Re: [Qemu-devel] [PULL 5/5] hw/arm/virt: Support legacy -nic command line syntax

[Eric Auger <eric.auger@linaro.org>]

Hi Peter,
On 01/18/2016 02:34 PM, Peter Maydell wrote:
> On 18 January 2016 at 13:29, Eric Auger <eric.auger@linaro.org> wrote:
>> How is it supposed to live with Passthrough'ed NIC? Current way to
>> instantiate a VFIO platform NIC looks like:
>>
>> -device vfio-amd-xgbe,host=e0900000.xgmac
>> where vfio-amd-xgbe is the name of the VFIO AMD XGBE platform QEMU
>> device and e0900000.xgmac is the name of the device in
>> /sys/bus/platform/devices.
> 
>> Before that commit I was able to instantiate this VFIO device and got
>> networking working, testing it with ping. Now ping don't work anymore. I
>> Guess I now use this other default NIC?
>>
>> Curiously it does not seem to prevent networking with upstreamed Calxeda
>> Midway device and I did not figure why yet?
> 
> Hmm, I guess this is changing things in that we now will have a
> virtio PCI device appearing if you use the default (-net nic -net user)
> settings. But I don't see why that would particularly interfere
> with VFIO passthrough, except in as much as the guest now has
> two network cards in it and might be preferring one as eth0
> rather than the other...
Yes that's what currently happens I think. I get the slirp thing on eth0
and my passthrough'ed device on eth1. That's not very straightforward
for the end-user to get those 2 NIC's now. In case I passthrough some
NIC's I would have expected this default NIC not be instantiated?

Alex, how do you manage on x86 platforms with VFIO-PCI NIC?

Thanks

Eric
> 
> thanks
> -- PMM
>