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| author | Xiong Zhang <xiong.y.zhang@intel.corp-partner.google.com> | 2020-02-03 10:03:17 +0800 |
|---|---|---|
| committer | Commit Bot <commit-bot@chromium.org> | 2020-02-07 15:27:25 +0000 |
| commit | 5c51e052820f6f6a2e65d1bd02ff8eee6a3241a2 (patch) | |
| tree | 5853693de4d80712b63c7ca5fb1f19bf11327de8 | |
| parent | bc7728f69b804f6cee6769aa9428e83a8c647bf9 (diff) | |
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Virtio: Add fence(Acquire) after avail_index read
Driver use virtio_wmb() before avail_index updating, here fence() is compared with it, this guarantee that the descriptor_index is read after avail_index. BUG=none TEST=run fio_read and fio_write in guest Change-Id: I6a5e1bc7c915effd433b05aca246302c5a3e313c Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.corp-partner.google.com> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2035079 Reviewed-by: Dylan Reid <dgreid@chromium.org> Tested-by: kokoro <noreply+kokoro@google.com>
| -rw-r--r-- | devices/src/virtio/queue.rs | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/devices/src/virtio/queue.rs b/devices/src/virtio/queue.rs index 153449a..21cf63e 100644 --- a/devices/src/virtio/queue.rs +++ b/devices/src/virtio/queue.rs @@ -317,6 +317,8 @@ impl Queue { let queue_size = self.actual_size(); let avail_index_addr = mem.checked_offset(self.avail_ring, 2).unwrap(); let avail_index: u16 = mem.read_obj_from_addr(avail_index_addr).unwrap(); + // make sure desc_index read doesn't bypass avail_index read + fence(Ordering::Acquire); let avail_len = Wrapping(avail_index) - self.next_avail; if avail_len.0 > queue_size || self.next_avail == Wrapping(avail_index) { |