"Michael S. Tsirkin" <m...@redhat.com> writes: > On Tue, Dec 18, 2012 at 12:30:20PM +0100, KONRAD Frédéric wrote: >> On 18/12/2012 12:01, Michael S. Tsirkin wrote: >> >On Tue, Dec 18, 2012 at 10:33:37AM +0000, Peter Maydell wrote: >> >>On 17 December 2012 15:45, Michael S. Tsirkin <m...@redhat.com> wrote: >> >>>Is the point to allow virtio-mmio? Why can't virtio-mmio be just >> >>>another bus, like a pci bus, and another binding, like the virtio-pci >> >>>binding? >> >>(a) the current code is really not very nice because it's not >> >>actually a proper set of QOM/qdev devices >> >>(b) unlike PCI, you can't create sysbus devices on the >> >>command line, because they don't correspond to a user >> >>pluggable bit of hardware. We don't want users to have to know >> >>an address and IRQ number for each virtio-mmio device (especially >> >>since these are board specific); instead the board can create >> >>and wire up transport devices wherever is suitable, and the >> >>user just creates the backend (which is plugged into the virtio bus). >> >> >> >>-- PMM >> >This is what I am saying: create your own bus and put >> >your devices there. Allocate resources when you init >> >a device. >> > >> >Instead you seem to want to expose a virtio device as two devices to >> >user - if true this is not reasonable. >> > >> The modifications will be transparent to the user, as we will keep >> virtio-x-pci devices. > > Then what's the point of all this? > > -device virtio-pci,id=transport1 -device virtio-net,bus=transport1 > > or > > -device virtio-mmio,id=transport1 -device virtio-net,bus=transport1 > > Is simply an insane way to create a network device.
virtio-pci is pluggable into a bus, virtio-mmio is not. There is a fixed number of them for a specific board and you have the option to add virtio devices to the ones that already exist. virtio is a mess in its current state. Large swaths are not qdev'ified and we jump through hoops to try to set properties. I can't imagine how you can look at this cleanup and not understand why it's nicer... Regards, Anthony Liguori > > -- > MST