On 11/27/2017 01:56 PM, Cornelia Huck wrote: > On Fri, 24 Nov 2017 17:39:04 +0100 > Halil Pasic <pa...@linux.vnet.ibm.com> wrote: > >> On 11/24/2017 05:15 PM, Cornelia Huck wrote: >>>>> In theory this should work. >>>>> >>>>> In reality it seems more complicated. A per-device property is easy and >>>>> can be >>>>> inspected on the command line (e.g. -device virtio-blk-ccw,help), while a >>>>> new >>>>> machine property would require to change the qemu help output and >>>>> qemu-options >>>>> file (which makes it visible for all architectures). >>>> And then we have the fun of describing, that this property is weird, and >>>> can >>>> not be set, and it's value does not matter. >>> Well, that's the case for both, no? >> >> >> I don't think we have to document _device_ properites in qemu-options.hx >> I don't see any documented neither for virtio-ccw nor for vfio-ccw. The >> machine properties, on the contrary, are documented in this file. > > But not having to describe it does not make it any less weird. >
The user won't make big eyes should she read the documentation. The weirdness isn't less but is less exposed. >>> >>> (Unless we simply make this a "default cssid" prop after all - then it >>> would be more than just a simple indication for libvirt...) >>> >> >> We are now talking about the "cssid-unrestricted" property. The default >> cssid is not something I would like to do any time soon. > > What's so bad about this? As said above, I think it would be much more > useful. If libvirt can detect r/o vs. r/w for properties, we can simply > start out with a r/o variant now... > I'm not sure I understand you. Are you proposing the following: Drop the restriction, but don't indicate this via a read only "cssid-unrestricted" device property but via a "default-css" read only machine property. Libvirt then should know that if "default-css" is present then we don't have this virtual into 0xfe and non virtual into 0xfd restriction any more. Please confirm that I understood correctly or describe your idea more verbosely.