[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] Retry 3: Use i386 swiotlb code in lib/swiotlb-xen.c [2/2]
On 27/2/07 20:49, "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx> wrote: > You can either use the vaddr check from original lib/swiotlb.c *or* you can > pass the dma_handle to in_swiotlb_aperture(). You cannot pass a vaddr to > in_swiotlb_aperture(): it makes no sense! > > Actually I think the dma_alloc_coherent() you've hauled in from native > x86/64 code won't even work on Xen as it is. The dma_alloc_pages() function > it uses first won't guarantee to return contiguous memory on Xen, but that > is implicitly assumed by the caller. Perhaps it would be best to focus on just the changes required to meet your main objective, which (I think?) is to move Xen x86/64 over to dma_ops so that you can conveniently slide the AMD GART implementation in place of the swiotlb. If this is the case, relocating swiotlb.c to lib/swiotlb-xen.c and doing a halfway merge with lib/swiotlb.c is not really on the critical path. Moreover, Jan has some patches pending for mainline Linux which will change things around in that area anyway if they get accepted. Now is probably not the time to churn the swiotlb.c code. Instead can you not just define a swiotlb-based dma_mapping_ops structure in a suitable arch/x86_64 file (e.g., pci-swiotlb-xen.c would be an obvious place) and then work on moving us towards using dma_ops hooks for all the dma-mapping operations. You could do this latter step piecemeal across a number of patches if you like (i.e., so that intermediate steps some dma operations are using the dma_ops hooks while others are still statically falling back to calling into swiotlb code directly). Probably you'd start off taking a copy of i386/kernel/pci-dma-xen.c into x86_64, and then progressively pull in dma_ops logic from x86_64/kernel/pci_dma.c. At the same time you'd be progressively reintroducing dma_ops usage into mach-xen/asm/dma-mapping.h as well. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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