------- Comment From [email protected] 2018-12-27 14:20 EDT------- Hello, I could reproduce this on Power9, in the following kernels: 4.15.0-20-generic 4.18.0-10-generic
I compiled kvm_pr for 4.18, and debbuged it until I found this: arch/powerpc/kvm/book3s_pr.c:2038 /* * PR KVM can work on POWER9 inside a guest partition * running in HPT mode. It can't work if we are using * radix translation (because radix provides no way for * a process to have unique translations in quadrant 3). */ if (cpu_has_feature(CPU_FTR_ARCH_300) && radix_enabled()) return -EIO; return 0; Here, cpu_has_feature(CPU_FTR_ARCH_300) returns: false for Power8, true for Power9. And radix_enabled() returns: false if bootargs contains "disable_radix", true otherwise. ## Meaning that, if one wants to load the kvm_pr module on a guest with Power9, the guest kernel must be booted with "disable_radix", as it looks like radix is the default choice. paelzer, please verify if your tests run with this parameter. ## BTW, it only works on vanilla kernel v4.18+. Before that, kvm_pr was just disabled for Power9. I am not sure about Ubuntu kernel including this patch on earlier kernels. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1778854 Title: kvm_pr on power9 not loadable To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-power-systems/+bug/1778854/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
