On 05/03/13 17:48, Alexander Graf wrote:
> On 02/06/2013 12:47 AM, Jesse Larrew wrote:
>> Currently, the config size for virtio devices is hard coded. When a new
>> feature is added that changes the config size, drivers that assume a static
>> config size will break. For purposes of backward compatibility, there needs
>> to be a way to inform drivers of the config size needed to accommodate the
>> set of features enabled.
>>
>> Signed-off-by: Jesse Larrew<jlar...@linux.vnet.ibm.com>
>
> The following patch gets my s390 virtio guest working again, but I doubt it's
> the right fix.
>
> What is the expected dependency chain of feature calls?
>
>
> Alex
>
> diff --git a/hw/s390x/s390-virtio-bus.c b/hw/s390x/s390-virtio-bus.c
> index 089ed92..81be971 100644
> --- a/hw/s390x/s390-virtio-bus.c
> +++ b/hw/s390x/s390-virtio-bus.c
> @@ -154,7 +154,7 @@ static int s390_virtio_net_init(VirtIOS390Device *dev)
> VirtIODevice *vdev;
>
> vdev = virtio_net_init((DeviceState *)dev, &dev->nic, &dev->net,
> - dev->host_features);
> + dev->host_features | (1 << VIRTIO_NET_F_MAC));
> if (!vdev) {
> return -1;
> }
>
>
Actually this goes back to
commit 1e89ad5b00ba0426d4e949c9e6ce2926c15b81b7
Author: Anthony Liguori <aligu...@us.ibm.com>
Date: Tue Feb 5 17:47:15 2013 -0600
virtio-net: pass host features to virtio_net_init
Signed-off-by: Anthony Liguori <aligu...@us.ibm.com>
virtio-s390 calls virtio_net_init before it actually queries the
dev->features into
the host_features. virtio-ccw does the same, but it does not BUG. (Its still
wrong IMHO)
Same for virtio-pci:
static int virtio_net_init_pci(PCIDevice *pci_dev)
{
VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);
VirtIODevice *vdev;
vdev = virtio_net_init(&pci_dev->qdev, &proxy->nic, &proxy->net,
proxy->host_features); <--- use host_feature
vdev->nvectors = proxy->nvectors;
virtio_init_pci(proxy, vdev); <------------- actually gets host_feature
(!)
[..]
Good that my old rusty virtio-ccw transport has lots of BUG_ONS :-)
