3 files changed, 38 insertions, 4 deletions
diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index fcf02a364878..cbc8fc69cf9b 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -297,6 +297,42 @@ void vdpa_mgmtdev_unregister(struct vdpa_mgmt_dev *mdev)
 }
 EXPORT_SYMBOL_GPL(vdpa_mgmtdev_unregister);
 
+/**
+ * vdpa_get_config - Get one or more device configuration fields.
+ * @vdev: vdpa device to operate on
+ * @offset: starting byte offset of the field
+ * @buf: buffer pointer to read to
+ * @len: length of the configuration fields in bytes
+ */
+void vdpa_get_config(struct vdpa_device *vdev, unsigned int offset,
+		     void *buf, unsigned int len)
+{
+	const struct vdpa_config_ops *ops = vdev->config;
+
+	/*
+	 * Config accesses aren't supposed to trigger before features are set.
+	 * If it does happen we assume a legacy guest.
+	 */
+	if (!vdev->features_valid)
+		vdpa_set_features(vdev, 0);
+	ops->get_config(vdev, offset, buf, len);
+}
+EXPORT_SYMBOL_GPL(vdpa_get_config);
+
+/**
+ * vdpa_set_config - Set one or more device configuration fields.
+ * @vdev: vdpa device to operate on
+ * @offset: starting byte offset of the field
+ * @buf: buffer pointer to read from
+ * @length: length of the configuration fields in bytes
+ */
+void vdpa_set_config(struct vdpa_device *vdev, unsigned int offset,
+		     const void *buf, unsigned int length)
+{
+	vdev->config->set_config(vdev, offset, buf, length);
+}
+EXPORT_SYMBOL_GPL(vdpa_set_config);
+
 static bool mgmtdev_handle_match(const struct vdpa_mgmt_dev *mdev,
 				 const char *busname, const char *devname)
 {
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 39039e046117..01c59ce7e250 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -237,7 +237,6 @@ static long vhost_vdpa_set_config(struct vhost_vdpa *v,
 				  struct vhost_vdpa_config __user *c)
 {
 	struct vdpa_device *vdpa = v->vdpa;
-	const struct vdpa_config_ops *ops = vdpa->config;
 	struct vhost_vdpa_config config;
 	unsigned long size = offsetof(struct vhost_vdpa_config, buf);
 	u8 *buf;
@@ -251,7 +250,7 @@ static long vhost_vdpa_set_config(struct vhost_vdpa *v,
 	if (IS_ERR(buf))
 		return PTR_ERR(buf);
 
-	ops->set_config(vdpa, config.off, buf, config.len);
+	vdpa_set_config(vdpa, config.off, buf, config.len);
 
 	kvfree(buf);
 	return 0;
diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
index 6b62aaf08cc5..f85f860bc10b 100644
--- a/drivers/virtio/virtio_vdpa.c
+++ b/drivers/virtio/virtio_vdpa.c
@@ -65,9 +65,8 @@ static void virtio_vdpa_set(struct virtio_device *vdev, unsigned offset,
 			    const void *buf, unsigned len)
 {
 	struct vdpa_device *vdpa = vd_get_vdpa(vdev);
-	const struct vdpa_config_ops *ops = vdpa->config;
 
-	ops->set_config(vdpa, offset, buf, len);
+	vdpa_set_config(vdpa, offset, buf, len);
 }
 
 static u32 virtio_vdpa_generation(struct virtio_device *vdev)