bdc612dc69
This ioctl allows the users of a shared page to be notified when the other end exits abnormally. [v2: updated description in structs] Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
83 lines
2.6 KiB
C
83 lines
2.6 KiB
C
/******************************************************************************
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* gntalloc.h
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*
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* Interface to /dev/xen/gntalloc.
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*
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* Author: Daniel De Graaf <dgdegra@tycho.nsa.gov>
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*
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* This file is in the public domain.
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*/
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#ifndef __LINUX_PUBLIC_GNTALLOC_H__
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#define __LINUX_PUBLIC_GNTALLOC_H__
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/*
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* Allocates a new page and creates a new grant reference.
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*/
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#define IOCTL_GNTALLOC_ALLOC_GREF \
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_IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref))
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struct ioctl_gntalloc_alloc_gref {
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/* IN parameters */
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/* The ID of the domain to be given access to the grants. */
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uint16_t domid;
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/* Flags for this mapping */
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uint16_t flags;
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/* Number of pages to map */
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uint32_t count;
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/* OUT parameters */
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/* The offset to be used on a subsequent call to mmap(). */
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uint64_t index;
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/* The grant references of the newly created grant, one per page */
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/* Variable size, depending on count */
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uint32_t gref_ids[1];
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};
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#define GNTALLOC_FLAG_WRITABLE 1
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/*
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* Deallocates the grant reference, allowing the associated page to be freed if
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* no other domains are using it.
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*/
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#define IOCTL_GNTALLOC_DEALLOC_GREF \
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_IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref))
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struct ioctl_gntalloc_dealloc_gref {
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/* IN parameters */
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/* The offset returned in the map operation */
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uint64_t index;
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/* Number of references to unmap */
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uint32_t count;
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};
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/*
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* Sets up an unmap notification within the page, so that the other side can do
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* cleanup if this side crashes. Required to implement cross-domain robust
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* mutexes or close notification on communication channels.
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*
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* Each mapped page only supports one notification; multiple calls referring to
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* the same page overwrite the previous notification. You must clear the
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* notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
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* to occur.
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*/
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#define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \
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_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify))
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struct ioctl_gntalloc_unmap_notify {
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/* IN parameters */
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/* Offset in the file descriptor for a byte within the page (same as
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* used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
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* be cleared. Otherwise, it can be any byte in the page whose
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* notification we are adjusting.
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*/
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uint64_t index;
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/* Action(s) to take on unmap */
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uint32_t action;
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/* Event channel to notify */
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uint32_t event_channel_port;
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};
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/* Clear (set to zero) the byte specified by index */
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#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
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/* Send an interrupt on the indicated event channel */
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#define UNMAP_NOTIFY_SEND_EVENT 0x2
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#endif /* __LINUX_PUBLIC_GNTALLOC_H__ */
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