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Merge tag 'rpmsg-v4.15' of git://github.com/andersson/remoteproc
[mirror_ubuntu-bionic-kernel.git] / include / uapi / linux / virtio_balloon.h
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1#ifndef _LINUX_VIRTIO_BALLOON_H
2#define _LINUX_VIRTIO_BALLOON_H
674bfc23 3/* This header is BSD licensed so anyone can use the definitions to implement
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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. */
df81b29c 28#include <linux/types.h>
8a7b19d8 29#include <linux/virtio_types.h>
e95646c3 30#include <linux/virtio_ids.h>
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31#include <linux/virtio_config.h>
32
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33/* The feature bitmap for virtio balloon */
34#define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */
9564e138 35#define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue */
5a10b7db 36#define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */
6b35e407 37
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38/* Size of a PFN in the balloon interface. */
39#define VIRTIO_BALLOON_PFN_SHIFT 12
40
25e65e4e 41struct virtio_balloon_config {
6b35e407 42 /* Number of pages host wants Guest to give up. */
df81b29c 43 __u32 num_pages;
6b35e407 44 /* Number of pages we've actually got in balloon. */
df81b29c 45 __u32 actual;
6b35e407 46};
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47
48#define VIRTIO_BALLOON_S_SWAP_IN 0 /* Amount of memory swapped in */
49#define VIRTIO_BALLOON_S_SWAP_OUT 1 /* Amount of memory swapped out */
50#define VIRTIO_BALLOON_S_MAJFLT 2 /* Number of major faults */
51#define VIRTIO_BALLOON_S_MINFLT 3 /* Number of minor faults */
52#define VIRTIO_BALLOON_S_MEMFREE 4 /* Total amount of free memory */
53#define VIRTIO_BALLOON_S_MEMTOT 5 /* Total amount of memory */
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54#define VIRTIO_BALLOON_S_AVAIL 6 /* Available memory as in /proc */
55#define VIRTIO_BALLOON_S_NR 7
9564e138 56
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57/*
58 * Memory statistics structure.
59 * Driver fills an array of these structures and passes to device.
60 *
61 * NOTE: fields are laid out in a way that would make compiler add padding
62 * between and after fields, so we have to use compiler-specific attributes to
63 * pack it, to disable this padding. This also often causes compiler to
64 * generate suboptimal code.
65 *
66 * We maintain this statistics structure format for backwards compatibility,
67 * but don't follow this example.
68 *
69 * If implementing a similar structure, do something like the below instead:
70 * struct virtio_balloon_stat {
71 * __virtio16 tag;
72 * __u8 reserved[6];
73 * __virtio64 val;
74 * };
75 *
76 * In other words, add explicit reserved fields to align field and
77 * structure boundaries at field size, avoiding compiler padding
78 * without the packed attribute.
79 */
9564e138 80struct virtio_balloon_stat {
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81 __virtio16 tag;
82 __virtio64 val;
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83} __attribute__((packed));
84
6b35e407 85#endif /* _LINUX_VIRTIO_BALLOON_H */