2023-10-31 16:21:03

by Michael S. Tsirkin

[permalink] [raw]
Subject: [PATCH] virtio_pci: move structure to a header

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 <[email protected]>
---
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


2023-11-01 00:39:33

by Jason Wang

[permalink] [raw]
Subject: Re: [PATCH] virtio_pci: move structure to a header

On Wed, Nov 1, 2023 at 12:20 AM Michael S. Tsirkin <[email protected]> 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 <[email protected]>

Acked-by: Jason Wang <[email protected]>

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
>

2023-11-01 01:46:32

by Xuan Zhuo

[permalink] [raw]
Subject: Re: [PATCH] virtio_pci: move structure to a header

On Tue, 31 Oct 2023 12:19:54 -0400, "Michael S. Tsirkin" <[email protected]> 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 <[email protected]>

Reviewed-by: Xuan Zhuo <[email protected]>

> ---
> 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
>
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