diff mbox

[RESEND,v3,kernel,6/7] virtio-balloon: define feature bit and head for misc virt queue

Message ID 1477031080-12616-7-git-send-email-liang.z.li@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Liang Li Oct. 21, 2016, 6:24 a.m. UTC
Define a new feature bit which supports a new virtual queue. This
new virtual qeuque is for information exchange between hypervisor
and guest. The VMM hypervisor can make use of this virtual queue
to request the guest do some operations, e.g. drop page cache,
synchronize file system, etc. And the VMM hypervisor can get some
of guest's runtime information through this virtual queue, e.g. the
guest's unused page information, which can be used for live migration
optimization.

Signed-off-by: Liang Li <liang.z.li@intel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Amit Shah <amit.shah@redhat.com>
---
 include/uapi/linux/virtio_balloon.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

Comments

Michael S. Tsirkin Oct. 27, 2016, 6:29 p.m. UTC | #1
On Fri, Oct 21, 2016 at 02:24:39PM +0800, Liang Li wrote:
> Define a new feature bit which supports a new virtual queue. This
> new virtual qeuque is for information exchange between hypervisor
> and guest. The VMM hypervisor can make use of this virtual queue
> to request the guest do some operations, e.g. drop page cache,
> synchronize file system, etc.

Can we call this something more informative pls?
host request vq?

> And the VMM hypervisor can get some
> of guest's runtime information through this virtual queue, e.g. the
> guest's unused page information, which can be used for live migration
> optimization.

I guess the idea is that guest gets requests from host and
then responds to them on this vq. Pls document.

> 
> Signed-off-by: Liang Li <liang.z.li@intel.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
> Cc: Amit Shah <amit.shah@redhat.com>
> ---
>  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 d3b182a..3a9d633 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_PAGE_BITMAP	3 /* Send page info with bitmap */
> +#define VIRTIO_BALLOON_F_MISC_VQ	4 /* Misc info virtqueue */
>  
>  /* Size of a PFN in the balloon interface. */
>  #define VIRTIO_BALLOON_PFN_SHIFT 12
> @@ -101,4 +102,25 @@ struct balloon_bmap_hdr {
>  	__virtio64 bmap_len;
>  };
>  
> +enum balloon_req_id {
> +	/* Get unused pages information */

unused page information


> +	BALLOON_GET_UNUSED_PAGES,
> +};
> +
> +enum balloon_flag {
> +	/* Have more data for a request */
> +	BALLOON_FLAG_CONT,
> +	/* No more data for a request */
> +	BALLOON_FLAG_DONE,
> +};

is this a bit number or a value? Pls name consistently.

> +
> +struct balloon_req_hdr {
> +	/* Used to distinguish different request */

requests

> +	__virtio16 cmd;
> +	/* Reserved */
> +	__virtio16 reserved[3];
> +	/* Request parameter */
> +	__virtio64 param;
> +};
> +
>  #endif /* _LINUX_VIRTIO_BALLOON_H */


Prefix structs with virtio_ as well pls.
Also, wouldn't it simplify code if we use __le for new structs?

> -- 
> 1.8.3.1
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diff mbox

Patch

diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
index d3b182a..3a9d633 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_PAGE_BITMAP	3 /* Send page info with bitmap */
+#define VIRTIO_BALLOON_F_MISC_VQ	4 /* Misc info virtqueue */
 
 /* Size of a PFN in the balloon interface. */
 #define VIRTIO_BALLOON_PFN_SHIFT 12
@@ -101,4 +102,25 @@  struct balloon_bmap_hdr {
 	__virtio64 bmap_len;
 };
 
+enum balloon_req_id {
+	/* Get unused pages information */
+	BALLOON_GET_UNUSED_PAGES,
+};
+
+enum balloon_flag {
+	/* Have more data for a request */
+	BALLOON_FLAG_CONT,
+	/* No more data for a request */
+	BALLOON_FLAG_DONE,
+};
+
+struct balloon_req_hdr {
+	/* Used to distinguish different request */
+	__virtio16 cmd;
+	/* Reserved */
+	__virtio16 reserved[3];
+	/* Request parameter */
+	__virtio64 param;
+};
+
 #endif /* _LINUX_VIRTIO_BALLOON_H */