Okay, I'm looking at this bug report related to QEMU. The issue is about live migration failing when using the CPU type 'qemu64'. The user reports an error stating that the guest CPU doesn't match and mentions a missing feature called 'abm'. First, I need to understand what each part means. Live migration in virtualization allows moving a running VM from one host to another without downtime. So if this fails, it's a significant issue. The error message says "guest CPU doesn't match specification: missing features: abm". The 'abm' likely stands for 'Advanced Bit Manipulation' instructions. These are specific CPU features that QEMU might be checking during migration. Looking at the steps to reproduce, they start a VM with 'qemu64' on an Intel Xeon E5-2620 v4 and then migrate it to another Xeon E5-2670. The migration fails because of the missing 'abm' feature. But when using '-cpu qemu64,abm=off', it works. So, why does this happen? It seems that QEMU is expecting certain CPU features (like abm) when configured with 'qemu64'. If the target CPU doesn't support these, migration fails. The user notes that this should work on generic CPUs, implying that maybe the feature shouldn't be required or handled differently. Looking at the possible categories: device, graphic, socket, network, KVM, boot, vnc, debug, files, permissions, performance, kernel, peripherals, hypervisor. The issue is about CPU features and live migration. Since it's related to how QEMU handles CPU configurations during migration, which involves the hypervisor layer (KVM in this case), I think 'hypervisor' is the right category. It's not a translation issue or assembly problem; it's more about how the hypervisor manages CPU feature sets during VM operations. hypervisor