Re: [Qemu-devel] [PATCH] Fix default CPU model for ARM64

[Peter Crosthwaite]

On Fri, May 8, 2015 at 12:14 AM, Pavel Fedin <address@hidden> wrote:
>  Hello!
>
>> 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
>
>  virt-manager is not the only tool to create VMs...
>  But, okay. Seems you just don't want to change this. Well... I still don't 
> agree and this
> default looks strange for me, but it's just me. I'm out of further arguments.
>

I think the real bug is the naming scheme for QEMU targets. QEMU
targets such as Aarch64 and x86_64 are following the long established
convention of using an ISA for a name, but are ultimately badly named
as they support multiple ISAs beyond what their singular name
suggests.

"qemu-system-arm" would be the be the best name for the
works-for-all-ARM QEMU but that name is taken. But if we are true to
qemu-system-aarch64 being a functional superset of arm, can we just
unify as the one arch ("arm") and phase out qemu-system-aarch64 (would
become an alias of qemu-system-arm)?. Linux user builds are the main
complication, but that is the case where it very much does make sense
to tie to an ISA. Ignoring legacy, the ideal naming scheme would be:

qemu-system-arm
aarch64-linux-user
aarch32-linux-user

Regards,
Peter

Regards,
Peter

> Kind regards,
> Pavel Fedin
> Expert Engineer
> Samsung Electronics Research center Russia
>
>
>