[Development] QRandomGenerator and boot times

[Sami Nurmenniemi]

On 15.09.2017 18:21, Thiago Macieira wrote:
> On Friday, 15 September 2017 00:31:36 PDT Sami Nurmenniemi wrote:
>> I think we'll just have to accept blocking for the devices without
>> hwrng. I don't know if we really support any such devices. If we do and
>> boot time is essential for those, we'll have to figure out some way
>> (probably saving entropy over reboot).
> And that would be a non-Qt job. I wasn't worried about Qt on real devices
> because I don't expect it to be run early enough to matter.  On VMs, that's
> another story, and if you don't trust your undercloud-provided /dev/hwrng, why
> are you using that cloud? (Though I'll say there's an Intel team working on
> figuring out how a VM can get trust from the actual hardware, skipping the
> hypervisor trust)
We have made some safety critical customer demos where fast boot time of 
Qt framework is essential. It was demoing boot time of 1.2s for a Qt 
application to start after powering on the device. I suppose that demo 
(and real safety critical use cases) is going to have problems with the 
QRandomGenerator even with hwrng in use.

>
> Anyway, I've read the entire Python thread to figure out what their conclusion
> was. Turns out, after spending hours reading everything, the bug ends without
> a conclusion. It must have been concluded, but it's not recorded in the bug
> report!
>