Re: [Qemu-devel] Headsup: windows virtio networking does not work on current git

[Jason Wang <jasowang@redhat.com>]

On 02/02/2013 05:13 AM, Anthony Liguori wrote:
> Michael Tokarev <mjt@tls.msk.ru> writes:
>
>> 02.02.2013 00:36, Anthony Liguori wrote:
>>> Michael Tokarev <mjt@tls.msk.ru> writes:
>>>
>>>> 02.02.2013 00:18, Michael Tokarev wrote:
>>>>> Just a heads-up for now, no real diagnostics or anything like that.
>>>>>
>>>>> Current git master (a9c87c586ba9ee290792a98dc126b2861b7f8b03), when booted
>>>>> a windows guest, results in no virtio-net inside.  Neither winXP nor Win7,
>>>>> neither older nor latest (22 Jan 2013) virtio-net drivers works.
>>>>>
>>>>> Windows displays a yellow exclamation mark near the virtio-net device and
>>>>> says it can't start the device (Code 10).
>>>>>
>>>>> Linux guests work fine, quick test anyway.
>>>>>
>>>>> Cc'ing Jason since his virtio-net changes was last.  But I repeat: no
>>>>> diagnostics as of yet, no bisection.
>>>> Bisection was easy, since win works fine right before the multiqueue
>>>> virtio-net series.  This is the first bad commit:
>>> Adding Vadim and Michael.
>>>
>>> If you use -M pc-1.3 or explicitly disable multiqueue, does the driver work?
>> Neither one of these nor both makes any visible difference.
>> Neither does -M pc-1.1 (just in case).
> Hrm, then it's very likely not a driver problem.  Thanks.
>
> Regards,
>
> Anthony Liguori

Have a look at this issue. It was caused by multiqueue patch who adds a
new field to virtio_net_cfg. Not sure multiqueue is the root cause since
I also find even w/o multiqueue, adding any new field to virtio_net_cfg
will break windows guest. Haven't had a clue on this, will continue
investigate.
>
>>> Regards,
>>>
>>> Anthony Liguori
>>>
>>>> commit fed699f9ca6ae8a0fb62803334cf46fa64d1eb91
>>>> Author: Jason Wang <jasowang@redhat.com>
>>>> Date:   Wed Jan 30 19:12:39 2013 +0800
>>>>
>>>>       virtio-net: multiqueue support
>>>>
>>>>       This patch implements both userspace and vhost support for multiple queue
>>>>       virtio-net (VIRTIO_NET_F_MQ). This is done by introducing an array of
>>>>       VirtIONetQueue to VirtIONet.
>>>>
>>>>       Signed-off-by: Jason Wang <jasowang@redhat.com>
>>>>       Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
>>>>
>>>> After this commit, win guest (winXP and win7) shows yellow
>>>> exclamation sign and is unable to start the device with
>>>> code 10.
>>>>
>>>> FWIW.  I'm not sure it is a good idea to make a release with
>>>> such a breakage, even rc0.
>>>>
>>>> Thanks,
>>>>
>>>> /mjt
>