RE: Some questions about virtio-net on Xen x86

[Jiamei Xie <Jiamei.Xie@xxxxxxx>]

Hi Anthony,

-----Original Message-----
From: Anthony PERARD <anthony.perard@xxxxxxxxxx> 
Sent: 2021年8月19日 22:16
To: Jiamei Xie <Jiamei.Xie@xxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx; Wei Chen <Wei.Chen@xxxxxxx>; nd <nd@xxxxxxx>
Subject: Re: Some questions about virtio-net on Xen x86

On Thu, Aug 19, 2021 at 10:38:49AM +0000, Jiamei Xie wrote:
> Hi all,
> I tried to run virtio-net on X86 machine according to the Wiki page 
> https://wiki.xenproject.org/wiki/Virtio_On_Xen. 
> And I Encountered some confusing problems.
> 
> It seems eth0 is not virtio-net, properly a pv-net. I am really confused.
> 
>  I have the following questions:
> 1. Does Xen x86 still support virtio-net based on QEMU backend?

Well, we don't test it, and the libxl toolstack doesn't really help getting 
virtio devices.

> 2. If yes, is there anything wrong in my guest config file?

The wiki state that you should add 'xen_emul_unplug=never' to the guest 
kernel's command line. (That would be "extra" in your guest.cfg.) I think that 
will prevent the virtio-net device from been unplug, and so you will see the 
virtio-net device in the guest.

But since libxl create Xen PV device anyway, you'll still have the Xen PV NIC, 
so two NICs with the same MAC.

I hope that help,

--
Anthony PERARD

Your answer helped me a lot, thank you very much. After adding 
'xen_emul_unplug=never', virtio-net can work normally.
I can see the virtio net device with lspci command.
00:00.0 Host bridge: Intel Corporation 440FX - 82441FX PMC [Natoma] (rev 02)
00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II]
00:01.1 IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II]
00:01.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 03)
00:02.0 Unassigned class [ff80]: XenSource, Inc. Xen Platform Device (rev 01)
00:03.0 SCSI storage controller: Broadcom / LSI 53c895a
00:04.0 VGA compatible controller: Cirrus Logic GD 5446
00:05.0 Ethernet controller: Red Hat, Inc. Virtio network device

Best wishes
Jiamei Xie