Re: [RESEND] Spectre-v2 (IBPB/IBRS) and SSBD fixes for 4.4.y

[Greg KH <gregkh@linuxfoundation.org>]

On Sat, Jul 14, 2018 at 02:25:43AM -0700, Srivatsa S. Bhat wrote:
> Hi Greg,
> 
> This patch series is a backport of the Spectre-v2 fixes (IBPB/IBRS)
> and patches for the Speculative Store Bypass vulnerability to 4.4.y
> (they apply cleanly on top of 4.4.140).
> 
> I used 4.9.y as my reference when backporting to 4.4.y (as I thought
> that would minimize the amount of fixing up necessary). Unfortunately
> I had to skip the KVM fixes for these vulnerabilities, as the KVM
> codebase is drastically different in 4.4 as compared to 4.9. (I tried
> my best to backport them initially, but wasn't confident that they
> were correct, so I decided to drop them from this series).
> 
> You'll notice that the initial few patches in this series include
> cleanups etc., that are non-critical to IBPB/IBRS/SSBD. Most of these
> patches are aimed at getting the cpufeature.h vs cpufeatures.h split
> into 4.4, since a lot of the subsequent patches update these headers.
> On my first attempt to backport these patches to 4.4.y, I had actually
> tried to do all the updates on the cpufeature.h file itself, but it
> started getting very cumbersome, so I resorted to backporting the
> cpufeature.h vs cpufeatures.h split and their dependencies as well. I
> think apart from these initial patches, the rest of the patchset
> doesn't have all that much noise. 

I've applied the "initial" patches to the 4.4-stable queue right now, as
those were all just "housekeeping" stuff.  I'll let others review the
rest of the series this week and see if anyone objects before throwing
them at the test-bots.

Many thanks for doing all of this work.

greg k-h