[PATCH v3 3/7] vduse: Add new ioctl VDUSE_DEV_GET_CONFIG

[Cindy Lu <lulu@redhat.com>]

The ioctl VDUSE_GET_RECONNECT_INFO is used by the Userspace App
to get the device configuration space.

Signed-off-by: Cindy Lu <lulu@redhat.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 21 +++++++++++++++++++++
 include/uapi/linux/vduse.h         |  3 +++
 2 files changed, 24 insertions(+)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 26b7e29cb900..dd074a7b4bc7 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -1273,6 +1273,27 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 		ret = 0;
 		break;
 	}
+	case VDUSE_DEV_GET_CONFIG: {
+		struct vduse_config_data config;
+		unsigned long size = offsetof(struct vduse_config_data, buffer);
+
+		ret = -EFAULT;
+		if (copy_from_user(&config, argp, size))
+			break;
+
+		ret = -EINVAL;
+		if (config.offset > dev->config_size || config.length == 0 ||
+		    config.length > dev->config_size - config.offset)
+			break;
+
+		if (copy_to_user(argp + size, dev->config + config.offset,
+				 config.length)) {
+			ret = -EFAULT;
+			break;
+		}
+		ret = 0;
+		break;
+	}
 	default:
 		ret = -ENOIOCTLCMD;
 		break;
diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
index c22838247814..5280042ced23 100644
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -372,4 +372,7 @@ struct vduse_dev_reconnect_data {
 /* the reconnection mmap size for each VQ and dev status */
 #define VDUSE_RECONNCT_MMAP_SIZE PAGE_SIZE
 
+/* get device configuration space */
+#define VDUSE_DEV_GET_CONFIG _IOR(VDUSE_BASE, 0x1b, struct vduse_config_data)
+
 #endif /* _UAPI_VDUSE_H_ */
-- 
2.34.3