On Wed, Jun 27, 2018 at 04:55:20PM +0530, Pankaj Gupta wrote:
> virtio-rng device causing old guest kernels(2.6.32) to hang on latest qemu.
> The driver attempts to read from the virtio-rng device too early in it's
> initialization. Qemu detects guest is not ready and returns, resulting in
> hang.
Presumably this all worked previously at some point, so do you know what
change in QEMU has caused a regression in this regard.
>
> Fix is to handle pending request when guest is running and driver status is
> set to 'VIRTIO_CONFIG_S_DRIVER_OK'.
>
> Reported-by: Sergio lopez <slope...@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
> Signed-off-by: Pankaj Gupta <pagu...@redhat.com>
> ---
> v1->v2: Update new status value early only for virtio-rng (Stefan)
>
> hw/virtio/virtio-rng.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/hw/virtio/virtio-rng.c b/hw/virtio/virtio-rng.c
> index 289bbcac03..855f1b41d1 100644
> --- a/hw/virtio/virtio-rng.c
> +++ b/hw/virtio/virtio-rng.c
> @@ -156,6 +156,19 @@ static void check_rate_limit(void *opaque)
> vrng->activate_timer = true;
> }
>
> +static void virtio_rng_set_status(VirtIODevice *vdev, uint8_t status)
> +{
> + VirtIORNG *vrng = VIRTIO_RNG(vdev);
> +
> + if (!vdev->vm_running) {
> + return;
> + }
> + vdev->status = status;
> +
> + /* Something changed, try to process buffers */
> + virtio_rng_process(vrng);
> +}
> +
> static void virtio_rng_device_realize(DeviceState *dev, Error **errp)
> {
> VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> @@ -261,6 +274,7 @@ static void virtio_rng_class_init(ObjectClass *klass,
> void *data)
> vdc->realize = virtio_rng_device_realize;
> vdc->unrealize = virtio_rng_device_unrealize;
> vdc->get_features = get_features;
> + vdc->set_status = virtio_rng_set_status;
> }
>
> static const TypeInfo virtio_rng_info = {
> --
> 2.14.3
>
>
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
