arm_kvm: Do not assume particular GIC type in kvm_arch_irqchip_create()

This allows us to use different GIC types from v2. There are no kernels
which could advertise KVM_CAP_DEVICE_CTRL without the actual ability to
create GIC with it.

GIC version probe code moved to kvm_arm_vgic_probe() which will be used
later.
Signed-off-by: NPavel Fedin <p.fedin@samsung.com>
Reviewed-by: NEric Auger <eric.auger@linaro.org>
Tested-by: NAshok kumar <ashoks@broadcom.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Message-id: 015f4d9e4a8a50dfbdd734c4730558e24a69c6dc.1441784344.git.p.fedin@samsung.com
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target-arm/kvm.c

@@ -585,18 +585,23 @@ void kvm_arch_init_irq_routing(KVMState *s)
 
 int kvm_arch_irqchip_create(KVMState *s)
 {
-    int ret;
-
     /* If we can create the VGIC using the newer device control API, we
      * let the device do this when it initializes itself, otherwise we
      * fall back to the old API */
+    return kvm_check_extension(s, KVM_CAP_DEVICE_CTRL);
+}
 
-    ret = kvm_create_device(s, KVM_DEV_TYPE_ARM_VGIC_V2, true);
-    if (ret == 0) {
-        return 1;
-    }
-
+int kvm_arm_vgic_probe(void)
+{
+    if (kvm_create_device(kvm_state,
+                          KVM_DEV_TYPE_ARM_VGIC_V3, true) == 0) {
+        return 3;
+    } else if (kvm_create_device(kvm_state,
+                                 KVM_DEV_TYPE_ARM_VGIC_V2, true) == 0) {
+        return 2;
+    } else {
         return 0;
+    }
 }
 
 int kvm_arch_fixup_msi_route(struct kvm_irq_routing_entry *route,

target-arm/kvm_arm.h

@@ -189,6 +189,15 @@ int kvm_arm_sync_mpstate_to_kvm(ARMCPU *cpu);
  */
 int kvm_arm_sync_mpstate_to_qemu(ARMCPU *cpu);
 
+int kvm_arm_vgic_probe(void);
+
+#else
+
+static inline int kvm_arm_vgic_probe(void)
+{
+    return 0;
+}
+
 #endif
 
 static inline const char *gic_class_name(void)