Il 01/05/2013 07:06, David Gibson ha scritto: >>> + + /* FIXME: inherit memory region from bus creator */ + >>> memory_region_init_alias(mr, "iommu-nop", get_system_memory(), >>> 0, INT64_MAX); + return mr; > I don't see the reason for creating a new alias for each PCI > device. Can't pci_dev->iommu just point directly to > get_system_memory() in the normal case? > > In addition to creating additional objects, having these aliases > makes it much les obvious how to tell if two PCI devices share an > IOMMU address space. We have to be able to determine that for > VFIO, since devices which share an address space in the host > clearly can't be assigned to different address spaces in the > guest.
Right, the alias that is needed to enable/disable bus-mastering is created already below, so pci_dev->iommu can be shared (as it is in the spapr case). Paolo
