On Fri, 23 Feb 2018 09:53:22 +0100 Gerd Hoffmann <kra...@redhat.com> wrote:
> Hi, > > > > What type of device is only sometimes hotpluggable ? > > > The commit message says "display devices" and "consoles", > > > but I would expect those to both be types of device which > > > have a class which is never hotpluggable, so you can mark > > > them non-hotpluggable with the existing class flag rather > > > than needing a per-instance flag. > > > > With this series, a vfio-pci device optionally supports a display. The > > vfio-pci device is hotpluggable, but QEMU display support is not. So > > the solution here is to make the vfio-pci device non-hotpluggable only > > when it supports and enables a display. > > > > Gerd, is there another solution that the display object is instantiated > > separately from the vfio-pci object and the display support in the > > vfio-pci device references the display object via an id. > > Well, not really. At least not without putting much of qemu display > support upside down. The qemu display (aka QemuConsole) is created and > managed by the display devices, they can't be created independant from > a device ... > > The connection between QemuConsole and User Interface (i.e. gtk, spice, > ...) is a bit more flexible. But also not really designed for hotplug > as QemuConsole is not hotpluggable in the first place ... > > We could drop the display property and use two devices instead. > > new vfio-pci would behave like display=off with this series. > added vfio-pci-display has display=on behavior. > display=auto is not possible. I expect libvirt and above would balk at creating a separate QEMU device for this purpose, easy for QEMU, hard for anything that manages QEMU. Thanks, Alex
