On 17/08/19 11:32, Peter Xu wrote: > The previous has_coalesced_range counter has a problem in that it only > works for additions of coalesced mmio ranges but not deletions. The > reason is that has_coalesced_range information can be lost when the > FlatView updates the topology again when the updated region is not > covering the coalesced regions. When that happens, due to > flatrange_equal() is not checking against has_coalesced_range, the new > FlatRange will be seen as the same one as the old and the new > instance (whose has_coalesced_range will be zero) will replace the old > instance (whose has_coalesced_range _could_ be non-zero). > > To fix it, we don't cache has_coalesced_range at all in the FlatRange. > Instead we introduce two flags to make sure the coalesced_io_{add|del} > will only be called once for every FlatRange instance. This will even > work if another FlatRange replaces current one.
It's still a bit ugly that coalesced_mmio_add_done ends up not being set on the new (but equal) FlatRange. Would something like this work too? diff --git a/memory.c b/memory.c index edd0c13..fc91f06 100644 --- a/memory.c +++ b/memory.c @@ -939,6 +939,7 @@ static void address_space_update_topology_pass(AddressSpace *as, /* In both and unchanged (except logging may have changed) */ if (adding) { + frnew->has_coalesced_range = frold->has_coalesced_range; MEMORY_LISTENER_UPDATE_REGION(frnew, as, Forward, region_nop); if (frnew->dirty_log_mask & ~frold->dirty_log_mask) { MEMORY_LISTENER_UPDATE_REGION(frnew, as, Forward, log_start, Thanks, Paolo > Without this patch, MemoryListener.coalesced_io_del is hardly being > called due to has_coalesced_range will be mostly zero in > flat_range_coalesced_io_del() when topologies frequently change for > the "memory" address space.