Re: [PATCH v3 08/13] vdpa: add return value to get_config/set_config callbacks

[Stefano Garzarella <sgarzare@redhat.com>]

Adding Eli in the loop.

On Fri, Feb 05, 2021 at 11:20:11AM +0800, Jason Wang wrote:
>
>On 2021/2/5 上午1:22, Stefano Garzarella wrote:
>>All implementations of these callbacks already validate inputs.
>>
>>Let's return an error from these callbacks, so the caller doesn't
>>need to validate the input anymore.
>>
>>We update all implementations to return -EINVAL in case of invalid
>>input.
>>
>>Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
>>---
>>  include/linux/vdpa.h              | 18 ++++++++++--------
>>  drivers/vdpa/ifcvf/ifcvf_main.c   | 24 ++++++++++++++++--------
>>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 17 +++++++++++------
>>  drivers/vdpa/vdpa_sim/vdpa_sim.c  | 16 ++++++++++------
>>  4 files changed, 47 insertions(+), 28 deletions(-)
>>
>>diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
>>index 4ab5494503a8..0e0cbd5fb41b 100644
>>--- a/include/linux/vdpa.h
>>+++ b/include/linux/vdpa.h
>>@@ -157,6 +157,7 @@ struct vdpa_iova_range {
>>   *				@buf: buffer used to read to
>>   *				@len: the length to read from
>>   *				configuration space
>>+ *				Returns integer: success (0) or error (< 0)
>>   * @set_config:			Write to device specific configuration space
>>   *				@vdev: vdpa device
>>   *				@offset: offset from the beginning of
>>@@ -164,6 +165,7 @@ struct vdpa_iova_range {
>>   *				@buf: buffer used to write from
>>   *				@len: the length to write to
>>   *				configuration space
>>+ *				Returns integer: success (0) or error (< 0)
>>   * @get_generation:		Get device config generation (optional)
>>   *				@vdev: vdpa device
>>   *				Returns u32: device generation
>>@@ -231,10 +233,10 @@ struct vdpa_config_ops {
>>  	u32 (*get_vendor_id)(struct vdpa_device *vdev);
>>  	u8 (*get_status)(struct vdpa_device *vdev);
>>  	void (*set_status)(struct vdpa_device *vdev, u8 status);
>>-	void (*get_config)(struct vdpa_device *vdev, unsigned int offset,
>>-			   void *buf, unsigned int len);
>>-	void (*set_config)(struct vdpa_device *vdev, unsigned int offset,
>>-			   const void *buf, unsigned int len);
>>+	int (*get_config)(struct vdpa_device *vdev, unsigned int offset,
>>+			  void *buf, unsigned int len);
>>+	int (*set_config)(struct vdpa_device *vdev, unsigned int offset,
>>+			  const void *buf, unsigned int len);
>>  	u32 (*get_generation)(struct vdpa_device *vdev);
>>  	struct vdpa_iova_range (*get_iova_range)(struct vdpa_device *vdev);
>>@@ -329,8 +331,8 @@ static inline int vdpa_set_features(struct vdpa_device *vdev, u64 features)
>>  }
>>-static inline void vdpa_get_config(struct vdpa_device *vdev, unsigned offset,
>>-				   void *buf, unsigned int len)
>>+static inline int vdpa_get_config(struct vdpa_device *vdev, unsigned offset,
>>+				  void *buf, unsigned int len)
>>  {
>>          const struct vdpa_config_ops *ops = vdev->config;
>>@@ -339,8 +341,8 @@ static inline void vdpa_get_config(struct vdpa_device *vdev, unsigned offset,
>>  	 * 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);
>>+		return vdpa_set_features(vdev, 0);
>>+	return ops->get_config(vdev, offset, buf, len);
>>  }
>>  /**
>>diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
>>index 7c8bbfcf6c3e..f5e6a90d8114 100644
>>--- a/drivers/vdpa/ifcvf/ifcvf_main.c
>>+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
>>@@ -332,24 +332,32 @@ static u32 ifcvf_vdpa_get_vq_align(struct vdpa_device *vdpa_dev)
>>  	return IFCVF_QUEUE_ALIGNMENT;
>>  }
>>-static void ifcvf_vdpa_get_config(struct vdpa_device *vdpa_dev,
>>-				  unsigned int offset,
>>-				  void *buf, unsigned int len)
>>+static int ifcvf_vdpa_get_config(struct vdpa_device *vdpa_dev,
>>+				 unsigned int offset,
>>+				 void *buf, unsigned int len)
>>  {
>>  	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
>>-	WARN_ON(offset + len > sizeof(struct virtio_net_config));
>>+	if (offset + len > sizeof(struct virtio_net_config))
>>+		return -EINVAL;
>>+
>>  	ifcvf_read_net_config(vf, offset, buf, len);
>>+
>>+	return 0;
>>  }
>>-static void ifcvf_vdpa_set_config(struct vdpa_device *vdpa_dev,
>>-				  unsigned int offset, const void *buf,
>>-				  unsigned int len)
>>+static int ifcvf_vdpa_set_config(struct vdpa_device *vdpa_dev,
>>+				 unsigned int offset, const void *buf,
>>+				 unsigned int len)
>>  {
>>  	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
>>-	WARN_ON(offset + len > sizeof(struct virtio_net_config));
>>+	if (offset + len > sizeof(struct virtio_net_config))
>>+		return -EINVAL;
>>+
>>  	ifcvf_write_net_config(vf, offset, buf, len);
>>+
>>+	return 0;
>>  }
>>  static void ifcvf_vdpa_set_config_cb(struct vdpa_device *vdpa_dev,
>>diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>index 029822060017..9323b5ff7988 100644
>>--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>@@ -1796,20 +1796,25 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status)
>>  	ndev->mvdev.status |= VIRTIO_CONFIG_S_FAILED;
>>  }
>>-static void mlx5_vdpa_get_config(struct vdpa_device *vdev, unsigned int offset, void *buf,
>>-				 unsigned int len)
>>+static int mlx5_vdpa_get_config(struct vdpa_device *vdev, unsigned int offset, void *buf,
>>+				unsigned int len)
>>  {
>>  	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
>>  	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
>>-	if (offset + len < sizeof(struct virtio_net_config))
>>-		memcpy(buf, (u8 *)&ndev->config + offset, len);
>>+	if (offset + len > sizeof(struct virtio_net_config))
>>+		return -EINVAL;
>
>
>It looks to me we should use ">=" here?


Ehmm, I think it was wrong before this patch. If 'offset + len' is equal 
to 'sizeof(struct virtio_net_config)', should be okay to copy, no?

I think it's one of the rare cases where the copy and paste went well 
:-)

Should I fix this in a separate patch?

Thanks,
Stefano