Re: [PATCH 17/30] x86, kaiser: map debug IDT tables

[Andy Lutomirski]

On Fri, Nov 10, 2017 at 11:31 AM, Dave Hansen
<dave.hansen@xxxxxxxxxxxxxxx> wrote:
>
> From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
>
> The IDT is another structure which the CPU references via a
> virtual address.  It also obviously needs these to handle an
> interrupt in userspace, so these need to be mapped into the user
> copy of the page tables.

Why would the debug IDT ever be used in user mode?  IIRC it's a total
turd related to avoiding crap nesting inside NMI.  Or am I wrong?

If it *is* used in user mode, then we have a bug and it should be in
the IDT to avoid address leaks just like the normal IDT.

--Andy