On Tue, 22 Feb 2022 10:42:55 +0100 Gerd Hoffmann <kra...@redhat.com> wrote:
> Hi, > > > > And the upstream code is now pretty much identical except for the > > > default; note that for TCG you do need to keep to 40 I think. > > > > will TCG work with 40bits on host that supports less than that? > > When I understand things correctly the problem is that the phys-bits > limit applies to the npt/ept tables too, effectively restricting guest > physical address space to host physical address space. > > TCG is not affected by that and should work just fine. > > Not sure what happens if you turn off npt/ept and run on softmmu. > Possibly that works fine too. > > > Also quick look at host-phys-bits shows that it affects only 'host' > > cpu model and is NOP for all other models. > > I don't think so. microvm forces host-phys-bits=on and that works with > all cpu models. I just don't see how host-phys-bits can work for other than 'host' cpu model. It's true that property is available for all cpu models, but the field it sets is only used in target/i386/host-cpu.c, the same applies to host-phys-bits-limit. Am I missing something? > > take care, > Gerd >
