On Mon, Aug 20, 2018 at 09:52:19PM +0000, Woodhouse, David wrote: > On Mon, 2018-08-20 at 14:48 -0700, Linus Torvalds wrote: > > > > Of course, after the long (and entirely unrelated) discussion about > > the TLB flushing bug we had, I'm starting to worry about my own > > competence, and maybe I'm missing something really fundamental, and > > the XPFO patches do something else than what I think they do, or my > > "hey, let's use our Meltdown code" idea has some fundamental weakness > > that I'm missing. > > The interesting part is taking the user (and other) pages out of the > kernel's 1:1 physmap. > > It's the *kernel* we don't want being able to access those pages, > because of the multitude of unfixable cache load gadgets. I am missing why we need this since the kernel can't access (SMAP) unless we go through to the copy/to/from interface or execute any of the user pages. Is it because of the dependency on the availability of those features? Balbir Singh.
