On 03/21/19 18:58, Peter Maydell wrote: > On Thu, 21 Mar 2019 at 17:35, Laszlo Ersek <lersek@xxxxxxxxxx> wrote: >> It simply keeps the status quo from before the patchset. >> >> The specific emulation targets that virtio-vga should not be enabled for >> (regardless of other targets / machine types) are arm/aarch64. IOW, in >> the longer term, it's not that virtio-vga is suitable only for PC || >> DINO || PSERIES, but that it's *not* suitable for arm/aarch64. > > Relying on the device not being present for aarch64 seems > fragile to me. It will break if we add a different > aarch64 machine other than "virt" and want that other > machine to have virtio-vga. It will also break if we > ever manage to get full heterogenous-CPU support and > end up with a single qemu-system binary that can emulate > both AArch64 virt and x86-64 pc machines :-) > > If what you want is "don't use virtio-vga when using KVM > on aarch64" then why not have logic that implements that? That's actually the logic that I implemented originally (or something very close to it -- <https://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=706b5b627719e95a33606c463bc83c841c7b5b0e>), but since then, this code has been modified in libvirt multiple times: * [PATCH v2 00/17] cleanups and improvements for video device code https://www.redhat.com/archives/libvir-list/2016-October/msg00533.html https://libvirt.org/git/?p=libvirt.git;a=shortlog;hp=a62655f9c33a8f7c6257779ddbdbf1352d53a526;h=fb8f3b1c22c8f272bb9a47e8f8915acc3cfb47f1 * [PATCH v3 0/6] Add support for video and input devices on S390 https://www.redhat.com/archives/libvir-list/2018-March/msg01519.html https://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=4bbf7f8cb5bf979ea2f5c247b2ddb884a07ac33f I'm not implying that those patches must have introduced a libvirt regression, I just agree that the code deserves investigation. This is why I added libvir-list to the CC list when reporting the problem. > For 4.0 we should definitely just retain what we had > before the introduction of KConfig, but as a general > thing we should look to not have to have this odd > wrinkle. > > (AFAIK virtio-vga is no different in this regard to the other > vga PCI devices, which also won't work in KVM setups.) I agree -- please refer to the "domcapabilities" part (1) of my report: https://lists.gnu.org/archive/html/qemu-devel/2019-03/msg06060.html > @@ -92,6 +92,8 @@ > <video supported='yes'> > <enum name='modelType'> > <value>vga</value> > + <value>cirrus</value> > + <value>vmvga</value> > <value>virtio</value> > </enum> > </video> "cirrus" and "vmvga" look wrong for aarch64. Thanks Laszlo -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
