kvm: vmx: Introduce VMCS12_MAX_FIELD_INDEX

This is the highest index value used in any supported VMCS12 field
encoding. It is used to populate the IA32_VMX_VMCS_ENUM MSR.
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

arch/x86/kvm/vmx.c

@@ -407,6 +407,12 @@ struct __packed vmcs12 {
  */
 #define VMCS12_SIZE 0x1000
 
+/*
+ * VMCS12_MAX_FIELD_INDEX is the highest index value used in any
+ * supported VMCS12 field encoding.
+ */
+#define VMCS12_MAX_FIELD_INDEX 0x17
+
 /*
  * The nested_vmx structure is part of vcpu_vmx, and holds information we need
  * for correct emulation of VMX (i.e., nested VMX) on this vcpu.
@@ -2923,7 +2929,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 	rdmsrl(MSR_IA32_VMX_CR4_FIXED1, vmx->nested.nested_vmx_cr4_fixed1);
 
 	/* highest index: VMX_PREEMPTION_TIMER_VALUE */
-	vmx->nested.nested_vmx_vmcs_enum = 0x2e;
+	vmx->nested.nested_vmx_vmcs_enum = VMCS12_MAX_FIELD_INDEX << 1;
 }
 
 /*