[RFC,1/4] virtio: Add support for guest setting of queue size

Submitted by Peter Maydell on Nov. 14, 2011, 2:55 p.m.


Message ID 1321282528-19070-2-git-send-email-peter.maydell@linaro.org
State New
Headers show

Commit Message

Peter Maydell Nov. 14, 2011, 2:55 p.m.
The MMIO virtio transport spec allows the guest to tell the host how
large the queue size is. Add virtio_queue_set_num() function which
implements this in the QEMU common virtio support code.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
 hw/virtio.c |    6 ++++++
 hw/virtio.h |    1 +
 2 files changed, 7 insertions(+), 0 deletions(-)

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diff --git a/hw/virtio.c b/hw/virtio.c
index 7011b5b..5bd43a1 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -619,6 +619,12 @@  target_phys_addr_t virtio_queue_get_addr(VirtIODevice *vdev, int n)
     return vdev->vq[n].pa;
+void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
+    vdev->vq[n].vring.num = num;
+    virtqueue_init(&vdev->vq[n]);
 int virtio_queue_get_num(VirtIODevice *vdev, int n)
     return vdev->vq[n].vring.num;
diff --git a/hw/virtio.h b/hw/virtio.h
index 2d18209..352aba6 100644
--- a/hw/virtio.h
+++ b/hw/virtio.h
@@ -178,6 +178,7 @@  void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data);
 void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data);
 void virtio_queue_set_addr(VirtIODevice *vdev, int n, target_phys_addr_t addr);
 target_phys_addr_t virtio_queue_get_addr(VirtIODevice *vdev, int n);
+void virtio_queue_set_num(VirtIODevice *vdev, int n, int num);
 int virtio_queue_get_num(VirtIODevice *vdev, int n);
 void virtio_queue_notify(VirtIODevice *vdev, int n);
 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n);