On Wed, Apr 24, 2013 at 02:34:21PM +0200, Paolo Bonzini wrote: > Il 24/04/2013 14:01, David Gibson ha scritto: > > So while its true that the DMAContext handling needs to be better > > integrated with the MemoryRegion and AddressSpace handling, that commit > > wasn't actually a step in the right direction for it. Since then, the > > DMAContext has been extended so it can backend onto an AddressSpace, and > > thereby, a MemoryRegion. Effectively a DMAContext is now an AddressSpace > > with iommu translation handling on top. > > > > Therefore, this patch essentially reverts the earlier commit, making all > > PCI devices by default shared the global dma_context_memory which backs > > onto main system memory. Those cases which need to set up different DMA > > address spaces for each PCI device should supply a suitable dma_context_fn > > in the bus to correctly assign / create suitable DMAContext structures. > > I think this will be handled correctly when I submit IOMMU AddressSpace > patches (next week or so). The structure will be > > PCI device 1 PCI device 2 > --------------------------------------------------------------- > AddressSpace 1 AddressSpace 2 > | | > | (enable/disable) | (enable/disable) > '-------------------. .----------------' > v v > IOMMU AddressSpace > | > | (translation) > v > system memory > > VFIO will be able to access the IOMMU AddressSpace simply via > pci_dev->iommu, and that field will be ==-identical for different PCI > devices.
Hrm, ok. Still seems excessively complicated, but as long as there's
a way to get from the pci device to the common address space, I can
work with that.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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