Re: [PATCH v7 20/26] x86/cpufeature: Add User-Mode Instruction Prevention definitions

Ricardo Neri
2017-05-11T03:23:22Z

On Sat, 2017-05-06 at 11:04 +0200, Paolo Bonzini wrote:
>
>
> On 05/05/2017 20:17, Ricardo Neri wrote:
> > User-Mode Instruction Prevention is a security feature present in
> new
> > Intel processors that, when set, prevents the execution of a subset
> of
> > instructions if such instructions are executed in user mode (CPL >
> 0).
> > Attempting to execute such instructions causes a general protection
> > exception.
> >
> > The subset of instructions comprises:
> >
> > * SGDT - Store Global Descriptor Table
> > * SIDT - Store Interrupt Descriptor Table
> > * SLDT - Store Local Descriptor Table
> > * SMSW - Store Machine Status Word
> > * STR - Store Task Register
> >
> > This feature is also added to the list of disabled-features to allow
> > a cleaner handling of build-time configuration.
> >
> > Cc: Andy Lutomirski <luto@kernel.org>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: H. Peter Anvin <hpa@zytor.com>
> > Cc: Borislav Petkov <bp@suse.de>
> > Cc: Brian Gerst <brgerst@gmail.com>
> > Cc: Chen Yucong <slaoub@gmail.com>
> > Cc: Chris Metcalf <cmetcalf@mellanox.com>
> > Cc: Dave Hansen <dave.hansen@linux.intel.com>
> > Cc: Fenghua Yu <fenghua.yu@intel.com>
> > Cc: Huang Rui <ray.huang@amd.com>
> > Cc: Jiri Slaby <jslaby@suse.cz>
> > Cc: Jonathan Corbet <corbet@lwn.net>
> > Cc: Michael S. Tsirkin <mst@redhat.com>
> > Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Ravi V. Shankar <ravi.v.shankar@intel.com>
> > Cc: Shuah Khan <shuah@kernel.org>
> > Cc: Vlastimil Babka <vbabka@suse.cz>
> > Cc: Tony Luck <tony.luck@intel.com>
> > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > Cc: Liang Z. Li <liang.z.li@intel.com>
> > Cc: Alexandre Julliard <julliard@winehq.org>
> > Cc: Stas Sergeev <stsp@list.ru>
> > Cc: x86@kernel.org
> > Cc: linux-msdos@vger.kernel.org
> >
> > Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
>
> Would it be possible to have this patch in a topic branch for KVM's
> consumption?
>
I have put a branch here with this single patch:

https://github.com/ricardon/tip.git rneri/umip_for_kvm

This is based on Linux v4.11. Please let me know if this works for your
or you'd prefer it to be based on a different branch/commit/repo.

Thanks and BR,
Ricardo