[RFC v4 08/11] vduse: Add config interrupt support

[Xie Yongji <xieyongji@xxxxxxxxxxxxx>]

This patch introduces a new ioctl VDUSE_INJECT_CONFIG_IRQ
to support injecting config interrupt.

Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 24 +++++++++++++++++++++++-
 include/uapi/linux/vduse.h         |  3 +++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 393bf99c48be..8042d3fa57f1 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -66,6 +66,8 @@ struct vduse_dev {
 	struct list_head send_list;
 	struct list_head recv_list;
 	struct list_head list;
+	struct vdpa_callback config_cb;
+	spinlock_t irq_lock;
 	bool connected;
 	int minor;
 	u16 vq_size_max;
@@ -483,6 +485,11 @@ static void vduse_dev_reset(struct vduse_dev *dev)
 	vduse_iotlb_del_range(dev, 0ULL, ULLONG_MAX);
 	vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
 
+	spin_lock(&dev->irq_lock);
+	dev->config_cb.callback = NULL;
+	dev->config_cb.private = NULL;
+	spin_unlock(&dev->irq_lock);
+
 	for (i = 0; i < dev->vq_num; i++) {
 		struct vduse_virtqueue *vq = &dev->vqs[i];
 
@@ -599,7 +606,12 @@ static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
 static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,
 				  struct vdpa_callback *cb)
 {
-	/* We don't support config interrupt */
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	spin_lock(&dev->irq_lock);
+	dev->config_cb.callback = cb->callback;
+	dev->config_cb.private = cb->private;
+	spin_unlock(&dev->irq_lock);
 }
 
 static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
@@ -913,6 +925,15 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 		spin_unlock_irq(&vq->irq_lock);
 		break;
 	}
+	case VDUSE_INJECT_CONFIG_IRQ:
+		ret = -EINVAL;
+		spin_lock_irq(&dev->irq_lock);
+		if (dev->config_cb.callback) {
+			dev->config_cb.callback(dev->config_cb.private);
+			ret = 0;
+		}
+		spin_unlock_irq(&dev->irq_lock);
+		break;
 	default:
 		ret = -ENOIOCTLCMD;
 		break;
@@ -996,6 +1017,7 @@ static struct vduse_dev *vduse_dev_create(void)
 	INIT_LIST_HEAD(&dev->recv_list);
 	atomic64_set(&dev->msg_unique, 0);
 	spin_lock_init(&dev->iommu_lock);
+	spin_lock_init(&dev->irq_lock);
 	atomic_set(&dev->bounce_map, 0);
 
 	init_waitqueue_head(&dev->waitq);
diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
index 9391c4acfa53..9070cd512cb4 100644
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -133,4 +133,7 @@ struct vduse_vq_eventfd {
 /* Inject an interrupt for specific virtqueue */
 #define VDUSE_INJECT_VQ_IRQ	_IO(VDUSE_BASE, 0x05)
 
+/* Inject a config interrupt */
+#define VDUSE_INJECT_CONFIG_IRQ	_IO(VDUSE_BASE, 0x06)
+
 #endif /* _UAPI_VDUSE_H_ */
-- 
2.11.0