Re: State of contrib/vhost-user-input?

[Alex Bennée]

Alex Bennée <alex.bennee@linaro.org> writes:

> Marc-André Lureau <marcandre.lureau@redhat.com> writes:
>
>> Hi Alex
>>
>> On Mon, Oct 23, 2023 at 8:34 PM Alex Bennée <alex.bennee@linaro.org> wrote:
>>>
>>>
>>> Hi,
>>>
>>> I'm trying to get the contrib/vhost-user-input working but it exits
>>> during the boot up sequence:
>>>
<snip>
>>> Which looks like libvhost-user is expecting
>>> VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS to be negotiated and the
>>> resulting VHOST_USER_ADD_MEM_REG to be sent. How is this meant to work
>>> if the protocol feature isn't negotiated?
>>
>>
>> How did you start QEMU ? Did you forget to use shared memory ?
>
> I had:
>
>        -m 8192 \
>        -object memory-backend-memfd,id=mem,size=8G,share=on \
>
> Alongside:
>
>        -device virtio-gpu-pci \
>        -device qemu-xhci -device usb-kbd \
>        -kernel ~/lsrc/linux.git/builds/arm64/arch/arm64/boot/Image.gz
> -append 'console=ttyAMA0 root=/dev/sda2' \
>        -display gtk,gl=on \
>        -chardev socket,id=mouse2,path=/tmp/mouse.sock -device 
> vhost-user-input-pci,chardev=mouse2
>
> I even double checked with the generic device I was working with:
>
>        -chardev socket,id=mouse2,path=/tmp/mouse.sock -device
> vhost-user-device-pci,chardev=mouse2,virtio-id=18,config_size=136,num_vqs=2

Ahh but not the magic:

  -numa node,memdev=mem

>
>> We should probably add some error at QEMU level when vhost-user devices
>> are used without shared memory!
>
> That would certainly be a good idea.

Where would the best place to do this check be?

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro