+/*
+ * Adjust a single secondary execution control bit to intercept/allow an
+ * instruction in the guest. This is usually done based on whether or not a
+ * feature has been exposed to the guest in order to correctly emulate faults.
+ */
+static inline void
+vmx_adjust_secondary_exec_control(struct vcpu_vmx *vmx, u32 *exec_control,
+ u32 control, bool enabled, bool exiting)
+{
+ /*
+ * If the control is for an opt-in feature, clear the control if the
+ * feature is not exposed to the guest, i.e. not enabled. If the
+ * control is opt-out, i.e. an exiting control, clear the control if
+ * the feature _is_ exposed to the guest, i.e. exiting/interception is
+ * disabled for the associated instruction. Note, the caller is
+ * responsible presetting exec_control to set all supported bits.
+ */
+ if (enabled == exiting)
+ *exec_control &= ~control;
+
+ /*
+ * Update the nested MSR settings so that a nested VMM can/can't set
+ * controls for features that are/aren't exposed to the guest.
+ */
+ if (nested) {
+ if (enabled)
+ vmx->nested.msrs.secondary_ctls_high |= control;
+ else
+ vmx->nested.msrs.secondary_ctls_high &= ~control;
+ }
+}
+
+/*
+ * Wrapper macro for the common case of adjusting a secondary execution control
+ * based on a single guest CPUID bit, with a dedicated feature bit. This also
+ * verifies that the control is actually supported by KVM and hardware.
+ */
+#define vmx_adjust_sec_exec_control(vmx, exec_control, name, feat_name, ctrl_name, exiting) \
+({ \
+ bool __enabled; \
+ \
+ if (cpu_has_vmx_##name()) { \
+ __enabled = guest_cpuid_has(&(vmx)->vcpu, \
+ X86_FEATURE_##feat_name); \
+ vmx_adjust_secondary_exec_control(vmx, exec_control, \
+ SECONDARY_EXEC_##ctrl_name, __enabled, exiting); \
+ } \
+})
+
+/* More macro magic for ENABLE_/opt-in versus _EXITING/opt-out controls. */
+#define vmx_adjust_sec_exec_feature(vmx, exec_control, lname, uname) \
+ vmx_adjust_sec_exec_control(vmx, exec_control, lname, uname, ENABLE_##uname, false)
+
+#define vmx_adjust_sec_exec_exiting(vmx, exec_control, lname, uname) \
+ vmx_adjust_sec_exec_control(vmx, exec_control, lname, uname, uname##_EXITING, true)