@@ -58,6 +58,7 @@ config VIRTIO_BALLOON
tristate "Virtio balloon driver"
depends on VIRTIO
select MEMORY_BALLOON
+ select PAGE_REPORTING
---help---
This driver supports increasing and decreasing the amount
of memory within a KVM guest.
@@ -19,6 +19,7 @@
#include <linux/mount.h>
#include <linux/magic.h>
#include <linux/pseudo_fs.h>
+#include <linux/page_reporting.h>
/*
* Balloon device works in 4K page units. So each page is pointed to by
@@ -37,6 +38,9 @@
#define VIRTIO_BALLOON_FREE_PAGE_SIZE \
(1 << (VIRTIO_BALLOON_FREE_PAGE_ORDER + PAGE_SHIFT))
+/* limit on the number of pages that can be on the reporting vq */
+#define VIRTIO_BALLOON_VRING_HINTS_MAX 16
+
#ifdef CONFIG_BALLOON_COMPACTION
static struct vfsmount *balloon_mnt;
#endif
@@ -46,6 +50,7 @@ enum virtio_balloon_vq {
VIRTIO_BALLOON_VQ_DEFLATE,
VIRTIO_BALLOON_VQ_STATS,
VIRTIO_BALLOON_VQ_FREE_PAGE,
+ VIRTIO_BALLOON_VQ_REPORTING,
VIRTIO_BALLOON_VQ_MAX
};
@@ -113,6 +118,10 @@ struct virtio_balloon {
/* To register a shrinker to shrink memory upon memory pressure */
struct shrinker shrinker;
+
+ /* Unused page reporting device */
+ struct virtqueue *reporting_vq;
+ struct page_reporting_dev_info ph_dev_info;
};
static struct virtio_device_id id_table[] = {
@@ -152,6 +161,32 @@ static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq)
}
+void virtballoon_unused_page_report(struct page_reporting_dev_info *ph_dev_info,
+ unsigned int nents)
+{
+ struct virtio_balloon *vb =
+ container_of(ph_dev_info, struct virtio_balloon, ph_dev_info);
+ struct virtqueue *vq = vb->reporting_vq;
+ unsigned int unused, err;
+
+ /* We should always be able to add these buffers to an empty queue. */
+ err = virtqueue_add_inbuf(vq, ph_dev_info->sg, nents, vb,
+ GFP_NOWAIT | __GFP_NOWARN);
+
+ /*
+ * In the extremely unlikely case that something has changed and we
+ * are able to trigger an error we will simply display a warning
+ * and exit without actually processing the pages.
+ */
+ if (WARN_ON(err))
+ return;
+
+ virtqueue_kick(vq);
+
+ /* When host has read buffer, this completes via balloon_ack */
+ wait_event(vb->acked, virtqueue_get_buf(vq, &unused));
+}
+
static void set_page_pfns(struct virtio_balloon *vb,
__virtio32 pfns[], struct page *page)
{
@@ -476,6 +511,7 @@ static int init_vqs(struct virtio_balloon *vb)
names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate";
names[VIRTIO_BALLOON_VQ_STATS] = NULL;
names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
+ names[VIRTIO_BALLOON_VQ_REPORTING] = NULL;
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
names[VIRTIO_BALLOON_VQ_STATS] = "stats";
@@ -487,11 +523,19 @@ static int init_vqs(struct virtio_balloon *vb)
callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
}
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) {
+ names[VIRTIO_BALLOON_VQ_REPORTING] = "reporting_vq";
+ callbacks[VIRTIO_BALLOON_VQ_REPORTING] = balloon_ack;
+ }
+
err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX,
vqs, callbacks, names, NULL, NULL);
if (err)
return err;
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING))
+ vb->reporting_vq = vqs[VIRTIO_BALLOON_VQ_REPORTING];
+
vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE];
vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE];
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
@@ -931,12 +975,30 @@ static int virtballoon_probe(struct virtio_device *vdev)
if (err)
goto out_del_balloon_wq;
}
+
+ vb->ph_dev_info.report = virtballoon_unused_page_report;
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) {
+ unsigned int capacity;
+
+ capacity = min_t(unsigned int,
+ virtqueue_get_vring_size(vb->reporting_vq) - 1,
+ VIRTIO_BALLOON_VRING_HINTS_MAX);
+ vb->ph_dev_info.capacity = capacity;
+
+ err = page_reporting_startup(&vb->ph_dev_info);
+ if (err)
+ goto out_unregister_shrinker;
+ }
+
virtio_device_ready(vdev);
if (towards_target(vb))
virtballoon_changed(vdev);
return 0;
+out_unregister_shrinker:
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
+ virtio_balloon_unregister_shrinker(vb);
out_del_balloon_wq:
if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
destroy_workqueue(vb->balloon_wq);
@@ -965,6 +1027,8 @@ static void virtballoon_remove(struct virtio_device *vdev)
{
struct virtio_balloon *vb = vdev->priv;
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING))
+ page_reporting_shutdown(&vb->ph_dev_info);
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
virtio_balloon_unregister_shrinker(vb);
spin_lock_irq(&vb->stop_update_lock);
@@ -1034,6 +1098,7 @@ static int virtballoon_validate(struct virtio_device *vdev)
VIRTIO_BALLOON_F_DEFLATE_ON_OOM,
VIRTIO_BALLOON_F_FREE_PAGE_HINT,
VIRTIO_BALLOON_F_PAGE_POISON,
+ VIRTIO_BALLOON_F_REPORTING,
};
static struct virtio_driver virtio_balloon_driver = {
@@ -36,6 +36,7 @@
#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 */
+#define VIRTIO_BALLOON_F_REPORTING 5 /* Page reporting virtqueue */
/* Size of a PFN in the balloon interface. */
#define VIRTIO_BALLOON_PFN_SHIFT 12