On Fri, 19 Mar 2021, Konrad Rzeszutek Wilk wrote: > On Fri, Mar 19, 2021 at 02:07:31PM +0100, Christoph Hellwig wrote: > > On Thu, Mar 18, 2021 at 09:03:33PM -0700, Florian Fainelli wrote: > > > #ifdef CONFIG_ARM_LPAE > > > + if (swiotlb_force == SWIOTLB_FORCE || > > > + max_pfn > arm_dma_pfn_limit) > > > > Does arm_dma_pfn_limit do the right thing even with the weirdest > > remapping ranges? Maybe a commen here would be useful. > > > > > + swiotlb_init(1); > > > + else > > > + swiotlb_force = SWIOTLB_NO_FORCE; > > > > Konrad: what do you think of setting swiotlb_force to SWIOTLB_NO_FORCE > > and only switching it to SWIOTLB_NORMAL when swiotlb_init* is called? > > That kind makes more sense than forcing the callers to do it. > > > > While we're at it, I think swiotlb_force should probably be renamed to > > swiotlb_mode or somethng like that. > > swiotlb_mode sounds good. > > Also it got me thinking - ARM on Xen at some point was a bit strange, so not > sure how > the logic works here, Stefano?
There is nothing strange in regards to swiotlb_force. swiotlb_force is only used in swiotlb-xen map_page to figure out whether: - we actually have to use the swiotlb bounce buffer (this is the swiotlb_xen == SWIOTLB_FORCE case) - or we can use the provided page directly for dma if other conditions are met (dma_capable, !range_straddles_page_boundary, ...) I don't think that switching to "swiotlb_mode" would cause any issues. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu