[Qemu-devel] [RFC PATCH v2 2/4] kvm: Introduce kvm_arch_irqchip_create

[Christoffer Dall <christoffer.dall@linaro.org>]

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.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

---
Changelog[v2]:
 - Proper formatted function comments
 - Use QEMU's stubs mechanism for KVM stubs
---
 include/sysemu/kvm.h |   12 ++++++++++++
 kvm-all.c            |   11 +++++++++--
 stubs/Makefile.objs  |    1 +
 stubs/kvm.c          |    7 +++++++
 4 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 stubs/kvm.c

diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index de74411..fbb2776 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -314,4 +314,16 @@ 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
diff --git a/kvm-all.c b/kvm-all.c
index 716860f..fe64f3b 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1295,10 +1295,17 @@ 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;
diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index f306cba..f3eba26 100644
--- a/stubs/Makefile.objs
+++ b/stubs/Makefile.objs
@@ -26,3 +26,4 @@ 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
diff --git a/stubs/kvm.c b/stubs/kvm.c
new file mode 100644
index 0000000..e7c60b6
--- /dev/null
+++ b/stubs/kvm.c
@@ -0,0 +1,7 @@
+#include "qemu-common.h"
+#include "sysemu/kvm.h"
+
+int kvm_arch_irqchip_create(KVMState *s)
+{
+    return 0;
+}
-- 
1.7.10.4