kvm-all: kvm_irqchip_create is not expected to fail

KVM_CREATE_IRQCHIP should never fail, and so should its userspace
wrapper kvm_irqchip_create.  The function does not do anything
if the irqchip capability is not available, as is the case for PPC.

With this patch, kvm_arch_init can allocate memory and it will not
be leaked.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

kvm-all.c

@@ -1345,27 +1345,31 @@ int kvm_irqchip_remove_irqfd_notifier(KVMState *s, EventNotifier *n, int virq)
            false);
 }
 
-static int kvm_irqchip_create(MachineState *machine, KVMState *s)
+static void kvm_irqchip_create(MachineState *machine, KVMState *s)
 {
     int ret;
 
-    if (!machine_kernel_irqchip_allowed(machine) ||
-        (!kvm_check_extension(s, KVM_CAP_IRQCHIP) &&
-         (kvm_vm_enable_cap(s, KVM_CAP_S390_IRQCHIP, 0) < 0))) {
-        return 0;
+    if (kvm_check_extension(s, KVM_CAP_IRQCHIP)) {
+        ;
+    } else if (kvm_check_extension(s, KVM_CAP_S390_IRQCHIP)) {
+        ret = kvm_vm_enable_cap(s, KVM_CAP_S390_IRQCHIP, 0);
+        if (ret < 0) {
+            fprintf(stderr, "Enable kernel irqchip failed: %s\n", strerror(-ret));
+            exit(1);
+        }
+    } else {
+        return;
     }
 
     /* First probe and see if there's a arch-specific hook to create the
      * in-kernel irqchip for us */
     ret = kvm_arch_irqchip_create(s);
-    if (ret < 0) {
-        return ret;
-    } else if (ret == 0) {
+    if (ret == 0) {
         ret = kvm_vm_ioctl(s, KVM_CREATE_IRQCHIP);
-        if (ret < 0) {
-            fprintf(stderr, "Create kernel irqchip failed\n");
-            return ret;
-        }
+    }
+    if (ret < 0) {
+        fprintf(stderr, "Create kernel irqchip failed: %s\n", strerror(-ret));
+        exit(1);
     }
 
     kvm_kernel_irqchip = true;
@@ -1376,8 +1380,6 @@ static int kvm_irqchip_create(MachineState *machine, KVMState *s)
     kvm_halt_in_kernel_allowed = true;
 
     kvm_init_irq_routing(s);
-
-    return 0;
 }
 
 /* Find number of supported CPUs using the recommended
@@ -1594,9 +1596,8 @@ static int kvm_init(MachineState *ms)
         goto err;
     }
 
-    ret = kvm_irqchip_create(ms, s);
-    if (ret < 0) {
-        goto err;
+    if (machine_kernel_irqchip_allowed(ms)) {
+        kvm_irqchip_create(ms, s);
     }
 
     kvm_state = s;