Hi Tim, you are right that neither of the workaround steps were necessary on 22.04 and they should neither be on 24.04.
### Topic 1 - changes that should not be needed Ubuntu 24.04 by default has 1. hugetlbfs mounted (was that no more the case for you after upgrade?) $ mount | grep huge hugetlbfs on /dev/hugepages type hugetlbfs (rw,nosuid,nodev,relatime,pagesize=2M) 2. uncommenting hugetlbfs_mount in /etc/libvirt/qemu.conf changes nothing default is #hugetlbfs_mount = "/dev/hugepages" Changing that to hugetlbfs_mount = "/dev/hugepages" will not change anything. I assume #1 and #2 have only been things on your try to debug what is wrong - which is fine. But let us know if it is otherwise. ### Topic 2 - was there an apparmor denial? Now back to your actual issue, you mentioned that you set apparmor to complain mode. Was there an indication that apparmor is the issue, a related denial in the syslog when you start your guest? If so could you please pass that denial? ### Topic 3 - repro seems to not trigger this I picked a guest which before had: <memory unit='MiB'>1024</memory> <currentMemory unit='MiB'>1024</currentMemory> And changed it to use huge pages by adding: <memoryBacking> <hugepages> <page size='2048' unit='KiB'/> </hugepages> </memoryBacking> To confirm it tries to use the right thing I started it without allocating huge pages and got: => qemu-system-x86_64: unable to map backing store for guest RAM: Cannot allocate memory Then I allocated some huge pages in the system and started it again. $ echo 512 | sudo tee -a /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages $ virsh start --console test Worked right away. I double checked in /proc/meminfo and saw HugePages_Free changing when the guest was running. So I think, something is configured in an unexpected way. Could you share - your full guest-config in regard to memory - hugeadm --list-all-mounts - journalctl -f while starting the guest - grep -i huge /proc/meminfo ** Changed in: libvirt (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2073214 Title: hugepages causes permissions error To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/2073214/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs