ACK/Cmnt: [SRU Bionic/Focal/Impish 0/5] Spectre-BHB followups

[Thadeu Lima de Souza Cascardo]

On Tue, Apr 05, 2022 at 10:22:08AM +0200, Stefan Bader wrote:
> On 04.04.22 22:16, Thadeu Lima de Souza Cascardo wrote:
> > [Impact]
> > The LFENCE mitigation was found out not to be sufficient on AMD systems. And
> > unprivileged eBPF was considered in the mitigation status for Spectre v2.
> > 
> > [Fixes]
> > "x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation
> > reporting" need to be backported from close upstream stable branches.
> > 
> > [Potential regression]
> > Mitigations may not be applied correctly and changing unprivileged eBPF
> > setting may cause surprising effects. Mitigations may be reported incorrectly
> > or incompletely.
> > Josh Poimboeuf (3):
> >    x86/speculation: Include unprivileged eBPF status in Spectre v2
> >      mitigation reporting
> >    x86/speculation: Warn about Spectre v2 LFENCE mitigation
> >    x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT
> > 
> > Kim Phillips (2):
> >    x86/speculation: Use generic retpoline by default on AMD
> >    x86/speculation: Update link to AMD speculation whitepaper
> > 
> >   Documentation/admin-guide/hw-vuln/spectre.rst |  6 +-
> >   arch/x86/kernel/cpu/bugs.c                    | 71 +++++++++++++++----
> >   include/linux/bpf.h                           | 11 +++
> >   kernel/sysctl.c                               |  8 +++
> >   4 files changed, 79 insertions(+), 17 deletions(-)
> > 
> 
> The s-o-b for Focal and Bionic sometimes has cherry picked from some
> upstream stable and then looks like from upstream directly. Just to double
> check that this is correct. Generally
> 
> Acked-by: Stefan Bader <stefan.bader at canonical.com>

Double checking here, it seems only the first patch for bionic is missing the
provenance, which would also be linux-4.19.y.

The others have been clean cherry-picks, though I noticed that for Impish, I
ended up using the 5.15 backports that were used for Jammy. Aside from the
first patch, which required the backport, all the other ones are clean
cherry-picks as well.

Cascardo.