[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Re: [PATCH 18 of 38] x86: unify pci iommu setup and allow swiotlb to compile for 32 bit
On Mon, 2008-11-17 at 12:48 +0900, FUJITA Tomonori wrote: > On Thu, 13 Nov 2008 11:10:16 -0800 > Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote: > > > swiotlb on 32 bit will be used by Xen domain 0 support. > > If you want swiotlb on 32 bit, you need more modifications, I think. Possibly. It currently "Works For Me(tm)", but I should check it over. > For example, the following code assumes that the mask needs to be > 64 bits. The use of unsigned long for the mask is throughout the API and not simply limited to swiotlb.c. All the callers of dma_set_seg_boundary (PCI and SCSI subsys it seems) do not use a value >4G anywhere I can see. Presumably if something was we would see "warning: overflow in implicit constant conversion" somewhere along the line. If no value is set then the default is 0xffffffff which is safe on 32 bit. I suspect that even with PAE addresses above 4G aren't seen very often due to pre-existing subsystem specific bounce buffers or other existing limitations (like network buffers being in lowmem). Perhaps dma_addr_t should be used though? Ian. > > static void * > map_single(struct device *hwdev, char *buffer, size_t size, int dir) > { > unsigned long flags; > char *dma_addr; > unsigned int nslots, stride, index, wrap; > int i; > unsigned long start_dma_addr; > unsigned long mask; > unsigned long offset_slots; > unsigned long max_slots; > > mask = dma_get_seg_boundary(hwdev); > start_dma_addr = virt_to_bus(io_tlb_start) & mask; > > offset_slots = ALIGN(start_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; > max_slots = mask + 1 > ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT > : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT); > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |