target-i386: Mark cpu_vmexit noreturn

It calls cpu_loop_exit in system emulation mode (and should never be
called in user emulation mode).
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Message-Id: <6f4d44ffde55d074cbceb48309c1678600abad2f.1522769774.git.jan.kiszka@web.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

target/i386/cpu.h

@@ -1840,8 +1840,8 @@ void helper_lock_init(void);
 /* svm_helper.c */
 void cpu_svm_check_intercept_param(CPUX86State *env1, uint32_t type,
                                    uint64_t param, uintptr_t retaddr);
-void cpu_vmexit(CPUX86State *nenv, uint32_t exit_code, uint64_t exit_info_1,
-                uintptr_t retaddr);
+void QEMU_NORETURN cpu_vmexit(CPUX86State *nenv, uint32_t exit_code,
+                              uint64_t exit_info_1, uintptr_t retaddr);
 void do_vmexit(CPUX86State *env, uint32_t exit_code, uint64_t exit_info_1);
 
 /* seg_helper.c */

target/i386/svm_helper.c

@@ -62,6 +62,7 @@ void helper_invlpga(CPUX86State *env, int aflag)
 void cpu_vmexit(CPUX86State *nenv, uint32_t exit_code, uint64_t exit_info_1,
                 uintptr_t retaddr)
 {
+    assert(0);
 }
 
 void helper_svm_check_intercept_param(CPUX86State *env, uint32_t type,