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 b3705ae..143b7ae 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 37dd9a9..e6b4e56 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))