On Fri, Mar 03, 2017 at 01:40:29PM +0800, Wei Wang wrote:
> From: Liang Li <liang.z.li@xxxxxxxxx>
>
> Define the flags and head struct for a new host request virtual
> queue. Guest can get requests from host and then responds to
> them on this new virtual queue.
> Host can make use of this virtqueue to request the guest to do
> some operations, e.g. drop page cache, synchronize file system,
> etc. The hypervisor can get some of guest's runtime information
> through this virtual queue too, e.g. the guest's unused page
> information, which can be used for live migration optimization.
>
> Signed-off-by: Liang Li <liang.z.li@xxxxxxxxx>
> Signed-off-by: Wei Wang <wei.w.wang@xxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
> Cc: Amit Shah <amit.shah@xxxxxxxxxx>
> Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> Cc: David Hildenbrand <david@xxxxxxxxxx>
> Cc: Liang Li <liliang324@xxxxxxxxx>
> Cc: Wei Wang <wei.w.wang@xxxxxxxxx>
I prefer this squashed into next patch makes review easier.
> ---
> include/uapi/linux/virtio_balloon.h | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
> index ed627b2..630b0ef 100644
> --- a/include/uapi/linux/virtio_balloon.h
> +++ b/include/uapi/linux/virtio_balloon.h
> @@ -35,6 +35,7 @@
> #define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue */
> #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */
> #define VIRTIO_BALLOON_F_CHUNK_TRANSFER 3 /* Transfer pages in chunks */
> +#define VIRTIO_BALLOON_F_HOST_REQ_VQ 4 /* Host request virtqueue */
>
> /* Size of a PFN in the balloon interface. */
> #define VIRTIO_BALLOON_PFN_SHIFT 12
> @@ -94,4 +95,25 @@ struct virtio_balloon_resp_hdr {
> __le32 data_len; /* Payload len in bytes */
> };
>
> +enum virtio_balloon_req_id {
> + /* Get unused page information */
> + BALLOON_GET_UNUSED_PAGES,
> +};
> +
> +enum virtio_balloon_flag {
> + /* Have more data for a request */
> + BALLOON_FLAG_CONT,
> + /* No more data for a request */
> + BALLOON_FLAG_DONE,
> +};
> +
> +struct virtio_balloon_req_hdr {
> + /* Used to distinguish different requests */
> + __le16 cmd;
> + /* Reserved */
> + __le16 reserved[3];
> + /* Request parameter */
> + __le64 param;
> +};
> +
> #endif /* _LINUX_VIRTIO_BALLOON_H */
> --
> 2.7.4
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