[Qemu-devel] [PATCH] x86: Reboot CPU on triple fault - Version 3

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

Here comes a version that may hopefully make everyone happy: :)

Reset on triple fault, but only dump the CPU state to stderr and logfile
if -triple-fault was given as command line option.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 dyngen-exec.h        |    1 +
 target-i386/helper.c |   24 ++++++++++++++++++++++--
 vl.c                 |    9 +++++++++
 3 files changed, 32 insertions(+), 2 deletions(-)

Index: b/dyngen-exec.h
===================================================================
--- a/dyngen-exec.h
+++ b/dyngen-exec.h
@@ -86,6 +86,7 @@ typedef struct FILE FILE;
 extern int fprintf(FILE *, const char *, ...);
 extern int fputs(const char *, FILE *);
 extern int printf(const char *, ...);
+extern FILE *stderr;
 #undef NULL
 #define NULL 0
 
Index: b/target-i386/helper.c
===================================================================
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -1231,6 +1231,10 @@ 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);
+extern int warn_on_triple_fault;
+
 /*
  * Check nested exceptions and change to double or triple fault if
  * needed. It should only be called, if this is not an interrupt.
@@ -1248,8 +1252,24 @@ static int check_exception(int intno, in
         fprintf(logfile, "check_exception old: %x new %x\n",
                 env->old_exception, intno);
 
-    if (env->old_exception == EXCP08_DBLE)
-        cpu_abort(env, "triple fault");
+    if (env->old_exception == EXCP08_DBLE) {
+        if(env->intercept & INTERCEPT_SVM_MASK) {
+            /* most probably the virtual machine should not
+               be shut down but rather caught by the VMM */
+            vmexit(SVM_EXIT_SHUTDOWN, 0);
+        }
+        if (warn_on_triple_fault) {
+            fprintf(stderr, "qemu: warning: triple fault\n");
+            cpu_dump_state(env, stderr, fprintf, X86_DUMP_FPU | X86_DUMP_CCOP);
+            if (logfile) {
+                fprintf(logfile, "qemu: warning: triple fault\n");
+                cpu_dump_state(env, logfile, fprintf,
+                               X86_DUMP_FPU | X86_DUMP_CCOP);
+            }
+        }
+        qemu_system_reset_request();
+        return EXCP_HLT;
+    }
 
     if ((first_contributory && second_contributory)
         || (env->old_exception == EXCP0E_PAGE &&
Index: b/vl.c
===================================================================
--- a/vl.c
+++ b/vl.c
@@ -200,6 +200,7 @@ CharDriverState *serial_hds[MAX_SERIAL_P
 CharDriverState *parallel_hds[MAX_PARALLEL_PORTS];
 #ifdef TARGET_I386
 int win2k_install_hack = 0;
+int warn_on_triple_fault = 0;
 #endif
 int usb_enabled = 0;
 static VLANState *first_vlan;
@@ -7730,6 +7731,7 @@ static void help(int exitcode)
            "-std-vga        simulate a standard VGA card with VESA Bochs Extensions\n"
            "                (default is CL-GD5446 PCI VGA)\n"
            "-no-acpi        disable ACPI\n"
+           "-triple-fault   enable CPU state dump on triple fault\n"
 #endif
 #ifdef CONFIG_CURSES
            "-curses         use a curses/ncurses interface instead of SDL\n"
@@ -7852,6 +7854,7 @@ enum {
     QEMU_OPTION_old_param,
     QEMU_OPTION_clock,
     QEMU_OPTION_startdate,
+    QEMU_OPTION_triple_fault,
 };
 
 typedef struct QEMUOption {
@@ -7964,6 +7967,9 @@ const QEMUOption qemu_options[] = {
 #endif
     { "clock", HAS_ARG, QEMU_OPTION_clock },
     { "startdate", HAS_ARG, QEMU_OPTION_startdate },
+#if defined(TARGET_I386)
+    { "triple-fault", 0, QEMU_OPTION_triple_fault },
+#endif
     { NULL },
 };
 
@@ -8702,6 +8708,9 @@ int main(int argc, char **argv)
             case QEMU_OPTION_win2k_hack:
                 win2k_install_hack = 1;
                 break;
+            case QEMU_OPTION_triple_fault:
+                warn_on_triple_fault = 1;
+                break;
 #endif
 #ifdef USE_KQEMU
             case QEMU_OPTION_no_kqemu: