x86/umip: Identify the STR and SLDT instructions

The STR and SLDT instructions are not emulated by the UMIP code, thus
there's no functionality in the decoder to identify them.

However, a subsequent commit will introduce a warning about the use
of all the instructions that UMIP protect/changes, not only those that
are emulated.

A first step for that is to add the ability to decode/identify them.

Plus, now that STR and SLDT are identified, we need to explicitly avoid
their emulation (i.e., not rely on successful identification). Group
together all the cases that we do not want to emulate: STR, SLDT and user
long mode processes.

Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi V. Shankar <ravi.v.shankar@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: ricardo.neri@intel.com
Link: http://lkml.kernel.org/r/1510640985-18412-4-git-send-email-ricardo.neri-calderon@linux.intel.com


[ Rewrote the changelog, fixed ugly col80 artifact. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>