Re: [PATCH] vl: transform QemuOpts device to JSON syntax device

[Peter Krempa]

On Thu, Feb 24, 2022 at 09:02:02 +0000, Daniel P. Berrangé wrote:
> On Thu, Feb 24, 2022 at 02:06:53PM +0800, Zhenzhong Duan wrote:
> > While there are mixed use of traditional -device option and JSON
> > syntax option, QEMU reports conflict, e.x:
> > 
> > /usr/libexec/qemu-kvm -nodefaults \
> >   -device 
> > '{"driver":"virtio-scsi-pci","id":"scsi0","bus":"pci.0","addr":"0x02.0"}' \
> >   -device virtio-scsi-pci,id=scsi1,bus=pci.0
> 
> Why are you attempting to mix JSON and non-JSON syntax at the same
> time ? The expectation is that any mgmt app adopting JSON syntax
> will do so universally and not mix old and new syntax. So in practice
> the scenario above is not one that QEMU ever intended to have used
> by apps.

Based on the previous post they are using some 'qemu:commandline'
overrides with the legacy syntax with new libvirt which uses JSON
syntax:

<qemu:commandline>
  <qemu:arg value='-netdev'/>
    <qemu:arg value='user,id=mynet0,hostfwd=tcp::44483-:22'/>
    <qemu:arg value='-device'/>
  <qemu:arg 
value='virtio-net-pci,netdev=mynet0,mac=00:16:3E:68:00:10,romfile='/>
</qemu:commandline>

I suggested that they should add the required functionality to libvirt
instead of trying to hack qemu:

https://lists.gnu.org/archive/html/qemu-devel/2022-02/msg05068.html