Re: [RFC QEMU PATCH] ui: Make the DisplayType enum entries conditional

On Wed, Jun 09, 2021 at 01:24:05PM +0200, Gerd Hoffmann wrote: > On Wed, Jun 09, 2021 at 12:02:40PM +0200, Thomas Huth wrote: > > Libvirt's "domcapabilities" command has a way to state whether > > certain graphic frontends are available in QEMU or not. Originally, > > libvirt looked at the "--help" output of the QEMU binary to determine > > whether SDL was available or not (by looking for the "-sdl" parameter > > in the help text), but since libvirt stopped doing this analysis of > > the help text, the detection of SDL is currently broken, see: > > > > https://bugzilla.redhat.com/show_bug.cgi?id=1790902 > > > > QEMU should provide a way via the QMP interface instead. The simplest > > way, without introducing additional commands, is to make the DisplayType > > enum entries conditional, so that the enum only contains the entries if > > the corresponding CONFIG_xxx switches have been set. > > Hmm, that'll break for the "dnf remove qemu-ui-sdl" case ... Note tht libvirt invalidates its cache of QEMU capabilities when it sees the /usr/lib64/qemu directory timestamp change. So it ought to pick up changes caused by installing/removing QEMU modules, and apply this to future queries for domcapabilities, or when starting future QEMU guests.