On Monday 19 May 2008 12:01:27 FUJITA Tomonori wrote:
I think what's more useful is a chain with a properly defined order or
hierarchy (based on what Muli suggested last time we discussed this
http://lkml.org/lkml/2007/11/12/44 )
The suggested order was (in calling order):
pvdma->hardare->nommu/swiotlb
The discussion in the thread pointed to above has details as to why.
OK; this sounds helpful. the hook can make a hypercall and confirm with the
host kernel if the device in question is an assigned physical device. If yes,
we replace the dma_ops. Though, the original intent of having stackable ops
is that we might want to go through the swiotlb in the guest even for an
assigned device if the guest dma addresses are not in the addressable range
of the guest chipset.
From what we've discussed so far, it looks like stackable dma ops will
definitely be needed. Does this patchset provide something that stacking
won't?
Amit.
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