Re: [libvirt] Question about virtio-pci in Aarch64
Hi Cole,
Long time no see~
Thanks for giving help me about AArch64 of virtio-pci. You have rich
experience about this,
I am green hand and seeking for your help again :-)
On 13 June 2016 at 06:21, Cole Robinson <crobinso(a)redhat.com> wrote:
On 06/12/2016 10:29 AM, Kevin Zhao wrote:
> Hi Cole && All,
> Nice meeting you in the libvirt mail-list. Greetings from Linaro !!!
> I am Kevin Zhao from Linaro and working for OpenStack on Aarch64.
> Nowadays I find that the default "virtio" bus is "virtio-mmio" ,
not
> "virtio-pci". Since virtio-mmio do not has the host plugged function ,
> something is wrong with the function in OpenStack Nova.
>
> Then I search and find some mail information as belows by Cole :-)
> 1) https://www.redhat.com/archives/libvir-list/2015-December/
msg00217.html
> 2) https://www.redhat.com/archives/libvir-list/2016-March/
msg00167.html
>
> I see some efforts have been doing by you. Really thanks for your
> efforts for Aarch64. And I have some small questions.
> 1. Is Libvirt planning to replace the default virtio-mmio to
virtio-pci
> for Aarch64?
We have vague plans to maybe change the virtio-mmio default to virtio-pci
at
some future point, based on some new enough qemu machine type. But the main
blocker is that most linux distributions currently don't work out of the
box
with virtio-pci, at least Fedora doesn't as far as I know. So changing the
default now is pre-mature
2. If not , how can I change the xml file(generated by Virsh)
for
> virtio-pci so that Qemu can recognize it ?
>
The latest libvirt-1.3.5 release accepts device XML containing <address
type='pci'/> . The address block is an explicit request to libvirt to
'allocate a PCI address' rather than the default virtio-mmio. So for
example
if you want to specify a virtio nic, but have it use virtio-pci rather than
virtio-mmio, you can do something like:
<interface type='network'>
<source network='default'/>
<model type='virtio'/>
<address type='pci'/>
</interface>
I have changed the libvirt to 1.3.5 now, also add the pci to net-device xml
like:
<address type='pci'/>,then use the virsh to boot the VM,the total xml file
is:
https://paste.fedoraproject.org/409534/71434141/
After booting, the eth0 device disappear(eth0 occur when the address is
virtio-mmio),
but I can find another net-device, also it can't work for dhcp:
2: enp2s1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
link/ether 52:54:00:0d:25:26 brd ff:ff:ff:ff:ff:ff
inet6 fe80::5054:ff:fe0d:2526/64 scope link
valid_lft forever preferred_lft forever
Running lspci:
02:01.0 Ethernet controller: Red Hat, Inc Virtio network device
My question is:
1. I use Debian 8 AArch64 as the Guest OS, do you think the virtio-pci for
net-device works is OK ?
2. If I change the disk address-type to pci(Libvirt pass the virtio pci
parameters to Qemu for disk device), but I can't boot
the VM. Does Qemu not support virtio pci for disk device in AArch64?
Big Big Thanks~
But there isn't currently any switch to say 'always give me virtio-pci
instead
of virtio-mmio'
- Cole
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