Public bug reported: == Comment: #0 - Satheesh Rajendran <sathe...@in.ibm.com> - 2018-02-20 02:07:45 == ---Problem Description--- Power9 Can't set 8 threads per core for Power9 guest and doing it so breaks vcpu hotplug further.
---uname output--- 4.15.0-10-generic Machine Type = power9 boston 2.2 (pvr 004e 1202) ---Debugger--- A debugger is not configured ---Steps to Reproduce--- 1. Boot a power9 guest with current vcpus=8 and threads=8 and maxvcpu 16. -- There is libvirt blocker, BUG 164807 , currently using workaround suggested as in https://bugzilla.linux.ibm.com/show_bug.cgi?id=164807#c3 to boot guest 2. Check vcpucount, vcpuinfo output, it shows 8 vcpus 3. Check vcpus inside guest, it shows only 4 vcpus and monitor info cpus says remanining 4 are halted. 4. Try vcpuhotplug, it fails inside the guest with below error [ 108.130338] Unable to find space in cpu_present_mask for processor <NULL> with 8 thread(s) .. <vcpu placement='static' current='8'>16</vcpu> <resource> <partition>/machine</partition> </resource> <os> <type arch='ppc64le' machine='pseries-bionic'>hvm</type> <boot dev='hd'/> </os> <cpu> <topology sockets='1' cores='2' threads='8'/> </cpu> ... 1)# virsh start vm1 2)# virsh vcpucount vm1 maximum config 16 maximum live 16 current config 8 current live 8 3)# virsh vcpucount vm1 --guest 4 ---------------------------------------------------NOK # virsh qemu-monitor-command vm1 --hmp --cmd "info cpus" * CPU #0: nip=0xc0000000000b5b1c thread_id=63461 CPU #1: nip=0xc0000000000b5b1c thread_id=63463 CPU #2: nip=0xc0000000000b5b1c thread_id=63464 CPU #3: nip=0xc0000000000b5b1c thread_id=63465 CPU #4: nip=0x0000000000000100 (halted) thread_id=63466 CPU #5: nip=0x0000000000000100 (halted) thread_id=63467 CPU #6: nip=0x0000000000000100 (halted) thread_id=63468 CPU #7: nip=0x0000000000000100 (halted) thread_id=63469 4) Hotplug vcpus # virsh setvcpus vm1 16 --live root@ltc-boston8:~# virsh vcpucount vm1 --guest 4 --------------------------------------------------------------------------NOK guest dmesg: [ 127.031090] Unable to find space in cpu_present_mask for processor <NULL> with 8 thread(s) root@ub Contact Information = sathe...@in.ibm.com Userspace tool common name: ii qemu-kvm 1:2.11+dfsg-1ubuntu1 The userspace tool has the following bit modes: both Userspace rpm: ii qemu-kvm 1:2.11 +dfsg-1ubuntu1 Userspace tool obtained from project website: na *Additional Instructions for sathe...@in.ibm.com: -Post a private note with access information to the machine that the bug is occuring on. -Attach ltrace and strace of userspace application. == Comment: #1 - Satheesh Rajendran <sathe...@in.ibm.com> - 2018-02-20 02:10:51 == Fix in upstream @ https://git.qemu.org/gitweb.cgi?p=qemu.git;a=history;f=target/ppc/compat.c;hb=03ee51d3548f5f553a3089f466483c1c6d5c666b == Comment: #2 - SRIKANTH AITHAL <bssrika...@in.ibm.com> - 2018-02-20 02:21:04 == Please mirror this to ubuntu and request to include patch in previous comment. ** Affects: ubuntu-power-systems Importance: Undecided Status: New ** Affects: qemu (Ubuntu) Importance: Undecided Assignee: Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) Status: New ** Tags: architecture-ppc64le bugnameltc-164861 severity-critical targetmilestone-inin--- ** Tags added: architecture-ppc64le bugnameltc-164861 severity-critical targetmilestone-inin--- -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1750526 Title: [Power9][Ubuntu 18.04] Can't set 8 threads per core for Power9 guest and doing it so breaks vcpu hotplug further.(kvm) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-power-systems/+bug/1750526/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
