Re: [RFC v1 00/38] arm cleanup experiment for kvm-only build

[Claudio Fontana]

On 3/4/21 5:39 PM, Philippe Mathieu-Daudé wrote:
> On 3/3/21 7:54 PM, Richard Henderson wrote:
>> On 3/3/21 10:45 AM, Claudio Fontana wrote:
>>> It is a bit weird that qemu-system-aarch64 runs with a cortex-a15
>>> model tbh, as cortex-a15 is not capable of aarch64.
>>
>> No, but qemu-system-aarch64 is capable of 32-bit emulation (because most
>> 64-bit cpus retain 32-bit mode).  It takes no extra effort to run
>> cortex-a15 than it does a cortex-a57.
> 
> IIRC qemu-system-arm starts the aa64 cores in 32-bit mode, while
> qemu-system-aarch64 in 64-bit (this gave me trouble because the
> kernels for the raspi 64-bit SoCs are in 32-bit mode -- because
> the GPU starts them in this mode).
> 
>> I have wondered if we should have just one qemu-system-arm that does it
>> all and drop the separate qemu-system-aarch64 -- or vice versa.  But
>> we've had the separation around so long I'm sure someone would be confused.
> 
> That would be great cleanup IMHO.
> 

Would we still be able to configure a lean AARCH64-only qemu that only contains 
the cpu models we want,
(via board configuration / KConfig?),

for example, a kvm-only build that only has a few 64-bit cpu models in it, plus 
max/host and removes all the rest?

Ciao,

CLaudio