On 05/23/2014 09:28 PM, Alexander Graf wrote: > > On 23.05.14 06:59, Alexey Kardashevskiy wrote: >> From: David Gibson <da...@gibson.dropbear.id.au> >> >> The only model so far supported for VFIO passthrough devices is the model >> usually used on x86, where all of the guest's RAM is mapped into the >> (host) IOMMU and there is no IOMMU visible in the guest. >> >> This patch begins to relax this model, introducing the notion of a >> VFIOAddressSpace. This represents a logical DMA address space which will >> be visible to one or more VFIO devices by appropriate mapping in the (host) >> IOMMU. Thus the currently global list of containers becomes local to >> a VFIOAddressSpace, and we verify that we don't attempt to add a VFIO >> group to multiple address spaces. >> >> For now, only one VFIOAddressSpace is created and used, corresponding to >> main system memory, that will change in future patches. >> >> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au> >> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> > > Don't we already have a DMA address space in the PCI bus? We could just use > that one instead, no?
I do not know about x86, but for spapr that VFIOAddressSpace is nothing but wrapper around an AddressSpace from the SPAPR PHB. -- Alexey
