Patchwork [PULL,2/2] hw/virtio/virtio-mmio: Make QueueNumMax read 0 for unavailable queues

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Submitter Peter Maydell
Date Aug. 12, 2013, 11:01 a.m.
Message ID <1376305261-29561-3-git-send-email-peter.maydell@linaro.org>
Download mbox | patch
Permalink /patch/266487/
State New
Headers show

Comments

Peter Maydell - Aug. 12, 2013, 11:01 a.m.
The virtio-mmio spec says that QueueNumMax must read zero for queues
which are unavailable; implement this, rather than always returning
VIRTQUEUE_MAX_SIZE.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1374853288-9912-3-git-send-email-peter.maydell@linaro.org
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/virtio-mmio.c |    3 +++
 1 file changed, 3 insertions(+)

Patch

diff --git a/hw/virtio/virtio-mmio.c b/hw/virtio/virtio-mmio.c
index 88cf994..4bd2953 100644
--- a/hw/virtio/virtio-mmio.c
+++ b/hw/virtio/virtio-mmio.c
@@ -151,6 +151,9 @@  static uint64_t virtio_mmio_read(void *opaque, hwaddr offset, unsigned size)
         }
         return proxy->host_features;
     case VIRTIO_MMIO_QUEUENUMMAX:
+        if (!virtio_queue_get_num(vdev, vdev->queue_sel)) {
+            return 0;
+        }
         return VIRTQUEUE_MAX_SIZE;
     case VIRTIO_MMIO_QUEUEPFN:
         return virtio_queue_get_addr(vdev, vdev->queue_sel)