On Wed, Mar 10, 2021 at 10:15:01AM +0100, Christoph Hellwig wrote: > On Thu, Mar 04, 2021 at 03:25:27PM +0000, Robin Murphy wrote: > > On 2021-03-01 08:42, Christoph Hellwig wrote: > >> Use explicit methods for setting and querying the information instead. > > > > Now that everyone's using iommu-dma, is there any point in bouncing this > > through the drivers at all? Seems like it would make more sense for the x86 > > drivers to reflect their private options back to iommu_dma_strict (and > > allow Intel's caching mode to override it as well), then have > > iommu_dma_init_domain just test !iommu_dma_strict && > > domain->ops->flush_iotlb_all. > > Hmm. I looked at this, and kill off ->dma_enable_flush_queue for > the ARM drivers and just looking at iommu_dma_strict seems like a > very clear win. > > OTOH x86 is a little more complicated. AMD and intel defaul to lazy > mode, so we'd have to change the global iommu_dma_strict if they are > initialized. Also Intel has not only a "static" option to disable > lazy mode, but also a "dynamic" one where it iterates structure. So > I think on the get side we're stuck with the method, but it still > simplifies the whole thing. Actually... Just mirroring the iommu_dma_strict value into struct iommu_domain should solve all of that with very little boilerplate code.
