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.
Paolo
