Re: [Qemu-arm] [Qemu-devel] [Help]: Does qemu-system-aarch64 support virtio-9p? I got a problem when remap host file to guest in AArch64.

[Claudio Fontana]

On 05.08.2016 12:27, Claudio Fontana wrote:
> Hi,
> 
> On 05.08.2016 10:28, Daniel P. Berrange wrote:
>> On Fri, Aug 05, 2016 at 10:23:58AM +0800, Kevin Zhao wrote:
>>> Hi All,
>>>      I have a problem may about Qemu and kindly need your help. Does
>>> qemu-system-aarch64 support virtio-9p ?
>>>      Recently I have tried to use qemu remapped the file from host to
>>> guest. As I know, Qemu has supported this so long as guest kernel has
>>> support 9p(virtfs). Reference to this link:
>>> http://wiki.qemu.org/Documentation/9psetup
>>> Fedora 24 AArch64 kernel has supported this:
>>> address@hidden ~]# lsmod | grep 9p
>>> 9p                     56273  0
>>> fscache                87449  1 9p
>>> 9pnet_virtio            9122  0
>>> 9pnet                  83564  2 9p,9pnet_virtio
>>> virtio_ring            13866  5 virtio_net,virtio_pci,9pnet_
>>> virtio,virtio_mmio,virtio_scsi
>>> virtio                  9467  5 virtio_net,virtio_pci,9pnet_
>>> virtio,virtio_mmio,virtio_scsi
>>>
>>>     Now I use virsh to launch the VM, and the corresponding qemu command I
>>> have pasted here:
>>> http://paste.openstack.org/show/549225/.
>>>     You can see that:
>>> * -fsdev
>>> local,security_model=mapped,id=fsdev-fs0,path=/var/lib/libvirt/images/coreos
>>> -device
>>> virtio-9p-pci,id=fs0,fsdev=fsdev-fs0,mount_tag=share,bus=pci.2,addr=0x1*
>>>      Here is the command that remapped the directory from host to guest.
>>> After VM launched, I use the command to mount:
>>> * mount -t 9p -o trans=virtio share /tmp/shared/
>>> -oversion=9p2000.L,posixacl,cache=loose*
>>> But mount command will be blocked and output nothing.
>>
>> Try using  version=9p2000.u instead - I've noticed other versions have
>> been buggy in various kernel version/qemu version combinations. The
>> 9p2000.u version is what i use in libvirt-sandobx and so I know it will
>> work in general.
> 
> We are using version=9p2000.L here with qemu-system-aarch64, and it works 
> well.
> We tested only on qemu-2.5 though.

Forgot to mention though that we backported commit c8225aa1 "virtio-9p: use 
accessor to get thread_pool" though,
as without it we have experienced crashes.

Ciao, C.