[PATCH 4/4] powerpc/xive: prepare all hcalls to support long busy delays

[Michael Ellerman]

Benjamin Herrenschmidt <benh at kernel.crashing.org> writes:
> On Fri, 2018-05-04 at 20:42 +1000, Michael Ellerman wrote:
>> Cédric Le Goater <clg at kaod.org> writes:
>> 
>> > This is not the case for the moment, but future releases of pHyp might
>> > need to introduce some synchronisation routines under the hood which
>> > would make the XIVE hcalls longer to complete.
>> > 
>> > As this was done for H_INT_RESET, let's wrap the other hcalls in a
>> > loop catching the H_LONG_BUSY_* codes.
>> 
>> Are we sure it's safe to msleep() in all these paths?
>
> Probably not. We can have the IRQ descriptor lock. We might need to
> mdelay.
>
> There's a Kconfig option (forgot which one) that will add checks for
> attempts to sleep inside locks, you should run with that.

CONFIG_DEBUG_ATOMIC_SLEEP

cheers