> Subject: RE: [PATCH] xen: introduce xen_vring_use_dma > > On Mon, 29 Jun 2020, Peng Fan wrote: > > > > If that is the case, how is it possible that virtio breaks on ARM > > > > using the default dma_ops? The breakage is not Xen related (except > > > > that Xen turns dma_ops on). The original message from Peng was: > > > > > > > > vring_map_one_sg -> vring_use_dma_api > > > > -> dma_map_page > > > > -> __swiotlb_map_page > > > > ->swiotlb_map_page > > > > ->__dma_map_area(phys_to_virt(dma_to_phys(dev, > > > dev_addr)), size, dir); > > > > However we are using per device dma area for rpmsg, phys_to_virt > > > > could not return a correct virtual address for virtual address in > > > > vmalloc area. Then kernel panic. > > > > > > > > I must be missing something. Maybe it is because it has to do with > RPMesg? > > > > > > I think it's an RPMesg bug, yes > > > > rpmsg bug is another issue, it should not use dma_alloc_coherent for > > reserved area, and use vmalloc_to_page. > > > > Anyway here using dma api will also trigger issue. > > Is the stack trace above for the RPMesg issue or for the Trusty issue? The stack trace you pasted is rpmsg issue. > If it is the stack trace for RPMesg, can you also post the Trusty stack trace? Or > are they indentical? There is no stack dump here. It successfully using swiotlb to do a map, but we actually no need swiotlb in domu to do the map. Thanks, Peng. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
