Re: [PATCH v3 01/13] x86/retpoline: Add initial retpoline support

From: Josh Poimboeuf
Date: Fri Jan 05 2018 - 12:08:19 EST


On Fri, Jan 05, 2018 at 05:45:06PM +0100, Borislav Petkov wrote:
> On Fri, Jan 05, 2018 at 04:41:46PM +0000, Woodhouse, David wrote:
> > Nope, alternatives are broken. Only a jmp as the *first* opcode of
> > altinstr gets handled by recompute_jump(), while any subsequent insn is
> > just copied untouched.
>
> Not broken - simply no one needed it until now. I'm looking into it.
> Looks like the insn decoder might come in handy finally.
>
> :-)

I seem to recall that we also discussed the need for this for converting
pvops to use alternatives, though the "why" is eluding me at the moment.

--
Josh