by an
* UNMAP_GRANT_REF ioctl, where no state about the offset is retained by
* the caller. The number of pages that were allocated at the same time as
* @vaddr is returned in @count.
*
* N.B. Where more than one page has been mapped into a contiguous range, the
* supplied @vaddr must correspond to the start of the range; otherwise
* an error will result. It is only possible to munmap() the entire
* contiguously-allocated range at once, and not any subrange thereof.
*/
#define IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR \
_IOC(_IOC_NONE, 'G', 2, sizeof(struct ioctl_gntdev_get_offset_for_vaddr))
struct ioctl_gntdev_get_offset_for_vaddr {
/* IN parameters */
/* The virtual address of the first mapped page in a range. */
__u64 vaddr;
/* OUT parameters */
/* The offset that was used in the initial mmap() operation. */
__u64 offset;
/* The number of pages mapped in the VM area that begins at @vaddr. */
__u32 count;
__u32 pad;
};
/*
* Sets the maximum number of grants that may mapped at once by this gntdev
* instance.
*
* N.B. This must be called before any other ioctl is performed on the device.
*/
#define IOCTL_GNTDEV_SET_MAX_GRANTS \
_IOC(_IOC_NONE, 'G', 3, sizeof(struct ioctl_gntdev_set_max_grants))
struct ioctl_gntdev_set_max_grants {
/* IN parameter */
/* The maximum number of grants that may be mapped at once. */
__u32 count;
};
/*
* Sets up an unmap notification within the page, so that the other side can do
* cleanup if this side crashes. Required to implement cross-domain robust
* mutexes or close notification on communication channels.
*
* Each mapped page only supports one notification; multiple calls referring to
* the same page overwrite the previous notification. You must clear the
* notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
* to occur.
*/
#define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \
_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))
struct ioctl_gntdev_unmap_notify {
/* IN parameters */
/* Offset in the file descriptor for a byte within the page (same as
* used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
* be cleared. Otherwise, it can be any byte in the page whose
* notification we are adjusting.
*/
__u64 index;
/* Action(s) to take on unmap */
__u32 action;
/* Event channel to notify */
__u32 event_channel_port;
};
struct gntdev_grant_copy_segment {
union {
void *virt;
struct {
grant_ref_t ref;
__u16 offset;
domid_t domid;
} foreign;
} source, dest;
__u16 len;
__u16 flags; /* GNTCOPY_* */
__s16 status; /* GNTST_* */
};
/*
* Copy between grant references and local buffers.
*
* The copy is split into @count @segments, each of which can copy
* to/from one grant reference.
*
* Each segment is similar to struct gnttab_copy in the hypervisor ABI
* except the local buffer is specified using a virtual address
* (instead of a GFN and offset).
*
* The local buffer may cross a Xen page boundary -- the driver will
* split segments into multiple ops if required.
*
* Returns 0 if all segments have been processed and @status in each
* segment is valid. Note that one or more segments may have failed
* (status != GNTST_okay).
*
* If the driver had to split a segment into two or more ops, @status
* includes the status of the first failed op for that segment (or
* GNTST_okay if all ops were successful).
*
* If -1 is returned, the status of all segments is undefined.
*
* EINVAL: A segment has local buffers for both source and
* destination.
* EINVAL: A segment crosses the boundary of a foreign page.
* EFAULT: A segment's local buffer is not accessible.
*/
#define IOCTL_GNTDEV_GRANT_COPY \
_IOC(_IOC_NONE, 'G', 8, sizeof(struct ioctl_gntdev_grant_copy))
struct ioctl_gntdev_grant_copy {
unsigned int count;
struct gntdev_grant_copy_segment *segments;
};
/* Clear (set to zero) the byte specified by index */
#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
/* Send an interrupt on the indicated event channel */
#define UNMAP_NOTIFY_SEND_EVENT 0x2
/*
* Flags to be used while requesting memory mapping's backing storage
* to be allocated with DMA API.
*/
/*
* The buffer is backed with memory allocated with dma_alloc_wc.
*/
#define GNTDEV_DMA_FLAG_WC (1 << 0)
/*
* The buffer is backed with memory allocated with dma_alloc_coherent.
*/
#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__ */
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