Re: [PATCH v2] KVM: x86: use array_index_nospec with indices that come from guest

[Sean Christopherson <seanjc@google.com>]

On Mon, Aug 11, 2025, Greg Kroah-Hartman wrote:
> On Thu, Jul 24, 2025 at 12:04:15PM -0700, Sean Christopherson wrote:
> > On Thu, Jul 24, 2025, Greg Kroah-Hartman wrote:
> > > On Thu, Jul 24, 2025 at 04:22:27PM +0200, Thijs Raymakers wrote:
> > > > min and dest_id are guest-controlled indices. Using array_index_nospec()
> > > > after the bounds checks clamps these values to mitigate speculative execution
> > > > side-channels.
> > > > 
> > > > Signed-off-by: Thijs Raymakers <thijs@raymakers.nl>
> > > > Cc: stable <stable@kernel.org>
> > > > Cc: Sean Christopherson <seanjc@google.com>
> > > > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > 
> > > Nit, you shouldn't have added my signed off on a new version, but that's
> > > ok, I'm fine with it.
> > 
> > Want me to keep your SoB when applying, or drop it?
> > 
> > > > ---
> > > >  arch/x86/kvm/lapic.c | 2 ++
> > > >  arch/x86/kvm/x86.c   | 7 +++++--
> > > >  2 files changed, 7 insertions(+), 2 deletions(-)
> > > 
> > > You also forgot to say what changed down here.
> > > 
> > > Don't know how strict the KVM maintainers are, I know I require these
> > > things fixed up...
> > 
> > I require the same things, but I also don't mind doing fixup when applying if
> > that's the path of least resistance (and it's not a recurring problem).
> > 
> > I also strongly dislike using In-Reply-To for new versions, as it tends to confuse
> > b4, and often confuses me as well.
> > 
> > But for this, I don't see any reason to send a v3.
> 
> Any status on this?  I don't see it in linux-next at all, nor in
> 6.17-rc1

I'll get it applied and sent along to Paolo/Linus this week.