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[PATCH 62/77] virtio-balloon: always indicate S_DONE when migration fail
From: |
Michael Roth |
Subject: |
[PATCH 62/77] virtio-balloon: always indicate S_DONE when migration fails |
Date: |
Thu, 3 Sep 2020 15:59:20 -0500 |
From: David Hildenbrand <david@redhat.com>
If something goes wrong during precopy, before stopping the VM, we will
never send a S_DONE indication to the VM, resulting in the hinted pages
not getting released to be used by the guest OS (e.g., Linux).
Easy to reproduce:
1. Start migration (e.g., HMP "migrate -d 'exec:gzip -c > STATEFILE.gz'")
2. Cancel migration (e.g., HMP "migrate_cancel")
3. Oberve in the guest (e.g., cat /proc/meminfo) that there is basically
no free memory left.
While at it, add similar locking to virtio_balloon_free_page_done() as
done in virtio_balloon_free_page_stop. Locking is still weird, but that
has to be sorted out separately.
There is nothing to do in the PRECOPY_NOTIFY_COMPLETE case. Add some
comments regarding S_DONE handling.
Fixes: c13c4153f76d ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT")
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Wei Wang <wei.w.wang@intel.com>
Cc: Alexander Duyck <alexander.duyck@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20200629080615.26022-1-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit dd8eeb9671fc881e613008bd20035b85fe45383d)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
hw/virtio/virtio-balloon.c | 26 ++++++++++++++++++++------
1 file changed, 20 insertions(+), 6 deletions(-)
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index d6e31de1d9..6c75db123e 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -572,8 +572,13 @@ static void virtio_balloon_free_page_done(VirtIOBalloon *s)
{
VirtIODevice *vdev = VIRTIO_DEVICE(s);
- s->free_page_report_status = FREE_PAGE_REPORT_S_DONE;
- virtio_notify_config(vdev);
+ if (s->free_page_report_status != FREE_PAGE_REPORT_S_DONE) {
+ /* See virtio_balloon_free_page_stop() */
+ qemu_mutex_lock(&s->free_page_lock);
+ s->free_page_report_status = FREE_PAGE_REPORT_S_DONE;
+ qemu_mutex_unlock(&s->free_page_lock);
+ virtio_notify_config(vdev);
+ }
}
static int
@@ -597,17 +602,26 @@ virtio_balloon_free_page_report_notify(NotifierWithReturn
*n, void *data)
case PRECOPY_NOTIFY_SETUP:
precopy_enable_free_page_optimization();
break;
- case PRECOPY_NOTIFY_COMPLETE:
- case PRECOPY_NOTIFY_CLEANUP:
case PRECOPY_NOTIFY_BEFORE_BITMAP_SYNC:
virtio_balloon_free_page_stop(dev);
break;
case PRECOPY_NOTIFY_AFTER_BITMAP_SYNC:
if (vdev->vm_running) {
virtio_balloon_free_page_start(dev);
- } else {
- virtio_balloon_free_page_done(dev);
+ break;
}
+ /*
+ * Set S_DONE before migrating the vmstate, so the guest will reuse
+ * all hinted pages once running on the destination. Fall through.
+ */
+ case PRECOPY_NOTIFY_CLEANUP:
+ /*
+ * Especially, if something goes wrong during precopy or if migration
+ * is canceled, we have to properly communicate S_DONE to the VM.
+ */
+ virtio_balloon_free_page_done(dev);
+ break;
+ case PRECOPY_NOTIFY_COMPLETE:
break;
default:
virtio_error(vdev, "%s: %d reason unknown", __func__, pnd->reason);
--
2.17.1
- [PATCH 63/77] linux-headers: update against Linux 5.7-rc3, (continued)
- [PATCH 63/77] linux-headers: update against Linux 5.7-rc3, Michael Roth, 2020/09/03
- [PATCH 65/77] virtio: list legacy-capable devices, Michael Roth, 2020/09/03
- [PATCH 67/77] intel_iommu: Use correct shift for 256 bits qi descriptor, Michael Roth, 2020/09/03
- [PATCH 69/77] libvhost-user: Report descriptor index on panic, Michael Roth, 2020/09/03
- [PATCH 06/77] nbd/server: Avoid long error message assertions CVE-2020-10761, Michael Roth, 2020/09/03
- [PATCH 71/77] migration/block-dirty-bitmap: fix dirty_bitmap_mig_before_vm_start, Michael Roth, 2020/09/03
- [PATCH 64/77] virtio-balloon: Replace free page hinting references to 'report' with 'hint', Michael Roth, 2020/09/03
- [PATCH 66/77] virtio: verify that legacy support is not accidentally on, Michael Roth, 2020/09/03
- [PATCH 68/77] virtio-pci: Changed vdev to proxy for VirtIO PCI BAR callbacks., Michael Roth, 2020/09/03
- [PATCH 62/77] virtio-balloon: always indicate S_DONE when migration fails,
Michael Roth <=
- [PATCH 72/77] block: Fix bdrv_aligned_p*v() for qiov_offset != 0, Michael Roth, 2020/09/03
- [PATCH 73/77] iotests/028: Add test for cross-base-EOF reads, Michael Roth, 2020/09/03
- [PATCH 74/77] nbd: Fix large trim/zero requests, Michael Roth, 2020/09/03
- [PATCH 70/77] Update OpenBIOS images to 7f28286f built from submodule., Michael Roth, 2020/09/03
- [PATCH 75/77] virtio-net: align RSC fields with updated virtio-net header, Michael Roth, 2020/09/03
- [PATCH 76/77] hw/arm/sbsa-ref: fix typo breaking PCIe IRQs, Michael Roth, 2020/09/03
- [PATCH 77/77] usb: fix setup_len init (CVE-2020-14364), Michael Roth, 2020/09/03
- [PATCH 07/77] virtio-balloon: fix free page hinting without an iothread, Michael Roth, 2020/09/03
- [PATCH 08/77] virtio-balloon: fix free page hinting check on unrealize, Michael Roth, 2020/09/03
- Re: [PATCH 00/77] Patch Round-up for stable 5.0.1, freeze on 2020-09-10, Philippe Mathieu-Daudé, 2020/09/04