KVM: nVMX: Unrestricted guest mode requires EPT

As specified in Intel's SDM, do not allow the L1 hypervisor to launch
an L2 guest with the VM-execution controls for "unrestricted guest" or
"mode-based execute control for EPT" set and the VM-execution control
for "enable EPT" clear.

Note that the VM-execution control for "mode-based execute control for
EPT" is not yet virtualized by kvm.
Reported-by: Andrew Thornton <andrewth@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Wanpeng Li <wanpengli@tencent.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/vmx.h

@@ -78,6 +78,7 @@
 #define SECONDARY_EXEC_RDSEED_EXITING		0x00010000
 #define SECONDARY_EXEC_ENABLE_PML               0x00020000
 #define SECONDARY_EXEC_XSAVES			0x00100000
+#define SECONDARY_EXEC_MODE_BASED_EPT_EXEC	0x00400000
 #define SECONDARY_EXEC_TSC_SCALING              0x02000000
 
 #define PIN_BASED_EXT_INTR_MASK                 0x00000001

arch/x86/kvm/vmx.c

@@ -12308,6 +12308,24 @@ static int nested_vmx_check_pml_controls(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
+static int nested_vmx_check_unrestricted_guest_controls(struct kvm_vcpu *vcpu,
+							struct vmcs12 *vmcs12)
+{
+	if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_UNRESTRICTED_GUEST) &&
+	    !nested_cpu_has_ept(vmcs12))
+		return -EINVAL;
+	return 0;
+}
+
+static int nested_vmx_check_mode_based_ept_exec_controls(struct kvm_vcpu *vcpu,
+							 struct vmcs12 *vmcs12)
+{
+	if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_MODE_BASED_EPT_EXEC) &&
+	    !nested_cpu_has_ept(vmcs12))
+		return -EINVAL;
+	return 0;
+}
+
 static int nested_vmx_check_shadow_vmcs_controls(struct kvm_vcpu *vcpu,
 						 struct vmcs12 *vmcs12)
 {
@@ -13036,6 +13054,12 @@ static int check_vmentry_prereqs(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 	if (nested_vmx_check_pml_controls(vcpu, vmcs12))
 		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
 
+	if (nested_vmx_check_unrestricted_guest_controls(vcpu, vmcs12))
+		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
+
+	if (nested_vmx_check_mode_based_ept_exec_controls(vcpu, vmcs12))
+		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
+
 	if (nested_vmx_check_shadow_vmcs_controls(vcpu, vmcs12))
 		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;