Re: [RFC v3 1/8] cpu-timers, icount: new modules

[Paolo Bonzini]

On 04/08/20 10:13, Claudio Fontana wrote:
>> -        if (mem && use_icount && dbs->dir == DMA_DIRECTION_FROM_DEVICE) {
>> +        if (mem && icount_enabled() && dbs->dir == 
>> DMA_DIRECTION_FROM_DEVICE) {
> 
> 
> 
> In this specific case, where dma_blk_cb() changes its behaviour to be more 
> deterministic
> if icount_enabled(),
> 
> do you think that if qtest_enabled() we should also follow the more 
> deterministic path,
> or should we go through the "normal" path instead, as this patch does?
> 
> Tests pass in any case, but I wonder what would be the best behavior for 
> qtest accel in this case.
> (Maybe Pavel?)

No, qtests simply should not use SG lists that cause the problematic
nondeterminism.  We don't have that luxury for guests.

Paolo