Hey, On Wed, Feb 14, 2024 at 04:47:49PM +0000, Marc Zyngier wrote: > I'd like to propose an alternative approach here. I've always hated > this "copy a bunch of INTIDs" thing, Agree. > and the only purpose of this > silly counter is to dimension the resulting array. Well, we also use it to trivially print the number of LPIs for a particular vgic in the debug interface. > Could we instead rely on an xarray marking a bunch of entries (the > ones we want to 'copy'), and get the reader to clear these marks once > done? I think that'd work. I'm trying to convince myself we don't have bugs lurking in some of the existing usage of vgic_copy_lpi_list()... > 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! :) 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. -- Thanks, Oliver
