On Saturday 29 March 2008, Anthony Liguori wrote: > This patch introduces a PCI DMA API and some generic code to support other > DMA APIs. Two types are introduced: PhysIOVector and IOVector. A DMA API > maps a PhysIOVector, which is composed of target_phys_addr_t, into an > IOVector, which is composed of void *.
Devices should not be using IOVector. They should either use the DMA copy routines to copy from a PhysIOVector into a local buffer, or they should pass a PhysIOVector to a block/network read/write routine. The DMA API should allow devices to be agnostic about how DMA is implemented. They should not be trying to manually implement zero copy. > This enables zero-copy IO to be preformed without introducing assumptions > of phys_ram_base. This API is at the PCI device level to enable support of > per-device IOMMU remapping. By my reading it *requires* bridges be zero-copy. For big-endian targets we need to ability to byteswap accesses. Some description (in the form of source comments) of how it's meant to be used would also be helpful. Paul ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
