commit 3afb1121 upstream.

These have roughly the same purpose as the SMRR, which we do not need
to implement in KVM.  However, Linux accesses MSR_K8_TSEG_ADDR at
boot, which causes problems when running a Xen dom0 under KVM.
Just return 0, meaning that processor protection of SMRAM is not
in effect.
Reported-by: M A Young <m.a.young@durham.ac.uk>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[ luis: backported to 3.16:
  - file rename: arch/x86/include/asm/msr-index.h ->
    arch/x86/include/uapi/asm/msr-index.h
  - adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>