include/uapi/xen/gntdev.h

Source file repositories/reference/linux-study-clean/include/uapi/xen/gntdev.h

File Facts

System
Linux kernel
Corpus path
include/uapi/xen/gntdev.h
Extension
.h
Size
11036 bytes
Lines
316
Domain
Repository Root And Misc
Bucket
include
Inferred role
Repository Root And Misc: implementation source
Status
source implementation candidate

Why This File Exists

Top-level or miscellaneous repository surface. Use this as map coverage unless a later manual pass promotes the file into a deeper subsystem dossier.

Dependency Surface

Detected Declarations

Annotated Snippet

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;
};

/*

Annotation

Implementation Notes