On Tue, Mar 01, 2022 at 04:16:25PM +0000, Peter Maydell wrote: > On Tue, 1 Mar 2022 at 16:08, Peter Maydell <peter.mayd...@linaro.org> wrote: > > > > On Wed, 23 Feb 2022 at 22:31, Richard Henderson > > <richard.hender...@linaro.org> wrote: > > > > > > Changes for v3: > > > * Update emulation.rst. > > > * Split out separate update to ID_AA64MMFR0. > > > * Hack for avocado. > > > > > > If the avocado hack isn't acceptable, perhaps just drop the > > > last two patches for now? > > > > I think that given that there are Linux kernels out there > > that won't boot if LPA2 is enabled, we should probably have > > a -cpu command line option to disable it. Otherwise we might > > get a bunch of "why did my kernel stop booting" bug reports. > > ...and should using a versioned machine type also default > -cpu max to not enabling that? Not sure what x86 or other > precedent is there.
I don't recall us coming across an important scenario where a guest would fail to boot when we /enable/ a given CPU feature on x86, requiring us to hide it from -cpu max/host. Assuming the QEMU/KVM implementation of a CPU feature is correct per the relevant spec, then artificially hiding it by default from -cpu max feels questionable, as that penalizes non-buggy guest OS. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
