On Wed, Oct 22, 2014 at 04:17:29PM +0200, Joerg Roedel wrote: > Hi Frank, > > On Tue, Oct 21, 2014 at 01:57:25PM +0200, Frank Blaschka wrote: > > Add a basic iommu for the s390 platform. The code is pretty simple > > since on s390 each PCI device has its own virtual io address space > > starting at the same vio address. > > Are there any limitations on IOVA address space for the devices or can > be really any system physical address mapped starting from 0 to 2^64? > Hi Joerg, Basically there are no limitations. Depending on the s390 maschine generation a device starts its IOVA at a specific address (announced by the HW). But as I already told each device starts at the same address. I think this prevents having multiple devices on the same IOMMU domain. > > For this a domain could hold only one pci device. > > This bothers me, as it is not compatible with the IOMMU-API. I looked a > little bit into how the mappings are created, and it seems there is a > per-device dma_table. > yes, you are absolutely right. There is a per-device dma_table. There is no general IOMMU device but each pci device has its own IOMMU translation capability. > Is there any reason a dma_table can't be per IOMMU domain and assigned > to multiple devices at the same time? Is there a possibility the IOMMU domain can support e.g. something like VIOA 0x10000 -> pci device 1 VIOA 0x10000 -> pci device 2 > > Otherwise the code looks quite simple and straight forward. > Thx for your review and help Frank > > Joerg > > -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
