Re: [PATCH 6.18] x86/bugs: Adapt SRSO mitigation to Zen6

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Nov 04, 2026 at 09:08:29PM +0000, Borislav Petkov wrote:
> On November 4, 2026 5:58:23 PM UTC, Greg KH <gregkh@linuxfoundation.org> wrote:
> >On Tue, Nov 03, 2026 at 10:21:43AM -0800, S Shaiju (AMD) wrote:
> >> From: "Borislav Petkov (AMD)" <bp@alien8.de>
> >> 
> >> commit ae1d2082d93bc04604dc08e9b7f9cdba5e0c28e6 upstream.
> >> 
> >> Zen6 has BTB protection which isolates the different contexts
> >> (user/kernel, guest/host) from one another. This makes the SafeRET
> >> mitigation there unnecessary leaving the user/user and guest/guest
> >> attack vectors open, whose protection is handled by the Spectre v2
> >> mitigation setting to do IBPB on a context switch.
> >> 
> >> Detect that setting and report it with a new mitigation string.
> >> 
> >> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
> >> Link: https://patch.msgid.link/20260822013231.1109255-1-bp@kernel.org
> >> Signed-off-by: S Shaiju (AMD) <sshaiju.lkml@gmail.com>
> >> ---
> >>  arch/x86/include/asm/cpufeatures.h |  1 +
> >>  arch/x86/kernel/cpu/bugs.c         | 18 ++++++++++++++++--
> >>  arch/x86/kernel/cpu/scattered.c    |  1 +
> >>  3 files changed, 18 insertions(+), 2 deletions(-)
> >
> >You forgot to mention this needs to go to 7.3.y too.
> >
> >Now queued up, thanks.
> >
> >greg k-h
> 
> Ah, thanks. You guys are opening and closing non-LTS branches waay to fast for me :-)

7.3 will be LTS :)