Re: [PATCH V4 vfio 8/9] vfio/pci: Expose vfio_pci_iowrite/read##size()

Alex Williamson
2023-11-30T19:20:17Z

On Wed, 29 Nov 2023 16:37:45 +0200
Yishai Hadas <yishaih@nvidia.com> wrote:

> Expose vfio_pci_iowrite/read##size() to let it be used by drivers.
>
> This functionality is needed to enable direct access to some physical
> BAR of the device with the proper locks/checks in place.
>
> The next patches from this series will use this functionality on a data
> path flow when a direct access to the BAR is needed.
>
> Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
> ---
> drivers/vfio/pci/vfio_pci_rdwr.c | 10 ++++++----
> include/linux/vfio_pci_core.h | 19 +++++++++++++++++++
> 2 files changed, 25 insertions(+), 4 deletions(-)

I don't follow the inconsistency between this and the previous patch.
Why did we move and rename the code to setup the barmap but we export
the ioread/write functions in place? Thanks,

Alex

> diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
> index 6f08b3ecbb89..817ec9a89123 100644
> --- a/drivers/vfio/pci/vfio_pci_rdwr.c
> +++ b/drivers/vfio/pci/vfio_pci_rdwr.c
> @@ -38,7 +38,7 @@
> #define vfio_iowrite8 iowrite8
>
> #define VFIO_IOWRITE(size) \
> -static int vfio_pci_iowrite##size(struct vfio_pci_core_device *vdev, \
> +int vfio_pci_iowrite##size(struct vfio_pci_core_device *vdev, \
> bool test_mem, u##size val, void __iomem *io) \
> { \
> if (test_mem) { \
> @@ -55,7 +55,8 @@ static int vfio_pci_iowrite##size(struct vfio_pci_core_device *vdev, \
> up_read(&vdev->memory_lock); \
> \
> return 0; \
> -}
> +} \
> +EXPORT_SYMBOL_GPL(vfio_pci_iowrite##size);
>
> VFIO_IOWRITE(8)
> VFIO_IOWRITE(16)
> @@ -65,7 +66,7 @@ VFIO_IOWRITE(64)
> #endif
>
> #define VFIO_IOREAD(size) \
> -static int vfio_pci_ioread##size(struct vfio_pci_core_device *vdev, \
> +int vfio_pci_ioread##size(struct vfio_pci_core_device *vdev, \
> bool test_mem, u##size *val, void __iomem *io) \
> { \
> if (test_mem) { \
> @@ -82,7 +83,8 @@ static int vfio_pci_ioread##size(struct vfio_pci_core_device *vdev, \
> up_read(&vdev->memory_lock); \
> \
> return 0; \
> -}
> +} \
> +EXPORT_SYMBOL_GPL(vfio_pci_ioread##size);
>
> VFIO_IOREAD(8)
> VFIO_IOREAD(16)
> diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
> index 67ac58e20e1d..22c915317788 100644
> --- a/include/linux/vfio_pci_core.h
> +++ b/include/linux/vfio_pci_core.h
> @@ -131,4 +131,23 @@ int vfio_pci_core_setup_barmap(struct vfio_pci_core_device *vdev, int bar);
> pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
> pci_channel_state_t state);
>
> +#define VFIO_IOWRITE_DECLATION(size) \
> +int vfio_pci_iowrite##size(struct vfio_pci_core_device *vdev, \
> + bool test_mem, u##size val, void __iomem *io);
> +
> +VFIO_IOWRITE_DECLATION(8)
> +VFIO_IOWRITE_DECLATION(16)
> +VFIO_IOWRITE_DECLATION(32)
> +#ifdef iowrite64
> +VFIO_IOWRITE_DECLATION(64)
> +#endif
> +
> +#define VFIO_IOREAD_DECLATION(size) \
> +int vfio_pci_ioread##size(struct vfio_pci_core_device *vdev, \
> + bool test_mem, u##size *val, void __iomem *io);
> +
> +VFIO_IOREAD_DECLATION(8)
> +VFIO_IOREAD_DECLATION(16)
> +VFIO_IOREAD_DECLATION(32)
> +
> #endif /* VFIO_PCI_CORE_H */