On Wed, 2017-07-26 at 11:50 +0200, Joerg Roedel wrote: > > 3. Create IOMMU_DOMAIN_UNMANAGED IOMMU domains for PPC64/powernv IOMMU > > groups and only define capable() hook to report IOMMU_CAP_INTR_REMAP; > > others already use these IOMMU domains. VFIO-PCI's mmap() hook could then > > check the capability via iommu_capable(bus). The problems is as Robin said: > > "iommu_capable() is a fundamentally broken and unworkable interface > > anyway"; however it is still not clear to me why it is unworkable in this > > particular case of isolation checking. > > That one is wrong, IRQ remapping is not a property of a domain. A domain > is an abstraction for a device address space. Attaching IRQ information > there is just wrong. Except it somewhat is ... an MSI is a store in the device address space, the way MSIs are handled and/or filtered can be considered a property of the domain. In our case, it's the exact same piece of HW that defines domains and which MSIs they are allowed to generate. Cheers, Ben.
