[Qemu-devel] q35 and sysbus devices

[Eduardo Habkost <ehabkost@redhat.com>]

Hi,

I am investigating the current status of has_dynamic_sysbus and
sysbus device support on each of QEMU's machine types. The good
news is that almost all has_dynamic_sysbus=1 machines have their
own internal (often short) whitelist of supported sysbus device
types, and automatically reject unsupported devices.

...except for q35.

q35 currently accepts all sys-bus-device subtypes on "-device",
and today this includes the following 23 devices:

* allwinner-ahci
* amd-iommu
* cfi.pflash01
* esp
* fw_cfg_io
* fw_cfg_mem
* generic-sdhci
* hpet
* intel-iommu
* ioapic
* isabus-bridge
* kvmclock
* kvm-ioapic
* kvmvapic
* SUNW,fdtwo
* sysbus-ahci
* sysbus-fdc
* sysbus-ohci
* unimplemented-device
* virtio-mmio
* xen-backend
* xen-sysdev

My question is: do all those devices really make sense to be used
with "-device" on q35? Should we make q35 validate dynamic sysbus
devices against a whitelist, like the other has_dynamic_sysbus
machines?

I'm asking this because I will resume work on the
"query-device-slots" command, which will report supported sysbus
devices too. And I don't want the new command to report any
devices that it shouldn't.

-- 
Eduardo