On Wed, Apr 27, 2016 at 7:23 AM, Joerg Roedel <joro@xxxxxxxxxx> wrote: > On Wed, Apr 27, 2016 at 04:37:04PM +0300, Michael S. Tsirkin wrote: >> One correction: it's a feature of the device in the system. >> There could be a mix of devices bypassing and not >> bypassing the IOMMU. > > No, it really is not. A device can't chose to bypass the IOMMU. But the > IOMMU can chose to let the device bypass. So any fix here belongs > into the platform/iommu code too and not into some driver. > >> Sounds good. And a way to detect appropriate devices could >> be by looking at the feature flag, perhaps? > > Again, no! The way to detect that is to look into the iommu description > structures provided by the firmware. They provide everything necessary > to tell the iommu code which devices are not translated. > Except on PPC and SPARC. As far as I know, those are the only problematic platforms. Is it too late to *disable* QEMU's q35-iommu thingy until it can be fixed to report correct data in the DMAR tables? --Andy _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
