On Sun, May 10, 2020 at 01:18:34AM -0400, Qian Cai wrote: > It is unsafe to traverse kvm->arch.spapr_tce_tables and > stt->iommu_tables without the RCU read lock held. Also, add > cond_resched_rcu() in places with the RCU read lock held that could take > a while to finish. This mostly looks fine. The cond_resched_rcu() in kvmppc_tce_validate doesn't seem necessary (the list would rarely have more than a few dozen entries) and could be a performance problem given that TCE validation is a hot-path. Are you OK with me modifying the patch to take out that cond_resched_rcu(), or is there some reason why it's essential that it be there? Paul.
