Messages in this thread | | | Date | Wed, 14 Feb 2024 23:01:04 +0000 | From | Oliver Upton <> | Subject | Re: [PATCH v2 07/23] KVM: arm64: vgic: Use atomics to count LPIs |
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On Wed, Feb 14, 2024 at 08:01:19PM +0000, Marc Zyngier wrote: > > > Of course, we only have 3 marks, so that's a bit restrictive from a > > > concurrency perspective, but since most callers hold a lock, it should > > > be OK. > > > > They all hold *a* lock, but maybe not the same one! :) > > Indeed. But as long as there isn't more than 3 locks (and that the > xarray is OK being concurrently updated with marks), we're good!
Oh, you mean to give each existing caller their own mark?
> > Maybe we should serialize the use of markers on the LPI list on the > > config_lock. A slight misuse, but we need a mutex since we're poking at > > guest memory. Then we can go through the whole N-dimensional locking > > puzzle and convince ourselves it is still correct. > > Maybe. This thing is already seeing so many abuses that one more may > not matter much. Need to see how it fits in the whole hierarchy of > GIC-related locks...
It doesn't work. We have it that the config_lock needs to be taken outside the its_lock.
Too many damn locks!
-- Thanks, Oliver
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