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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
46struct 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_OOM_KILL 10 /* OOM killer invocations */
75#define VIRTIO_BALLOON_S_ALLOC_STALL 11 /* Stall count of memory allocatoin */
76#define VIRTIO_BALLOON_S_ASYNC_SCAN 12 /* Amount of memory scanned asynchronously */
77#define VIRTIO_BALLOON_S_DIRECT_SCAN 13 /* Amount of memory scanned directly */
78#define VIRTIO_BALLOON_S_ASYNC_RECLAIM 14 /* Amount of memory reclaimed asynchronously */
79#define VIRTIO_BALLOON_S_DIRECT_RECLAIM 15 /* Amount of memory reclaimed directly */
80#define VIRTIO_BALLOON_S_NR 16
81
82#define VIRTIO_BALLOON_S_NAMES_WITH_PREFIX(VIRTIO_BALLOON_S_NAMES_prefix) { \
83 VIRTIO_BALLOON_S_NAMES_prefix "swap-in", \
84 VIRTIO_BALLOON_S_NAMES_prefix "swap-out", \
85 VIRTIO_BALLOON_S_NAMES_prefix "major-faults", \
86 VIRTIO_BALLOON_S_NAMES_prefix "minor-faults", \
87 VIRTIO_BALLOON_S_NAMES_prefix "free-memory", \
88 VIRTIO_BALLOON_S_NAMES_prefix "total-memory", \
89 VIRTIO_BALLOON_S_NAMES_prefix "available-memory", \
90 VIRTIO_BALLOON_S_NAMES_prefix "disk-caches", \
91 VIRTIO_BALLOON_S_NAMES_prefix "hugetlb-allocations", \
92 VIRTIO_BALLOON_S_NAMES_prefix "hugetlb-failures", \
93 VIRTIO_BALLOON_S_NAMES_prefix "oom-kills", \
94 VIRTIO_BALLOON_S_NAMES_prefix "alloc-stalls", \
95 VIRTIO_BALLOON_S_NAMES_prefix "async-scans", \
96 VIRTIO_BALLOON_S_NAMES_prefix "direct-scans", \
97 VIRTIO_BALLOON_S_NAMES_prefix "async-reclaims", \
98 VIRTIO_BALLOON_S_NAMES_prefix "direct-reclaims" \
99}
100
101#define VIRTIO_BALLOON_S_NAMES VIRTIO_BALLOON_S_NAMES_WITH_PREFIX("")
102
103/*
104 * Memory statistics structure.
105 * Driver fills an array of these structures and passes to device.
106 *
107 * NOTE: fields are laid out in a way that would make compiler add padding
108 * between and after fields, so we have to use compiler-specific attributes to
109 * pack it, to disable this padding. This also often causes compiler to
110 * generate suboptimal code.
111 *
112 * We maintain this statistics structure format for backwards compatibility,
113 * but don't follow this example.
114 *
115 * If implementing a similar structure, do something like the below instead:
116 * struct virtio_balloon_stat {
117 * __virtio16 tag;
118 * __u8 reserved[6];
119 * __virtio64 val;
120 * };
121 *
122 * In other words, add explicit reserved fields to align field and
123 * structure boundaries at field size, avoiding compiler padding
124 * without the packed attribute.
125 */
126struct virtio_balloon_stat {
127 __virtio16 tag;
128 __virtio64 val;
129} __attribute__((packed));
130
131#endif /* _LINUX_VIRTIO_BALLOON_H */