On Thu, Oct 25, 2018 at 11:56:02AM -0700, Joe Jin wrote: > I just discussed this patch with Boris in private, his opinions(Boris, > please correct me if any misunderstood) are: > > 1. With/without the check, both are incorrect, he thought we need to > prevented unalloc'd free at here. > 2. On freeing, if upper layer already checked the memory was DMA-able, > the checking at here does not make sense, we can remove all checks. > 3. xen_create_contiguous_region() and xen_destroy_contiguous_region() > to come in pairs. > > For #1 and #3, I think we need something associate it, like a list, on > allocating, add addr to it, on freeing, check if in the list.
Is there any way to figure out based on an address if the exchange operation happened? > For #2, I'm was not found anywhere validated the address on > dma_free_coherent() callpath, not just xen-swiotlb. At least for simple direct mappings there is no easy way to verify that without keeping a list, and for some of the ops that do vmap like operations we have basic santiy checks, but nothing that really catches a wrong free. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
