Re: [libvirt] [PATCH 00/12] Autoselect a DRM node for egl-headless and add it to cmdline

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1628892. The problem is that we didn't put the DRI device into the namespace for QEMU to access, but that was only a part of the issue. The other part of the issue is that QEMU doesn't support specifying 'rendernode' for egl-headless yet (some patches to solve this are already upstream for 3.1, some are still waiting to be merged). Instead, QEMU's been autoselecting the DRI device on its own. There's no compelling reason for libvirt not doing that instead and thus prevent any permission-related issues. Unlike for SPICE though, I deliberately didn't add an XML attribute for users to select the rendernode for egl-headless, because: a) most of the time, users really don't care about which DRM node will be used and libvirt will most probably do a good decision

b) egl-headless is only useful until we have a remote OpenGL acceleration support within SPICE c) for SPICE (or for SDL for that matter at some point), the rendernode is specified as part of the <gl> subelement which says "if enabled, use OpenGL acceleration", but egl-headless graphics type essentially serves the same purpose, it's like having <gl enabled='yes'/> for SPICE, thus having a <gl> subelement for egl-headless type is rather confusing