virtio_pci: move structure to a header

Message ID 110d3058179284b092722827bef4f74f8ba0c622.1698769192.git.mst@redhat.com
State New
Headers
Series virtio_pci: move structure to a header |

Commit Message

Michael S. Tsirkin Oct. 31, 2023, 4:19 p.m. UTC
  These are guest/host interfaces so belong in the header
where e.g. qemu will know to find them.
Note: we added a new structure as opposed to extending existing one
because someone might be relying on the size of the existing structure
staying unchanged.  Add a warning to avoid using sizeof.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/virtio/virtio_pci_modern_dev.c |  7 ++++---
 include/linux/virtio_pci_modern.h      |  7 -------
 include/uapi/linux/virtio_pci.h        | 11 +++++++++++
 3 files changed, 15 insertions(+), 10 deletions(-)
  

Comments

Jason Wang Nov. 1, 2023, 12:38 a.m. UTC | #1
On Wed, Nov 1, 2023 at 12:20 AM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> These are guest/host interfaces so belong in the header
> where e.g. qemu will know to find them.
> Note: we added a new structure as opposed to extending existing one
> because someone might be relying on the size of the existing structure
> staying unchanged.  Add a warning to avoid using sizeof.
>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

> ---
>  drivers/virtio/virtio_pci_modern_dev.c |  7 ++++---
>  include/linux/virtio_pci_modern.h      |  7 -------
>  include/uapi/linux/virtio_pci.h        | 11 +++++++++++
>  3 files changed, 15 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
> index e2a1fe7bb66c..7de8b1ebabac 100644
> --- a/drivers/virtio/virtio_pci_modern_dev.c
> +++ b/drivers/virtio/virtio_pci_modern_dev.c
> @@ -294,9 +294,10 @@ int vp_modern_probe(struct virtio_pci_modern_device *mdev)
>
>         err = -EINVAL;
>         mdev->common = vp_modern_map_capability(mdev, common,
> -                                     sizeof(struct virtio_pci_common_cfg), 4,
> -                                     0, sizeof(struct virtio_pci_modern_common_cfg),
> -                                     &mdev->common_len, NULL);
> +                             sizeof(struct virtio_pci_common_cfg), 4, 0,
> +                             offsetofend(struct virtio_pci_modern_common_cfg,
> +                                         queue_reset),
> +                             &mdev->common_len, NULL);
>         if (!mdev->common)
>                 goto err_map_common;
>         mdev->isr = vp_modern_map_capability(mdev, isr, sizeof(u8), 1,
> diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
> index d0f2797420f7..a09e13a577a9 100644
> --- a/include/linux/virtio_pci_modern.h
> +++ b/include/linux/virtio_pci_modern.h
> @@ -5,13 +5,6 @@
>  #include <linux/pci.h>
>  #include <linux/virtio_pci.h>
>
> -struct virtio_pci_modern_common_cfg {
> -       struct virtio_pci_common_cfg cfg;
> -
> -       __le16 queue_notify_data;       /* read-write */
> -       __le16 queue_reset;             /* read-write */
> -};
> -
>  /**
>   * struct virtio_pci_modern_device - info for modern PCI virtio
>   * @pci_dev:       Ptr to the PCI device struct
> diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
> index f703afc7ad31..44f4dd2add18 100644
> --- a/include/uapi/linux/virtio_pci.h
> +++ b/include/uapi/linux/virtio_pci.h
> @@ -166,6 +166,17 @@ struct virtio_pci_common_cfg {
>         __le32 queue_used_hi;           /* read-write */
>  };
>
> +/*
> + * Warning: do not use sizeof on this: use offsetofend for
> + * specific fields you need.
> + */
> +struct virtio_pci_modern_common_cfg {
> +       struct virtio_pci_common_cfg cfg;
> +
> +       __le16 queue_notify_data;       /* read-write */
> +       __le16 queue_reset;             /* read-write */
> +};
> +
>  /* Fields in VIRTIO_PCI_CAP_PCI_CFG: */
>  struct virtio_pci_cfg_cap {
>         struct virtio_pci_cap cap;
> --
> MST
>
  
Xuan Zhuo Nov. 1, 2023, 1:45 a.m. UTC | #2
On Tue, 31 Oct 2023 12:19:54 -0400, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> These are guest/host interfaces so belong in the header
> where e.g. qemu will know to find them.
> Note: we added a new structure as opposed to extending existing one
> because someone might be relying on the size of the existing structure
> staying unchanged.  Add a warning to avoid using sizeof.
>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>

> ---
>  drivers/virtio/virtio_pci_modern_dev.c |  7 ++++---
>  include/linux/virtio_pci_modern.h      |  7 -------
>  include/uapi/linux/virtio_pci.h        | 11 +++++++++++
>  3 files changed, 15 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
> index e2a1fe7bb66c..7de8b1ebabac 100644
> --- a/drivers/virtio/virtio_pci_modern_dev.c
> +++ b/drivers/virtio/virtio_pci_modern_dev.c
> @@ -294,9 +294,10 @@ int vp_modern_probe(struct virtio_pci_modern_device *mdev)
>
>  	err = -EINVAL;
>  	mdev->common = vp_modern_map_capability(mdev, common,
> -				      sizeof(struct virtio_pci_common_cfg), 4,
> -				      0, sizeof(struct virtio_pci_modern_common_cfg),
> -				      &mdev->common_len, NULL);
> +			      sizeof(struct virtio_pci_common_cfg), 4, 0,
> +			      offsetofend(struct virtio_pci_modern_common_cfg,
> +					  queue_reset),
> +			      &mdev->common_len, NULL);
>  	if (!mdev->common)
>  		goto err_map_common;
>  	mdev->isr = vp_modern_map_capability(mdev, isr, sizeof(u8), 1,
> diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
> index d0f2797420f7..a09e13a577a9 100644
> --- a/include/linux/virtio_pci_modern.h
> +++ b/include/linux/virtio_pci_modern.h
> @@ -5,13 +5,6 @@
>  #include <linux/pci.h>
>  #include <linux/virtio_pci.h>
>
> -struct virtio_pci_modern_common_cfg {
> -	struct virtio_pci_common_cfg cfg;
> -
> -	__le16 queue_notify_data;	/* read-write */
> -	__le16 queue_reset;		/* read-write */
> -};
> -
>  /**
>   * struct virtio_pci_modern_device - info for modern PCI virtio
>   * @pci_dev:	    Ptr to the PCI device struct
> diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
> index f703afc7ad31..44f4dd2add18 100644
> --- a/include/uapi/linux/virtio_pci.h
> +++ b/include/uapi/linux/virtio_pci.h
> @@ -166,6 +166,17 @@ struct virtio_pci_common_cfg {
>  	__le32 queue_used_hi;		/* read-write */
>  };
>
> +/*
> + * Warning: do not use sizeof on this: use offsetofend for
> + * specific fields you need.
> + */
> +struct virtio_pci_modern_common_cfg {
> +	struct virtio_pci_common_cfg cfg;
> +
> +	__le16 queue_notify_data;	/* read-write */
> +	__le16 queue_reset;		/* read-write */
> +};
> +
>  /* Fields in VIRTIO_PCI_CAP_PCI_CFG: */
>  struct virtio_pci_cfg_cap {
>  	struct virtio_pci_cap cap;
> --
> MST
>
> _______________________________________________
> Virtualization mailing list
> Virtualization@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/virtualization
  

Patch

diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
index e2a1fe7bb66c..7de8b1ebabac 100644
--- a/drivers/virtio/virtio_pci_modern_dev.c
+++ b/drivers/virtio/virtio_pci_modern_dev.c
@@ -294,9 +294,10 @@  int vp_modern_probe(struct virtio_pci_modern_device *mdev)
 
 	err = -EINVAL;
 	mdev->common = vp_modern_map_capability(mdev, common,
-				      sizeof(struct virtio_pci_common_cfg), 4,
-				      0, sizeof(struct virtio_pci_modern_common_cfg),
-				      &mdev->common_len, NULL);
+			      sizeof(struct virtio_pci_common_cfg), 4, 0,
+			      offsetofend(struct virtio_pci_modern_common_cfg,
+					  queue_reset),
+			      &mdev->common_len, NULL);
 	if (!mdev->common)
 		goto err_map_common;
 	mdev->isr = vp_modern_map_capability(mdev, isr, sizeof(u8), 1,
diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
index d0f2797420f7..a09e13a577a9 100644
--- a/include/linux/virtio_pci_modern.h
+++ b/include/linux/virtio_pci_modern.h
@@ -5,13 +5,6 @@ 
 #include <linux/pci.h>
 #include <linux/virtio_pci.h>
 
-struct virtio_pci_modern_common_cfg {
-	struct virtio_pci_common_cfg cfg;
-
-	__le16 queue_notify_data;	/* read-write */
-	__le16 queue_reset;		/* read-write */
-};
-
 /**
  * struct virtio_pci_modern_device - info for modern PCI virtio
  * @pci_dev:	    Ptr to the PCI device struct
diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
index f703afc7ad31..44f4dd2add18 100644
--- a/include/uapi/linux/virtio_pci.h
+++ b/include/uapi/linux/virtio_pci.h
@@ -166,6 +166,17 @@  struct virtio_pci_common_cfg {
 	__le32 queue_used_hi;		/* read-write */
 };
 
+/*
+ * Warning: do not use sizeof on this: use offsetofend for
+ * specific fields you need.
+ */
+struct virtio_pci_modern_common_cfg {
+	struct virtio_pci_common_cfg cfg;
+
+	__le16 queue_notify_data;	/* read-write */
+	__le16 queue_reset;		/* read-write */
+};
+
 /* Fields in VIRTIO_PCI_CAP_PCI_CFG: */
 struct virtio_pci_cfg_cap {
 	struct virtio_pci_cap cap;