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Diffstat (limited to 'include/uapi/linux/virtio_balloon.h')
| -rw-r--r-- | include/uapi/linux/virtio_balloon.h | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h new file mode 100644 index 000000000..d7f1cbc37 --- /dev/null +++ b/include/uapi/linux/virtio_balloon.h @@ -0,0 +1,84 @@ +#ifndef _LINUX_VIRTIO_BALLOON_H +#define _LINUX_VIRTIO_BALLOON_H +/* This header is BSD licensed so anyone can use the definitions to implement + * compatible drivers/servers. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of IBM nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. */ +#include <linux/types.h> +#include <linux/virtio_types.h> +#include <linux/virtio_ids.h> +#include <linux/virtio_config.h> + +/* The feature bitmap for virtio balloon */ +#define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */ +#define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue */ +#define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */ + +/* Size of a PFN in the balloon interface. */ +#define VIRTIO_BALLOON_PFN_SHIFT 12 + +struct virtio_balloon_config { + /* Number of pages host wants Guest to give up. */ + __u32 num_pages; + /* Number of pages we've actually got in balloon. */ + __u32 actual; +}; + +#define VIRTIO_BALLOON_S_SWAP_IN 0 /* Amount of memory swapped in */ +#define VIRTIO_BALLOON_S_SWAP_OUT 1 /* Amount of memory swapped out */ +#define VIRTIO_BALLOON_S_MAJFLT 2 /* Number of major faults */ +#define VIRTIO_BALLOON_S_MINFLT 3 /* Number of minor faults */ +#define VIRTIO_BALLOON_S_MEMFREE 4 /* Total amount of free memory */ +#define VIRTIO_BALLOON_S_MEMTOT 5 /* Total amount of memory */ +#define VIRTIO_BALLOON_S_NR 6 + +/* + * Memory statistics structure. + * Driver fills an array of these structures and passes to device. + * + * NOTE: fields are laid out in a way that would make compiler add padding + * between and after fields, so we have to use compiler-specific attributes to + * pack it, to disable this padding. This also often causes compiler to + * generate suboptimal code. + * + * We maintain this statistics structure format for backwards compatibility, + * but don't follow this example. + * + * If implementing a similar structure, do something like the below instead: + * struct virtio_balloon_stat { + * __virtio16 tag; + * __u8 reserved[6]; + * __virtio64 val; + * }; + * + * In other words, add explicit reserved fields to align field and + * structure boundaries at field size, avoiding compiler padding + * without the packed attribute. + */ +struct virtio_balloon_stat { + __virtio16 tag; + __virtio64 val; +} __attribute__((packed)); + +#endif /* _LINUX_VIRTIO_BALLOON_H */ |