KVM: nVMX: add missing consistency checks for CR0 and CR4

commit 112e66017bff7f2837030f34c2bc19501e9212d5 upstream.

The effective values of the guest CR0 and CR4 registers may differ from
those included in the VMCS12.  In particular, disabling EPT forces
CR4.PAE=1 and disabling unrestricted guest mode forces CR0.PG=CR0.PE=1.

Therefore, checks on these bits cannot be delegated to the processor
and must be performed by KVM.

Reported-by: Reima ISHII <ishiir@g.ecc.u-tokyo.ac.jp>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index d3a8ee0ef988a37647c0265242968ad79fd9b762..cd96c31fe2bb41ac82a282502f045bd4672299b1 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2779,7 +2779,7 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu,
                                        struct vmcs12 *vmcs12,
                                        u32 *exit_qual)
 {
-       bool ia32e;
+       bool ia32e = !!(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE);
 
        *exit_qual = ENTRY_FAIL_DEFAULT;
 
@@ -2796,6 +2796,13 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu,
                return -EINVAL;
        }
 
+       if (CC((vmcs12->guest_cr0 & (X86_CR0_PG | X86_CR0_PE)) == X86_CR0_PG))
+               return -EINVAL;
+
+       if (CC(ia32e && !(vmcs12->guest_cr4 & X86_CR4_PAE)) ||
+           CC(ia32e && !(vmcs12->guest_cr0 & X86_CR0_PG)))
+               return -EINVAL;
+
        /*
         * If the load IA32_EFER VM-entry control is 1, the following checks
         * are performed on the field for the IA32_EFER MSR:
@@ -2807,7 +2814,6 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu,
         */
        if (to_vmx(vcpu)->nested.nested_run_pending &&
            (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_EFER)) {
-               ia32e = (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) != 0;
                if (CC(!kvm_valid_efer(vcpu, vmcs12->guest_ia32_efer)) ||
                    CC(ia32e != !!(vmcs12->guest_ia32_efer & EFER_LMA)) ||
                    CC(((vmcs12->guest_cr0 & X86_CR0_PG) &&