Change the logging not to print to stderr as well, because a
checkstop is a guest error (or perhaps a simulated machine error)
rather than a QEMU error, so send it to the log.

Update the checkstop message, and log CPU registers too.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Glenn Miles <milesg@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/excp_helper.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index fd00c044b5..a283c97717 100644
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -430,17 +430,19 @@ static void powerpc_mcheck_checkstop(CPUPPCState *env)
     /* KVM guests always have MSR[ME] enabled */
 #ifdef CONFIG_TCG
     CPUState *cs = env_cpu(env);
+    FILE *f;
 
     if (FIELD_EX64(env->msr, MSR, ME)) {
         return;
     }
 
-    /* Machine check exception is not enabled. Enter checkstop state. */
-    fprintf(stderr, "Machine check while not allowed. "
-            "Entering checkstop state\n");
-    if (qemu_log_separate()) {
-        qemu_log("Machine check while not allowed. "
-                 "Entering checkstop state\n");
+    f = qemu_log_trylock();
+    if (f) {
+        fprintf(f, "Entering checkstop state: "
+                   "machine check with MSR[ME]=0\n");
+        cpu_dump_state(cs, f, CPU_DUMP_FPU | CPU_DUMP_CCOP);
+        qemu_log_unlock(f);
+    }
 
     /*
      * This stops the machine and logs CPU state without killing QEMU
-- 
2.43.0