Commit 2e991629 authored by Wei Wang's avatar Wei Wang Committed by Michael S. Tsirkin
Browse files

virtio-balloon: VIRTIO_BALLOON_F_PAGE_POISON 



The VIRTIO_BALLOON_F_PAGE_POISON feature bit is used to indicate if the
guest is using page poisoning. Guest writes to the poison_val config
field to tell host about the page poisoning value that is in use.

Suggested-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarWei Wang <wei.w.wang@intel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent d95f58f4

drivers/virtio/virtio_balloon.c

+10 −0
Original line number Diff line number Diff line
@@ -825,6 +825,7 @@ static int virtio_balloon_register_shrinker(struct virtio_balloon *vb) 
static int virtballoon_probe(struct virtio_device *vdev)

{

	struct virtio_balloon *vb;

	__u32 poison_val;

	int err;



	if (!vdev->config->get) {
@@ -892,6 +893,11 @@ static int virtballoon_probe(struct virtio_device *vdev) 
		vb->num_free_page_blocks = 0;

		spin_lock_init(&vb->free_page_list_lock);

		INIT_LIST_HEAD(&vb->free_page_list);

		if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) {

			memset(&poison_val, PAGE_POISON, sizeof(poison_val));

			virtio_cwrite(vb->vdev, struct virtio_balloon_config,

				      poison_val, &poison_val);

		}

	}

	/*

	 * We continue to use VIRTIO_BALLOON_F_DEFLATE_ON_OOM to decide if a
@@ -992,6 +998,9 @@ static int virtballoon_restore(struct virtio_device *vdev) 


static int virtballoon_validate(struct virtio_device *vdev)

{

	if (!page_poisoning_enabled())

		__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_PAGE_POISON);



	__virtio_clear_bit(vdev, VIRTIO_F_IOMMU_PLATFORM);

	return 0;

}
@@ -1001,6 +1010,7 @@ static unsigned int features[] = { 
	VIRTIO_BALLOON_F_STATS_VQ,

	VIRTIO_BALLOON_F_DEFLATE_ON_OOM,

	VIRTIO_BALLOON_F_FREE_PAGE_HINT,

	VIRTIO_BALLOON_F_PAGE_POISON,

};



static struct virtio_driver virtio_balloon_driver = {

include/uapi/linux/virtio_balloon.h

+3 −0
Original line number Diff line number Diff line
@@ -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_FREE_PAGE_HINT	3 /* VQ to report free pages */

#define VIRTIO_BALLOON_F_PAGE_POISON	4 /* Guest is using page poisoning */



/* Size of a PFN in the balloon interface. */

#define VIRTIO_BALLOON_PFN_SHIFT 12
@@ -48,6 +49,8 @@ struct virtio_balloon_config { 
	__u32 actual;

	/* Free page report command id, readonly by guest */

	__u32 free_page_report_cmd_id;

	/* Stores PAGE_POISON if page poisoning is in use */

	__u32 poison_val;

};



#define VIRTIO_BALLOON_S_SWAP_IN  0   /* Amount of memory swapped in */

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