On Mon, 10 Aug 2015, Julien Grall wrote: > Hi Stefano, > > On 10/08/15 11:50, Stefano Stabellini wrote: > > On Fri, 7 Aug 2015, Julien Grall wrote: > >> On ARM all dma-capable devices on a same platform may not be protected > >> by an IOMMU. The DMA requests have to use the BFN (i.e MFN on ARM) in > >> order to use correctly the device. > >> > >> While the DOM0 memory is allocated in a 1:1 fashion (PFN == MFN), grant > >> mapping will screw this contiguous mapping. > >> > >> When Linux is using 64KB page granularitary, the page may be split > >> accross multiple non-contiguous MFN (Xen is using 4KB page > >> granularity). Therefore a DMA request will likely fail. > >> > >> Checking that a 64KB page is using contiguous MFN is tedious. For > >> now, always says that biovec are not mergeable. > >> > >> Signed-off-by: Julien Grall <julien.gr...@citrix.com> > > > > Please fix the grammar in the subject line. > > If I made a mistake it's unlikely that I will find myself which one I made. > > Anyway, I guess you mean to replace merge by merged? I don't see any > other in the subject.
yes and page/pages: xen/biomerge: Don't allow biovec's to be merged when Linux is not using 4KB pages -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
