Add a new vq, cmdq, to handle requests between the device and driver.
This patch implements two commands sent from the device and handled in
the driver.
1) VIRTIO_BALLOON_CMDQ_REPORT_STATS: this command is used to report
the guest memory statistics to the host. The stats_vq mechanism is not
used when the cmdq mechanism is enabled.
2) VIRTIO_BALLOON_CMDQ_REPORT_UNUSED_PAGES: this command is used to
report the guest unused pages to the host.
Since now we have a vq to handle multiple commands, we need to keep only
one vq operation at a time. Here, we change the existing START_USE()
and END_USE() to lock on each vq operation.
Signed-off-by: Wei Wang <address@hidden>
Signed-off-by: Liang Li <address@hidden>
---
drivers/virtio/virtio_balloon.c | 245 ++++++++++++++++++++++++++++++++++--
drivers/virtio/virtio_ring.c | 25 +++-
include/linux/virtio.h | 2 +
include/uapi/linux/virtio_balloon.h | 10 ++
4 files changed, 265 insertions(+), 17 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index aa4e7ec..ae91fbf 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -54,11 +54,12 @@ static struct vfsmount *balloon_mnt;
struct virtio_balloon {
struct virtio_device *vdev;
- struct virtqueue *inflate_vq, *deflate_vq, *stats_vq;
+ struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *cmd_vq;
/* The balloon servicing is delegated to a freezable workqueue. */
struct work_struct update_balloon_stats_work;
struct work_struct update_balloon_size_work;
+ struct work_struct cmdq_handle_work;
/* Prevent updating balloon when it is being canceled. */
spinlock_t stop_update_lock;
@@ -90,6 +91,12 @@ struct virtio_balloon {
/* Memory statistics */
struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR];
+ /* Cmdq msg buffer for memory statistics */
+ struct virtio_balloon_cmdq_hdr cmdq_stats_hdr;
+
+ /* Cmdq msg buffer for reporting ununsed pages */
+ struct virtio_balloon_cmdq_hdr cmdq_unused_page_hdr;
+
/* To register callback in oom notifier call chain */
struct notifier_block nb;
};
@@ -485,25 +492,214 @@ static void update_balloon_size_func(struct work_struct
*work)
queue_work(system_freezable_wq, work);
}
+static unsigned int cmdq_hdr_add(struct virtqueue *vq,
+ struct virtio_balloon_cmdq_hdr *hdr,
+ bool in)
+{
+ unsigned int id = VIRTQUEUE_DESC_ID_INIT;
+ uint64_t hdr_pa = (uint64_t)virt_to_phys((void *)hdr);
+
+ virtqueue_add_chain_desc(vq, hdr_pa, sizeof(*hdr), &id, &id, in);
+
+ /* Deliver the hdr for the host to send commands. */
+ if (in) {
+ hdr->flags = 0;
+ virtqueue_add_chain(vq, id, 0, NULL, hdr, NULL);
+ virtqueue_kick(vq);
+ }
+
+ return id;
+}
+
+static void cmdq_add_chain_desc(struct virtio_balloon *vb,
+ struct virtio_balloon_cmdq_hdr *hdr,
+ uint64_t addr,
+ uint32_t len,
+ unsigned int *head_id,
+ unsigned int *prev_id)
+{
+retry:
+ if (*head_id == VIRTQUEUE_DESC_ID_INIT) {
+ *head_id = cmdq_hdr_add(vb->cmd_vq, hdr, 0);
+ *prev_id = *head_id;
+ }
+
+ virtqueue_add_chain_desc(vb->cmd_vq, addr, len, head_id, prev_id, 0);
+ if (*head_id == *prev_id) {