KVM: x86: bit 8 of non-leaf PDPEs is not reserved

BugLink: https://bugs.launchpad.net/bugs/1888690

commit 5ecad245 upstream.

Bit 8 would be the "global" bit, which does not quite make sense for non-leaf
page table entries.  Intel ignores it; AMD ignores it in PDEs and PDPEs, but
reserves it in PML4Es.

Probably, earlier versions of the AMD manual documented it as reserved in PDPEs
as well, and that behavior made it into KVM as well as kvm-unit-tests; fix it.

Cc: stable@vger.kernel.org
Reported-by: Nadav Amit <namit@vmware.com>
Fixes: a0c0feb5 ("KVM: x86: reserve bit 8 of non-leaf PDPEs and PML4Es in 64-bit mode on AMD", 2014-09-03)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

arch/x86/kvm/mmu.c

@@ -3767,7 +3767,7 @@ __reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
 			nonleaf_bit8_rsvd | rsvd_bits(7, 7) |
 			rsvd_bits(maxphyaddr, 51);
 		rsvd_check->rsvd_bits_mask[0][2] = exb_bit_rsvd |
-			nonleaf_bit8_rsvd | gbpages_bit_rsvd |
+			gbpages_bit_rsvd |
 			rsvd_bits(maxphyaddr, 51);
 		rsvd_check->rsvd_bits_mask[0][1] = exb_bit_rsvd |
 			rsvd_bits(maxphyaddr, 51);