------- Comment From [email protected] 2026-08-31 01:52 EDT------- Hi Team,
I have tested this bug with qemu patchs posted by Amit, and upstream linux kernel, The issue is Not reproducible. OS Ubuntu 26.10 (Stonking Stingray) qemu-system-ppc64 --version QEMU emulator version 11.1.50 (v8.0.0-29343-g869a938207) uname -a Linux ubuntu 7.2.0+ #1 SMP PREEMPT_DYNAMIC Thu Aug 27 13:22:02 UTC 2026 ppc64le GNU/Linux Power 10 compatibility mode root@ubuntu:~# lscpu Architecture: ppc64le Byte Order: Little Endian CPU(s): 16 On-line CPU(s) list: 0-15 Model name: POWER10 (architected), altivec supported Model: 2.0 (pvr 0082 0200) Thread(s) per core: 8 Core(s) per socket: 2 Socket(s): 1 Virtualization features: Hypervisor vendor: pHyp Virtualization type: para -------- Steps Performed ------- 1. Install ubuntu 26.10 on a Power11 Lpar. 2. Change the compatibility mode of lpar to Power 10 from HMC 3. check model name, it should show as Power 10 in lscpu command 4. Start a guest in P10 compat mode, Guest should start and boot properly. 5. Guest boot was successful and i am able to login to the guest. -------- guest logs --------- Ubuntu Stonking Stingray (development branch) ubuntu-server hvc0 connecting... ^[[42;1R^[[42;83RPlease remove the installation medium, then press ENTER: [ 530.920533] (sd-umoun[14084]: Failed to unmount /run/shutdown/mounts/5f222a50d05d26db: Device or resource busy [ 530.922935] (sd-umoun[14085]: Failed to unmount /run/shutdown/mounts/c99926a0aece8251: Device or resource busy [ 530.926286] shutdown[1]: Could not detach loopback /dev/loop3: Device or resource busy [ 530.926846] shutdown[1]: Could not detach loopback /dev/loop2: Device or resource busy [ 530.927416] shutdown[1]: Could not detach loopback /dev/loop1: Device or resource busy [ 530.928021] shutdown[1]: Could not detach loopback /dev/loop0: Device or resource busy [ 530.929514] shutdown[1]: Unable to finalize remaining file systems, loop devices, ignoring. [ 530.937941] reboot: Restarting system Domain creation completed. Restarting guest. Running text console command: virsh --connect qemu:///system console ubuntu Authorization not available. Check if polkit service is running or see debug message for more information. Connected to domain 'ubuntu' Escape character is ^] (Ctrl + ]) guest login: guest Password: Welcome to Ubuntu Stonking Stingray (development branch) (GNU/Linux 7.0.0-14-generic ppc64le) * Documentation: https://docs.ubuntu.com * Management: https://landscape.canonical.com * Support: https://ubuntu.com/pro System information as of Fri Aug 28 08:03:59 PM UTC 2026 System load: 0.0 Processes: 229 Usage of /: 26.7% of 9.75GB Users logged in: 0 Memory usage: 6% IPv4 address for enp0s1: 192.168.122.239 Swap usage: 0% 0 updates can be applied immediately. The programs included with the Ubuntu system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. guest@guest:~$ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host noprefixroute valid_lft forever preferred_lft forever 2: enp0s1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 52:54:00:db:f9:c0 brd ff:ff:ff:ff:ff:ff altname enx525400dbf9c0 inet 192.168.122.239/24 metric 100 brd 192.168.122.255 scope global dynamic enp0s1 valid_lft 3580sec preferred_lft 3580sec inet6 fe80::5054:ff:fedb:f9c0/64 scope link proto kernel_ll valid_lft forever preferred_lft forever guest@guest:~$guest@guest:~$ lscpu Architecture: ppc64le Byte Order: Little Endian CPU(s): 10 On-line CPU(s) list: 0-9 Model name: POWER10 (architected), altivec supported Model: 2.0 (pvr 0082 0200) Thread(s) per core: 1 Core(s) per socket: 10 Socket(s): 1 Virtualization features: Hypervisor vendor: KVM Virtualization type: para -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2163620 Title: [Ubuntu 26.10] : KVM guest boot hangs on POWER11 host when processor compatibility mode is set to POWER10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2163620/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
