On 24.03.2017 11:09, Peter Maydell wrote: > On 24 March 2017 at 08:23, Juergen Gross <jgr...@suse.com> wrote: >> On 23/03/17 22:28, Eduardo Habkost wrote: >>> The xen-backend devices created by the Xen code are not supposed >>> to be treated as dynamic sysbus devices. This is an attempt to >>> change that and see what happens, but I couldn't test it because >>> I don't have a Xen host set up. >>> >>> If this patch breaks anything, this means we have a bug in >>> foreach_dynamic_sysbus_device(), which is supposed to return only >>> devices created using -device. >>> >>> The original code that sets has_dynamic_sysbus was added by >>> commit 3a6c9172ac5951e6dac2b3f6cbce3cfccdec5894, but I don't see >>> any comment explaining why it was necessary. >> >> xen-backend devices are created via qmp commands when attaching new >> pv-devices to a domain. They can be dynamically removed, too. Setting >> has_dynamic_sysbus was necessary to support this feature. > > This seems like it ought to be handled by marking the xen-backend > devices as being ok-to-dynamically-create somehow, not by marking > the machine as supporting dynamic-sysbus (which it doesn't). > Maybe we don't have the necessary support code to do that though?
Do the xen devices have to be sysbus devices? If no, I think you could change them to be of type TYPE_DEVICE nowadays - TYPE_DEVICE can be instantiated with "-device" nowadays, too. That's what we do with the spapr-rng device for example (see hw/ppc/spapr_rng.c). Thomas
