[PATCH 1/2] i386: Generate lfence with load/indirect branch/ret [CVE-2020-0551]

[Hongtao Liu]

On Fri, Apr 24, 2020 at 2:01 PM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 24.04.2020 07:30, Hongtao Liu wrote:
> > Change to
> >
> > +      /* lret or iret.  */
> > +      bfd_boolean lret = (i.tm.base_opcode | 0x5) == 0xcf;
> > +      bfd_boolean has_rexw = i.prefix[REX_PREFIX] & REX_W;
> > +      char prefix = 0x0;
> > +      /* Default operand size for far return is 32 bits,
> > +         64 bits for near return.  */
> > +      /* Near ret ingore operand size override under CPU64.  */
> > +      if ((!lret && flag_code == CODE_64BIT) || has_rexw)
> > +        prefix = 0x48;
> >        else
> > +        prefix = i.prefix[DATA_PREFIX] ? 0x66 : 0x0;
>
> One minor remark on this one - I'd suggest to either omit the
> initializer for prefix, or make the last two lines
>
>       else if (i.prefix[DATA_PREFIX])
>         prefix = 0x66;
>
> as there's no point assigning 0 twice.
>

I'll do this change.

> > Update total patch:
>
> Looks okay to me now, thanks.
>
> Jan

Thanks for you review and patience, I'll wait for H.J's approval and
submit my patch.

-- 
BR,
Hongtao