Re: [RFC][PATCH] objtool,x86_64,paravirt: Add pv_ops[] support

[Andy Lutomirski]

On Mon, Aug 3, 2020 at 7:33 AM <peterz@xxxxxxxxxxxxx> wrote:
>
>
> Thomas wanted paramuck vs noinstr, here goes. Very rough, very nasty,
> mostly works.
>
> It requires call sites are the normal indirect call, and not mangled
> retpoison (slow_down_io() had those), it also requires pv_ops[]
> assignments are single instructions and not laundered through some
> pointless intermediate helper (hyperv).
>
> It doesn't warn when you get any of that wrong.
>
> But if you have it all lined up right, it will warn about noinstr
> violations due to paramuck:

I certainly agree that pv_ops is mucky, but could you expound on
precisely what this patch actually does?  On a very quick
read-through, I'm guessing you're complaining about any call to pv_ops
in a noinstr section?  But maybe this is only calls to pv_ops that
aren't themselves noinstr?