1 #ifndef _LINUX_VIRTIO_BALLOON_H
2 #define _LINUX_VIRTIO_BALLOON_H
3 /* This header is BSD licensed so anyone can use the definitions to implement
4 * compatible drivers/servers.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of IBM nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE. */
28 #include <linux/types.h>
29 #include <linux/virtio_types.h>
30 #include <linux/virtio_ids.h>
31 #include <linux/virtio_config.h>
32
33 /* The feature bitmap for virtio balloon */
34 #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */
35 #define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue */
36 #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */
37 #define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */
38 #define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */
39 #define VIRTIO_BALLOON_F_REPORTING 5 /* Page reporting virtqueue */
40
41 /* Size of a PFN in the balloon interface. */
42 #define VIRTIO_BALLOON_PFN_SHIFT 12
43
44 #define VIRTIO_BALLOON_CMD_ID_STOP 0
45 #define VIRTIO_BALLOON_CMD_ID_DONE 1
46 struct virtio_balloon_config {
47 /* Number of pages host wants Guest to give up. */
48 __le32 num_pages;
49 /* Number of pages we've actually got in balloon. */
50 __le32 actual;
51 /*
52 * Free page hint command id, readonly by guest.
53 * Was previously named free_page_report_cmd_id so we
54 * need to carry that name for legacy support.
55 */
56 union {
57 __le32 free_page_hint_cmd_id;
58 __le32 free_page_report_cmd_id; /* deprecated */
59 };
60 /* Stores PAGE_POISON if page poisoning is in use */
61 __le32 poison_val;
62 };
63
64 #define VIRTIO_BALLOON_S_SWAP_IN 0 /* Amount of memory swapped in */
65 #define VIRTIO_BALLOON_S_SWAP_OUT 1 /* Amount of memory swapped out */
66 #define VIRTIO_BALLOON_S_MAJFLT 2 /* Number of major faults */
67 #define VIRTIO_BALLOON_S_MINFLT 3 /* Number of minor faults */
68 #define VIRTIO_BALLOON_S_MEMFREE 4 /* Total amount of free memory */
69 #define VIRTIO_BALLOON_S_MEMTOT 5 /* Total amount of memory */
70 #define VIRTIO_BALLOON_S_AVAIL 6 /* Available memory as in /proc */
71 #define VIRTIO_BALLOON_S_CACHES 7 /* Disk caches */
72 #define VIRTIO_BALLOON_S_HTLB_PGALLOC 8 /* Hugetlb page allocations */
73 #define VIRTIO_BALLOON_S_HTLB_PGFAIL 9 /* Hugetlb page allocation failures */
74 #define VIRTIO_BALLOON_S_NR 10
75
76 #define VIRTIO_BALLOON_S_NAMES_WITH_PREFIX(VIRTIO_BALLOON_S_NAMES_prefix) { \
77 VIRTIO_BALLOON_S_NAMES_prefix "swap-in", \
78 VIRTIO_BALLOON_S_NAMES_prefix "swap-out", \
79 VIRTIO_BALLOON_S_NAMES_prefix "major-faults", \
80 VIRTIO_BALLOON_S_NAMES_prefix "minor-faults", \
81 VIRTIO_BALLOON_S_NAMES_prefix "free-memory", \
82 VIRTIO_BALLOON_S_NAMES_prefix "total-memory", \
83 VIRTIO_BALLOON_S_NAMES_prefix "available-memory", \
84 VIRTIO_BALLOON_S_NAMES_prefix "disk-caches", \
85 VIRTIO_BALLOON_S_NAMES_prefix "hugetlb-allocations", \
86 VIRTIO_BALLOON_S_NAMES_prefix "hugetlb-failures" \
87 }
88
89 #define VIRTIO_BALLOON_S_NAMES VIRTIO_BALLOON_S_NAMES_WITH_PREFIX("")
90
91 /*
92 * Memory statistics structure.
93 * Driver fills an array of these structures and passes to device.
94 *
95 * NOTE: fields are laid out in a way that would make compiler add padding
96 * between and after fields, so we have to use compiler-specific attributes to
97 * pack it, to disable this padding. This also often causes compiler to
98 * generate suboptimal code.
99 *
100 * We maintain this statistics structure format for backwards compatibility,
101 * but don't follow this example.
102 *
103 * If implementing a similar structure, do something like the below instead:
104 * struct virtio_balloon_stat {
105 * __virtio16 tag;
106 * __u8 reserved[6];
107 * __virtio64 val;
108 * };
109 *
110 * In other words, add explicit reserved fields to align field and
111 * structure boundaries at field size, avoiding compiler padding
112 * without the packed attribute.
113 */
114 struct virtio_balloon_stat {
115 __virtio16 tag;
116 __virtio64 val;
117 } __attribute__((packed));
118
119 #endif /* _LINUX_VIRTIO_BALLOON_H */
120
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