1 | /****************************************************************************** |
2 | * gntalloc.h |
3 | * |
4 | * Interface to /dev/xen/gntalloc. |
5 | * |
6 | * Author: Daniel De Graaf <dgdegra@tycho.nsa.gov> |
7 | * |
8 | * This file is in the public domain. |
9 | */ |
10 | |
11 | #ifndef __LINUX_PUBLIC_GNTALLOC_H__ |
12 | #define __LINUX_PUBLIC_GNTALLOC_H__ |
13 | |
14 | #include <linux/types.h> |
15 | |
16 | /* |
17 | * Allocates a new page and creates a new grant reference. |
18 | */ |
19 | #define IOCTL_GNTALLOC_ALLOC_GREF \ |
20 | _IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref)) |
21 | struct ioctl_gntalloc_alloc_gref { |
22 | /* IN parameters */ |
23 | /* The ID of the domain to be given access to the grants. */ |
24 | __u16 domid; |
25 | /* Flags for this mapping */ |
26 | __u16 flags; |
27 | /* Number of pages to map */ |
28 | __u32 count; |
29 | /* OUT parameters */ |
30 | /* The offset to be used on a subsequent call to mmap(). */ |
31 | __u64 index; |
32 | /* The grant references of the newly created grant, one per page */ |
33 | /* Variable size, depending on count */ |
34 | __u32 gref_ids[1]; |
35 | }; |
36 | |
37 | #define GNTALLOC_FLAG_WRITABLE 1 |
38 | |
39 | /* |
40 | * Deallocates the grant reference, allowing the associated page to be freed if |
41 | * no other domains are using it. |
42 | */ |
43 | #define IOCTL_GNTALLOC_DEALLOC_GREF \ |
44 | _IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref)) |
45 | struct ioctl_gntalloc_dealloc_gref { |
46 | /* IN parameters */ |
47 | /* The offset returned in the map operation */ |
48 | __u64 index; |
49 | /* Number of references to unmap */ |
50 | __u32 count; |
51 | }; |
52 | |
53 | /* |
54 | * Sets up an unmap notification within the page, so that the other side can do |
55 | * cleanup if this side crashes. Required to implement cross-domain robust |
56 | * mutexes or close notification on communication channels. |
57 | * |
58 | * Each mapped page only supports one notification; multiple calls referring to |
59 | * the same page overwrite the previous notification. You must clear the |
60 | * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it |
61 | * to occur. |
62 | */ |
63 | #define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \ |
64 | _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify)) |
65 | struct ioctl_gntalloc_unmap_notify { |
66 | /* IN parameters */ |
67 | /* Offset in the file descriptor for a byte within the page (same as |
68 | * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to |
69 | * be cleared. Otherwise, it can be any byte in the page whose |
70 | * notification we are adjusting. |
71 | */ |
72 | __u64 index; |
73 | /* Action(s) to take on unmap */ |
74 | __u32 action; |
75 | /* Event channel to notify */ |
76 | __u32 event_channel_port; |
77 | }; |
78 | |
79 | /* Clear (set to zero) the byte specified by index */ |
80 | #define UNMAP_NOTIFY_CLEAR_BYTE 0x1 |
81 | /* Send an interrupt on the indicated event channel */ |
82 | #define UNMAP_NOTIFY_SEND_EVENT 0x2 |
83 | |
84 | #endif /* __LINUX_PUBLIC_GNTALLOC_H__ */ |
85 | |