>>> On 19.11.14 at 17:02, <david.vra...@citrix.com> wrote: > On a Xen PV guest the DMA addresses and physical addresses are not 1:1 > (such as Xen PV guests) and the generic dma_get_required_mask() does > not return the correct mask (since it uses max_pfn). > > Some device drivers (such as mptsas, mpt2sas) use > dma_get_required_mask() to set the device's DMA mask to allow them to > use only 32-bit DMA addresses in hardware structures. This results in > unnecessary use of the SWIOTLB if DMA addresses are more than 32-bits, > impacting performance significantly. > > Provide a get_required_mask op that uses the maximum MFN to calculate > the DMA mask. > > Signed-off-by: David Vrabel <david.vra...@citrix.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com> _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
