[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 1/2] hw/virtio/virtio: Don't allow guests to add
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] hw/virtio/virtio: Don't allow guests to add/remove queues |
Date: |
Fri, 26 Jul 2013 01:33:17 +0300 |
On Thu, Jul 25, 2013 at 02:37:42PM +0100, Peter Maydell wrote:
> A queue size of 0 is used to indicate a nonexistent queue, so
> don't allow the guest to flip a queue between zero-size and
> non-zero-size. Don't permit setting of negative queue sizes
> either.
>
> Signed-off-by: Peter Maydell <address@hidden>
> ---
> hw/virtio/virtio.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 09f62c6..d5b0502 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -673,10 +673,14 @@ hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
>
> void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
> {
> - if (num <= VIRTQUEUE_MAX_SIZE) {
> - vdev->vq[n].vring.num = num;
> - virtqueue_init(&vdev->vq[n]);
> + if ((num == 0 && vdev->vq[n].vring.num != 0) ||
> + (num != 0 && vdev->vq[n].vring.num == 0) ||
Cleaner (imho)
!num != !vdev->vq[n].vring.num
> + (num > VIRTQUEUE_MAX_SIZE) ||
Pls don't put () around simple math.
It has natural precedence wrt <> so it just makes it
look like lisp.
> + (num < 0)) {
How does it ever get negative?
assert (num >= 0) instead?
> + return;
> }
> + vdev->vq[n].vring.num = num;
> + virtqueue_init(&vdev->vq[n]);
> }
>
> int virtio_queue_get_num(VirtIODevice *vdev, int n)
> --
> 1.7.9.5
[Qemu-devel] [PATCH 2/2] hw/virtio/virtio-mmio: Make QueueNumMax read 0 for unavailable queues, Peter Maydell, 2013/07/25