[Qemu-devel] [PATCH v12 4/9] hw/vfio/platform: add capability to start IRQ propagation

[Eric Auger <eric.auger@linaro.org>]

Add a reset notify function that enables to start the propagation of
interrupts to the guest.

Signed-off-by: Eric Auger <eric.auger@linaro.org>

---
v10 -> v11:
- comment reword

v8 -> v9:
- handle failure in vfio_irq_starter
---
 hw/vfio/platform.c              | 64 +++++++++++++++++++++++++++++++++++++++++
 include/hw/vfio/vfio-platform.h |  8 ++++++
 2 files changed, 72 insertions(+)

diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c
index 31c2701..361e01b 100644
--- a/hw/vfio/platform.c
+++ b/hw/vfio/platform.c
@@ -572,6 +572,70 @@ static void vfio_platform_realize(DeviceState *dev, Error **errp)
     }
 }
 
+/**
+ * vfio_irq_starter: Start IRQ forwarding for a specific VFIO device
+ * @sbdev: Sysbus device handle
+ * @opaque: DeviceState handle of the interrupt controller the device
+ *          is attached to
+ *
+ * The function retrieves the absolute GSI number each VFIO IRQ
+ * corresponds to and start forwarding.
+ */
+static int vfio_irq_starter(SysBusDevice *sbdev, void *opaque)
+{
+    DeviceState *intc = (DeviceState *)opaque;
+    VFIOPlatformDevice *vdev;
+    VFIOINTp *intp;
+    qemu_irq irq;
+    int gsi, ret;
+
+    if (object_dynamic_cast(OBJECT(sbdev), TYPE_VFIO_PLATFORM)) {
+        vdev = VFIO_PLATFORM_DEVICE(sbdev);
+
+        QLIST_FOREACH(intp, &vdev->intp_list, next) {
+            gsi = 0;
+            while (1) {
+                irq = qdev_get_gpio_in(intc, gsi);
+                if (irq == intp->qemuirq) {
+                    break;
+                }
+                gsi++;
+            }
+            intp->virtualID = gsi;
+            ret = vdev->start_irq_fn(intp);
+            if (ret) {
+                error_report("%s unable to start propagation of IRQ index %d",
+                             vdev->vbasedev.name, intp->pin);
+                exit(1);
+            }
+        }
+    }
+    return 0;
+}
+
+/**
+ * vfio_kick_irqs: start IRQ forwarding for all the VFIO devices
+ * attached to the platform bus
+ * @data: Device state handle of the interrupt controller the VFIO IRQs
+ *        must be bound to
+ *
+ * Binding to the platform bus IRQs happens on a machine init done
+ * notifier registered by the platform bus. Only at that time the
+ * absolute virtual IRQ = GSI is known and allows to setup IRQFD.
+ * This function typically can be called in a reset notifier registered
+ * by the machine file.
+ */
+void vfio_kick_irqs(void *data)
+{
+    DeviceState *intc = (DeviceState *)data;
+    DeviceState *dev =
+        qdev_find_recursive(sysbus_get_default(), TYPE_PLATFORM_BUS_DEVICE);
+    PlatformBusDevice *pbus = PLATFORM_BUS_DEVICE(dev);
+
+    assert(pbus->done_gathering);
+    foreach_dynamic_sysbus_device(vfio_irq_starter, intc);
+}
+
 static const VMStateDescription vfio_platform_vmstate = {
     .name = TYPE_VFIO_PLATFORM,
     .unmigratable = 1,
diff --git a/include/hw/vfio/vfio-platform.h b/include/hw/vfio/vfio-platform.h
index 31893a3..c9ee898 100644
--- a/include/hw/vfio/vfio-platform.h
+++ b/include/hw/vfio/vfio-platform.h
@@ -77,4 +77,12 @@ typedef struct VFIOPlatformDeviceClass {
 #define VFIO_PLATFORM_DEVICE_GET_CLASS(obj) \
      OBJECT_GET_CLASS(VFIOPlatformDeviceClass, (obj), TYPE_VFIO_PLATFORM)
 
+/**
+ * vfio_kick_irqs - reset notifier that starts IRQ injection
+ * for all VFIO dynamic sysbus devices attached to the platform bus.
+ *
+ * @opaque: handle to the interrupt controller DeviceState
+ */
+void vfio_kick_irqs(void *opaque);
+
 #endif /*HW_VFIO_VFIO_PLATFORM_H*/
-- 
1.8.3.2