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

commit 5ecad245de2ae23dc4e2dbece92f8ccfbaed2fa7 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: a0c0feb57992 ("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>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index aab02ea2d2cb22c4dea0de60ca4edad408305320..342d9ddf35c3a8ccea33af4602b5bf90fefd3658 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4580,7 +4580,7 @@ __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);