On Wed, Apr 27, 2016 at 07:31:43AM -0700, Andy Lutomirski wrote: > On Wed, Apr 27, 2016 at 7:23 AM, Joerg Roedel <j...@8bytes.org> 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
Meaning virtio or assigned devices? For virtio - it's way too late since these are working configurations. For assigned devices - they don't work on x86 so it doesn't have to be disabled, it's safe to ignore. -- MST _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
