Re: [Qemu-devel] [PATCH 24/25] vmstate: port arm cpu

[Richard Henderson <rth@twiddle.net>]

On 10/25/2011 11:27 AM, Paul Brook wrote:
>> -    /* Avoid mode switch when restoring CPSR.  */
>> -    env->uncached_cpsr = val & CPSR_M;
>> -    cpsr_write(env, val, 0xffffffff);
>> +
>> +    env->uncached_cpsr = env->cpsr_vmstate & CPSR_M;
>> +    cpsr_write(env, env->cpsr_vmstate, 0xffffffff);
> 
> You've removed the helpful comment explaining why this wierdness exists. 
> Please put it back.
> 
> A comment in cpu.h explaining what cpsr_vmstate is for would also be nice.
> Specifically it's a hack[1] to transfer data between the pre_save/post_load 
> hooks and the vmstate machinery.  IMO "vmstate" is a sufficiently generic term 
> that it could be confused with some actual cpu register, especially once we 
> get round to implementing the hypervisor extensions.
> 
> Paul
> 
> [1] Maybe a necessary hack, but still a wart from requiring static table 
> driven vmstate descriptions.

I wonder if we shouldn't make it easier to do what I do for Alpha
with the rather different hack for the fpcr.

That might avoid some of the other pre/post_load hooks, and the
extra data fields that requires in the cpu structure.


r~