------- Comment From [email protected] 2024-10-07 05:51 EDT------- Update on the root cause:
This bug is observed when at L1 level, vcpu->arch.vcore->lpcr has LPCR_MER set. This happens in the following situation: 1. When triggering a crash, a NMI is sent to a running vCPU that had LPCR_MER bit set. 2. In the NMI path, all registers are refreshed, i.e, H_GUEST_GET_STATE is called for all the registers. 3. When H_GUEST_GET_STATE is called for lpcr, the vcpu->arch.vcore->lpcr of that vCPU at L1 level gets updated with LPCR_MER set to 1, and this new value is always used whenever that vCPU runs, regardless of whether there was a pending interrupt. 4. Since LPCR_MER is set, the vCPU in L2 always jumps to the external interrupt handler, and this cycle never ends. The result is that any of the L2's VCPUs starts getting a flood of infinite spurious interrupts. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2077722 Title: [Ubuntu 24.04] MultiVM - L2 guest(s) running stress-ng getting stuck at booting after triggering crash To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-power-systems/+bug/2077722/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
