KVM: X86: Fix reserved bits check for MOV to CR3

BugLink: http://bugs.launchpad.net/bugs/1790188
commit a780a3ea628268b2ad0ed43d7f28d90db0ff18be upstream.

MSB of CR3 is a reserved bit if the PCIDE bit is not set in CR4.
It should be checked when PCIDE bit is not set, however commit
'd1cd3ce900441 ("KVM: MMU: check guest CR3 reserved bits based on
its physical address width")' removes the bit 63 checking
unconditionally. This patch fixes it by checking bit 63 of CR3
when PCIDE bit is not set in CR4.

Fixes: d1cd3ce900441 (KVM: MMU: check guest CR3 reserved bits based on its physical address width)
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Reviewed-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
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: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index ebdfaa576261a43411561011c0c668b6059a1b24..ffdd1612d31017bee722ccf865a638c9cd350e40 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4147,7 +4147,9 @@ static int check_cr_write(struct x86_emulate_ctxt *ctxt)
                                maxphyaddr = eax & 0xff;
                        else
                                maxphyaddr = 36;
-                       rsvd = rsvd_bits(maxphyaddr, 62);
+                       rsvd = rsvd_bits(maxphyaddr, 63);
+                       if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PCIDE)
+                               rsvd &= ~CR3_PCID_INVD;
                }
 
                if (new_val & rsvd)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 707e82fb4d41d0fc64fd7b2e4cf297bd25f011e3..cf358809314893769e74100952889dbb51d0d1e1 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -843,7 +843,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
        }
 
        if (is_long_mode(vcpu) &&
-           (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 62)))
+           (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63)))
                return 1;
        else if (is_pae(vcpu) && is_paging(vcpu) &&
                   !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))