> Interesting; I thought this was supposed to work. Exactly that was my thought when triaging it initially Furthermore I assume people working la57 (https://lwn.net/Articles/730925/) and such ran tests on much bigger sizes.
> Ah right Dan, if you're seeing the 40 bits physical in the guest you definitely need to try the flags I suggest in comment 6; host-phys- bits=true should work for you. I tested Bionic to be at least on libvirt 4.0 / qemu 2.11.1 when we want to check things under the "supposed to work now" flag. Defaults: Host: address sizes : 46 bits physical, 48 bits virtual Guest: address sizes : 40 bits physical, 48 bits virtual I ensured that with option -cpu host,host-phys-bits=true set I successfully get what my host can provide in the guest: Guest: address sizes : 46 bits physical, 48 bits virtual Starting a guest with that >1TB (that would be mostly on swap if needed) works just fine as expected. Here ~1063 GB from /proc/meminfo MemTotal: 1114676492 kB I also checked a more compatible approach like -cpu qemu64,phys-bits=42 and that works as well. IMHO - if anything - one could argue that libvirt/qemu could be smarter about e.g. auto adding those arguments (or print a warning) when crossing a certain memory size. So for now I'd stick to the "actually works" summary and keep the status to incomplete. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1769053 Title: Cannot start a guest with more than 1TB of RAM To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1769053/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
