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

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>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b3705ae52824907085bb613cd1e16a843138e8b0..143b7ae526240395e557da13a7ba6235c6e4ad2b 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4189,7 +4189,9 @@ 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 37dd9a9d050a77d0ae33d8ec55cc3780eebb49dd..e6b4e5665d742f21acf6387ee58b67ef6b55c1ae 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -856,7 +856,7 @@ 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))