If the guest is using a non-zero poisoning, we don't skip the transfer
of guest free pages.
Todo: As a next step optimization, we can try
1) skip the transfer of guest poisoned free pages;
2) send the poison value to destination; and
3) seek a way to poison the guest free pages before the guest starts to
run on the destination.
Signed-off-by: Wei Wang <wei.w.w...@intel.com>
CC: Michael S. Tsirkin <m...@redhat.com>
---
hw/virtio/virtio-balloon.c | 3 ++-
include/hw/virtio/virtio-balloon.h | 1 +
include/standard-headers/linux/virtio_balloon.h | 2 ++
3 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index dcc8cb3..0cdc755 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -403,7 +403,7 @@ static void virtio_balloon_handle_free_pages(VirtIODevice
*vdev, VirtQueue *vq)
ram_addr_t offset;
if (atomic_read(&dev->free_page_report_status) ==
- FREE_PAGE_REPORT_S_IN_PROGRESS) {
+ FREE_PAGE_REPORT_S_IN_PROGRESS && !dev->poison_val) {
block = qemu_ram_block_from_host(elem->in_sg[0].iov_base,
false, &offset);
size = elem->in_sg[0].iov_len;
@@ -530,6 +530,7 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
&error_abort);
}
+ dev->poison_val = le32_to_cpu(config.poison_val);
trace_virtio_balloon_set_config(dev->actual, oldactual);
}
diff --git a/include/hw/virtio/virtio-balloon.h
b/include/hw/virtio/virtio-balloon.h
index 268f7d6..0bb80cd 100644
--- a/include/hw/virtio/virtio-balloon.h
+++ b/include/hw/virtio/virtio-balloon.h
@@ -43,6 +43,7 @@ typedef struct VirtIOBalloon {
uint32_t num_pages;
uint32_t actual;
uint32_t free_page_report_cmd_id;
+ uint32_t poison_val;
uint64_t stats[VIRTIO_BALLOON_S_NR];
VirtQueueElement *stats_vq_elem;
size_t stats_vq_offset;
diff --git a/include/standard-headers/linux/virtio_balloon.h
b/include/standard-headers/linux/virtio_balloon.h
index 596df5d..f6f4ff3 100644
--- a/include/standard-headers/linux/virtio_balloon.h
+++ b/include/standard-headers/linux/virtio_balloon.h
@@ -47,6 +47,8 @@ struct virtio_balloon_config {
uint32_t actual;
/* The free_page report command id, readonly by guest */
uint32_t free_page_report_cmd_id;
+ /* Stores PAGE_POISON if page poisoning with sanity check is in use */
+ uint32_t poison_val;
};
#define VIRTIO_BALLOON_S_SWAP_IN 0 /* Amount of memory swapped in */
--
1.8.3.1
