2014-02-17 11:38 GMT+01:00 Paolo Bonzini <[email protected]>:
> Il 17/02/2014 11:01, Alex David ha scritto:
>
> I indeed don't use paravirtualization.
>>
>
> Virtio _is_ paravirtualization. :)
>
>
Ok, now that seems much more understandable... I missed that point ha.
>
> I'm emulating a bunch of sensors/actuators.
>>
>> If I virtualize my sensors and attach them to the i2c-dev with -device,
>> how do I get those data on the host then ?
>>
>
> It depends on your use case.
>
> It could be that you can make them return a constant value.
>
> Otherwise, you may want to use a chardev for that purpose, or finally a
> QOM (QEMU Object Model) property. For example, add
>
> CONFIG_TMP105=y
>
> to default-configs/x86_64-softmmu.mak before building QEMU, then do the
> following (indented = in the guest):
>
> $ x86_64-softmmu/qemu-system-x86_64 --enable-kvm ~/test2.img -m 256 \
> -device tmp105,id=sensor,address=0x50 \
> -qmp unix:$HOME/qmp.sock,server,nowait
> $ qmp/qom-list -s ~/qmp.sock /machine/peripheral/sensor
> temperature
> @parent_bus/
> address
> hotpluggable
> realized
> type
> $ scripts/qmp/qmp-shell ~/qmp.sock
> (QEMU) qom-get path=/machine/peripheral/sensor property=temperature
> {u'return': 0}
> (QEMU) qom-get path=sensor property=address
> {u'return': 80}
>
> # modprobe i2c-dev
> # i2cget -y 0 0x50 0 w
> 0x0000
>
> (QEMU) qom-set path=sensor property=temperature value=20000
> {u'return': {}}
>
> # i2cget -y 0 0x50 0 w
> 0x0014
>
> For this particular sensor, you have to swap the two bytes and the result
> is 8.8 fixed-point.
>
> Paolo
>
>
> Thanks for your help. As you may see, I'm not that experienced in
>> QEMU/Linux kernel.
>>
>
>
Ok, I'm gonna try these things. I might try to use a chardev also. Thanks
for your help !
