[kernel-hardening] Re: [Xen-devel] [PATCH v5 2/3] x86: Remap GDT tables in the Fixmap section

Thomas Garnier
2017-03-13T19:24:21Z

On Mon, Mar 13, 2017 at 11:32 AM, Boris Ostrovsky
<boris.ostrovsky@oracle.com> wrote:
> There are a couple of problems for Xen PV guests that need to be addressed:
> 1. Xen's set_fixmap op needs non-default handling for
> FIX_GDT_REMAP_BEGIN range
> 2. GDT remapping for PV guests needs to be RO for both 64 and 32-bit guests.
>
> I don't know how you prefer to deal with (2), patch below is one
> suggestion. With it all my boot tests (Xen and bare-metal) passed.
>

Good suggestion, I think I will use most of it. Thanks!

> One problem with applying it directly is that kernel becomes
> not-bisectable (Xen-wise) between patches 2 and 3 so perhaps you might
> pull some of the changes from patch 3 to patch 2.
>

Yes that make sense, I will have to add the global variable on patch 2
and rebase 3 correctly.

--
Thomas