On Sat, Oct 20, 2018 at 07:41:36PM +0200, Borislav Petkov wrote:
> Dropping stable.
>
> On Sat, Oct 20, 2018 at 07:41:58AM -0700, Andi Kleen wrote:
> > From: Andi Kleen <a...@linux.intel.com>
> >
> > The Intel microcode revision space is unsigned. Inside Intel there are
> > special
> > microcodes that have the highest bit set, and they are considered to have
> > a higher revision than any microcodes that don't have this bit set.
> >
> > The function comparing the microcode revision in the Linux driver compares
> > u32 with int, which ends up being signed extended to long on 64bit
> > systems. This results in these highest bit set microcode revision not
> > loading
> > because their revision appears negative and smaller than the
> > existing microcode.
> >
> > Change the comparison to unsigned. With that the loading works
> > as expected.
> >
> > Cc: sta...@vger.kernel.org # Any supported stable
> > Signed-off-by: Andi Kleen <a...@linux.intel.com>
> > --
> > v2: White space changes.
> > ---
> > arch/x86/kernel/cpu/microcode/intel.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kernel/cpu/microcode/intel.c
> > b/arch/x86/kernel/cpu/microcode/intel.c
> > index 16936a24795c..e54d402500d3 100644
> > --- a/arch/x86/kernel/cpu/microcode/intel.c
> > +++ b/arch/x86/kernel/cpu/microcode/intel.c
> > @@ -93,7 +93,8 @@ static int find_matching_signature(void *mc, unsigned int
> > csig, int cpf)
> > /*
> > * Returns 1 if update has been found, 0 otherwise.
> > */
> > -static int has_newer_microcode(void *mc, unsigned int csig, int cpf, int
> > new_rev)
> > +static int has_newer_microcode(void *mc, unsigned int csig, int cpf,
> > + unsigned new_rev)
> > {
> > struct microcode_header_intel *mc_hdr = mc;
> >
> > --
>
> Please incorporate all review comments before sending a new version of
> your patch.
I replaced one more microcodes with microcodes revisions if that is
what you meant.
-Andi
