On Thu, Jan 30, 2020 at 11:23:02PM +0000, Rick Macklem wrote: > Hi, > > The current code for KERN_TLS uses PHYS_TO_DMAP() > to access unmapped external pages on m_ext.ext_pgs > mbufs. > I also need to do this to implement RPC-over-TLS. > > The problem is that some arches, like i386, don't > support PHYS_TO_DMAP(). > > Since it appears that there will be at most 4 pages on > one of these mbufs, my thinking was... > - Acquire four pages of kva from the kernel_map during > booting. > - Then just use pmap_qenter() to fill in the physical page > mappings for long enough to copy the data. > > Does this sound reasonable? > Is there a better way?
Use sfbufs, they should work on all arches. In essence, they provide MI interface to DMAP where possible. I do not remember did I bumped the limit for i386 after 4/4 went in. There is currently no limits for sfbufs use per subsystem, but I think it is not very likely to cause too much troubles. Main rule is to not sleep waiting for more sfbufs if you already own one.. _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
