kvm: Introduce kvm_arch_irqchip_create

Introduce kvm_arch_irqchip_create an arch-specific hook in preparation
for architecture-specific use of the device control API to create IRQ
chips.

Following patches will implement the ARM irqchip create method to prefer
the device control API over the older KVM_CREATE_IRQCHIP API.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Message-id: 1392687720-26806-3-git-send-email-christoffer.dall@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

include/sysemu/kvm.h

@@ -319,4 +319,16 @@ int kvm_irqchip_remove_irqfd_notifier(KVMState *s, EventNotifier *n, int virq);
 void kvm_pc_gsi_handler(void *opaque, int n, int level);
 void kvm_pc_setup_irq_routing(bool pci_enabled);
 void kvm_init_irq_routing(KVMState *s);
+
+/**
+ * kvm_arch_irqchip_create:
+ * @KVMState: The KVMState pointer
+ *
+ * Allow architectures to create an in-kernel irq chip themselves.
+ *
+ * Returns: < 0: error
+ *            0: irq chip was not created
+ *          > 0: irq chip was created
+ */
+int kvm_arch_irqchip_create(KVMState *s);
 #endif

kvm-all.c

@@ -1298,10 +1298,17 @@ static int kvm_irqchip_create(KVMState *s)
         return 0;
     }
 
-    ret = kvm_vm_ioctl(s, KVM_CREATE_IRQCHIP);
+    /* 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) {
-        fprintf(stderr, "Create kernel irqchip failed\n");
         return ret;
+    } else if (ret == 0) {
+        ret = kvm_vm_ioctl(s, KVM_CREATE_IRQCHIP);
+        if (ret < 0) {
+            fprintf(stderr, "Create kernel irqchip failed\n");
+            return ret;
+        }
     }
 
     kvm_kernel_irqchip = true;

stubs/Makefile.objs

@@ -27,3 +27,4 @@ stub-obj-y += vm-stop.o
 stub-obj-y += vmstate.o
 stub-obj-$(CONFIG_WIN32) += fd-register.o
 stub-obj-y += cpus.o
+stub-obj-y += kvm.o

stubs/kvm.c

@@ -0,0 +1,7 @@
+#include "qemu-common.h"
+#include "sysemu/kvm.h"
+
+int kvm_arch_irqchip_create(KVMState *s)
+{
+    return 0;
+}