On 05/07/2015 02:36 AM, Pavel Fedin wrote: > Hello! > >> Yes. qemu-system-aarch64 -cpu cortex-a15 gets you a 32-bit Cortex-A15. This >> is >> exactly like the x86 QEMU, where you can emulate all the 32-bit x86 CPUs in >> qemu-system-x86_64. > > And what is the default in x86_64 ? I believe it's 64-bit CPU, and not i686, > isn't it ? > I agree that -cpu cortex-a15 might work with qemu-system-aarch64. But isn't > it expected to get the "native" CPU by default ? This behavior of qemu causes > weird thing with libvirt/virt-manager. I create a VM, specify "aarch64" as > architecture, and set "hypervisor default" as CPU model. With "hypervisor > default" libvirt does not pass any -cpu option to qemu, leaving it up to the > emulator (exactly as expected). So, i supply 64-bit kernel and rootfs, and > nothing works. I have to explicitly change the CPU to "cortex-a57". Isn't it > confusing to have such a default ? > This is even more confusing since currently i don't know any implementation > of aarch64 except A57 and A53 (which are the same from software point of > view). So, i believe, A57 is quite a reasonable default. >
FWIW virt-manager 1.2.0 (just released) will do the following when creating a new VM: - aarch64 + kvm : -cpu host - aarch64 + tcg : -cpu cortex-a57 - arm32 + kvm : -cpu host - arm32 + tcg : defer to qemu Though if you explicitly request 'hypervisor default' then we won't specify any -cpu and defer to qemu, which will hit the cortex-a15 default for aarch64 - Cole