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| author | Ladi Prosek <lprosek@redhat.com> | 2017-03-23 08:04:18 +0100 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2017-03-28 19:41:27 +0200 |
| commit | fc8653228c8588a120f6b5dad6983b7b61ff669e (patch) | |
| tree | 93023e1808febcc42d14c19f9529e5b650fa21c1 /mm | |
| parent | virtio_pci: fix out of bound access for msix_names (diff) | |
| download | linux-fc8653228c8588a120f6b5dad6983b7b61ff669e.tar.xz linux-fc8653228c8588a120f6b5dad6983b7b61ff669e.zip | |
virtio_balloon: init 1st buffer in stats vq
When init_vqs runs, virtio_balloon.stats is either uninitialized or
contains stale values. The host updates its state with garbage data
because it has no way of knowing that this is just a marker buffer
used for signaling.
This patch updates the stats before pushing the initial buffer.
Alternative fixes:
* Push an empty buffer in init_vqs. Not easily done with the current
virtio implementation and violates the spec "Driver MUST supply the
same subset of statistics in all buffers submitted to the statsq".
* Push a buffer with invalid tags in init_vqs. Violates the same
spec clause, plus "invalid tag" is not really defined.
Note: the spec says:
When using the legacy interface, the device SHOULD ignore all values in
the first buffer in the statsq supplied by the driver after device
initialization. Note: Historically, drivers supplied an uninitialized
buffer in the first buffer.
Unfortunately QEMU does not seem to implement the recommendation
even for the legacy interface.
Cc: stable@vger.kernel.org
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'mm')
0 files changed, 0 insertions, 0 deletions