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_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 */
114struct virtio_balloon_stat {
115	__virtio16 tag;
116	__virtio64 val;
117} __attribute__((packed));
118
119#endif /* _LINUX_VIRTIO_BALLOON_H */
120