qemu-kvm: fix segfault when running kvm without /dev/kvm

qemu-kvm segfaults on systems without access to /dev/kvm.
The global kvm_allowed is being set too late in vl.c.

This patch moves the kvm initialization a bit higher in the
vl.c main, just after the daemonize fork.

This fix is intended to be a short term solution, solving the
segfaults.

In the longer term, the suggested approach requires a bit more
development and testing:
 * If no arg given          => try kvm, try kqemu, try tcg
 * If --accelmode arg given => try $arg, and fail if unavailable

Signed-off-by: Dustin Kirkland <address@hidden>

diff --git a/vl.c b/vl.c
index db75470..26bced8 100644
--- a/vl.c
+++ b/vl.c
@@ -5831,6 +5831,20 @@ int main(int argc, char **argv, char **envp)
     }
 #endif
 
+    if (kvm_enabled()) {
+        int ret;
+
+        ret = kvm_init(smp_cpus);
+        if (ret < 0) {
+#if defined(KVM_UPSTREAM) || defined(NO_CPU_EMULATION)
+            fprintf(stderr, "failed to initialize KVM\n");
+            exit(1);
+#endif
+            fprintf(stderr, "Could not initialize KVM, will disable KVM support\n");
+            kvm_allowed = 0;
+        }
+    }
+
 #ifdef CONFIG_KQEMU
     if (smp_cpus > 1)
         kqemu_allowed = 0;
@@ -6002,20 +6016,6 @@ int main(int argc, char **argv, char **envp)
         }
     }
 
-    if (kvm_enabled()) {
-        int ret;
-
-        ret = kvm_init(smp_cpus);
-        if (ret < 0) {
-#if defined(KVM_UPSTREAM) || defined(NO_CPU_EMULATION)
-            fprintf(stderr, "failed to initialize KVM\n");
-            exit(1);
-#endif
-            fprintf(stderr, "Could not initialize KVM, will disable KVM support\n");
-	     kvm_allowed = 0;
-        }
-    }
-
     if (monitor_device) {
         monitor_hd = qemu_chr_open("monitor", monitor_device, NULL);
         if (!monitor_hd) {