[Qemu-devel] [RESEND][PATCH 2/2] x86: Issue reset on triple faults

[Jan Kiszka <jan.kiszka@siemens.com>]

As discussed a few times on this list: A triple fault causes a system
reset on x86, and some guests make use of this. To keep the chance of
tracing unexpected resets, log them if CPU_LOG_RESET is set.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 target-i386/op_helper.c |   17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

Index: b/target-i386/op_helper.c
===================================================================
--- a/target-i386/op_helper.c
+++ b/target-i386/op_helper.c
@@ -1286,6 +1286,9 @@ void do_interrupt(int intno, int is_int,
     }
 }
 
+/* This should come from sysemu.h - if we could include it here... */
+void qemu_system_reset_request(void);
+
 /*
  * Check nested exceptions and change to double or triple fault if
  * needed. It should only be called, if this is not an interrupt.
@@ -1303,8 +1306,18 @@ static int check_exception(int intno, in
         fprintf(logfile, "check_exception old: 0x%x new 0x%x\n",
                 env->old_exception, intno);
 
-    if (env->old_exception == EXCP08_DBLE)
-        cpu_abort(env, "triple fault");
+#if !defined(CONFIG_USER_ONLY)
+    if (env->old_exception == EXCP08_DBLE) {
+        if (env->hflags & HF_SVMI_MASK)
+            helper_vmexit(SVM_EXIT_SHUTDOWN, 0); /* does not return */
+
+        if (loglevel & CPU_LOG_RESET)
+            fprintf(logfile, "Triple fault\n");
+
+        qemu_system_reset_request();
+        return EXCP_HLT;
+    }
+#endif
 
     if ((first_contributory && second_contributory)
         || (env->old_exception == EXCP0E_PAGE &&