Re: [PATCH v5 06/10] vfio-iommufd: Add helper to retrieve iommufd_ctx and devid for vfio_device

[Alex Williamson <alex.williamson@redhat.com>]

On Sat, 13 May 2023 06:21:32 -0700
Yi Liu <yi.l.liu@intel.com> wrote:

> This is needed by the vfio-pci driver to report affected devices in the
> hot reset for a given device.
> 
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
>  drivers/iommu/iommufd/device.c | 24 ++++++++++++++++++++++++
>  drivers/vfio/iommufd.c         | 20 ++++++++++++++++++++
>  include/linux/iommufd.h        |  6 ++++++
>  include/linux/vfio.h           | 14 ++++++++++++++
>  4 files changed, 64 insertions(+)
> 
> diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
> index 4f9b2142274c..81466b97023f 100644
> --- a/drivers/iommu/iommufd/device.c
> +++ b/drivers/iommu/iommufd/device.c
> @@ -116,6 +116,18 @@ void iommufd_device_unbind(struct iommufd_device *idev)
>  }
>  EXPORT_SYMBOL_NS_GPL(iommufd_device_unbind, IOMMUFD);
>  
> +struct iommufd_ctx *iommufd_device_to_ictx(struct iommufd_device *idev)
> +{
> +	return idev->ictx;
> +}
> +EXPORT_SYMBOL_NS_GPL(iommufd_device_to_ictx, IOMMUFD);
> +
> +u32 iommufd_device_to_id(struct iommufd_device *idev)
> +{
> +	return idev->obj.id;
> +}
> +EXPORT_SYMBOL_NS_GPL(iommufd_device_to_id, IOMMUFD);
> +
>  static int iommufd_device_setup_msi(struct iommufd_device *idev,
>  				    struct iommufd_hw_pagetable *hwpt,
>  				    phys_addr_t sw_msi_start)
> @@ -463,6 +475,18 @@ void iommufd_access_destroy(struct iommufd_access *access)
>  }
>  EXPORT_SYMBOL_NS_GPL(iommufd_access_destroy, IOMMUFD);
>  
> +struct iommufd_ctx *iommufd_access_to_ictx(struct iommufd_access *access)
> +{
> +	return access->ictx;
> +}
> +EXPORT_SYMBOL_NS_GPL(iommufd_access_to_ictx, IOMMUFD);
> +
> +u32 iommufd_access_to_id(struct iommufd_access *access)
> +{
> +	return access->obj.id;
> +}
> +EXPORT_SYMBOL_NS_GPL(iommufd_access_to_id, IOMMUFD);
> +
>  int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id)
>  {
>  	struct iommufd_ioas *new_ioas;
> diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
> index c1379e826052..a18e920be164 100644
> --- a/drivers/vfio/iommufd.c
> +++ b/drivers/vfio/iommufd.c
> @@ -105,6 +105,26 @@ void vfio_iommufd_unbind(struct vfio_device *vdev)
>  		vdev->ops->unbind_iommufd(vdev);
>  }
>  
> +struct iommufd_ctx *vfio_iommufd_physical_ictx(struct vfio_device *vdev)
> +{
> +	if (vdev->iommufd_device)
> +		return iommufd_device_to_ictx(vdev->iommufd_device);
> +	if (vdev->noiommu_access)
> +		return iommufd_access_to_ictx(vdev->noiommu_access);
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(vfio_iommufd_physical_ictx);
> +
> +int vfio_iommufd_physical_devid(struct vfio_device *vdev)
> +{
> +	if (vdev->iommufd_device)
> +		return iommufd_device_to_id(vdev->iommufd_device);
> +	if (vdev->noiommu_access)
> +		return iommufd_access_to_id(vdev->noiommu_access);
> +	return -EINVAL;
> +}
> +EXPORT_SYMBOL_GPL(vfio_iommufd_physical_devid);

I think these exemplify that it would be better if both emulated and
noiommu use the same iommufd_access pointer.  Thanks,

Alex

> +
>  /*
>   * The physical standard ops mean that the iommufd_device is bound to the
>   * physical device vdev->dev that was provided to vfio_init_group_dev(). Drivers
> diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
> index 1129a36a74c4..68cd65274e28 100644
> --- a/include/linux/iommufd.h
> +++ b/include/linux/iommufd.h
> @@ -24,6 +24,9 @@ void iommufd_device_unbind(struct iommufd_device *idev);
>  int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id);
>  void iommufd_device_detach(struct iommufd_device *idev);
>  
> +struct iommufd_ctx *iommufd_device_to_ictx(struct iommufd_device *idev);
> +u32 iommufd_device_to_id(struct iommufd_device *idev);
> +
>  struct iommufd_access_ops {
>  	u8 needs_pin_pages : 1;
>  	void (*unmap)(void *data, unsigned long iova, unsigned long length);
> @@ -45,6 +48,9 @@ iommufd_access_create(struct iommufd_ctx *ictx,
>  void iommufd_access_destroy(struct iommufd_access *access);
>  int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id);
>  
> +struct iommufd_ctx *iommufd_access_to_ictx(struct iommufd_access *access);
> +u32 iommufd_access_to_id(struct iommufd_access *access);
> +
>  void iommufd_ctx_get(struct iommufd_ctx *ictx);
>  
>  #if IS_ENABLED(CONFIG_IOMMUFD)
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index a61130bc06a2..fcbe084b18c8 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -115,6 +115,8 @@ struct vfio_device_ops {
>  };
>  
>  #if IS_ENABLED(CONFIG_IOMMUFD)
> +struct iommufd_ctx *vfio_iommufd_physical_ictx(struct vfio_device *vdev);
> +int vfio_iommufd_physical_devid(struct vfio_device *vdev);
>  int vfio_iommufd_physical_bind(struct vfio_device *vdev,
>  			       struct iommufd_ctx *ictx, u32 *out_device_id);
>  void vfio_iommufd_physical_unbind(struct vfio_device *vdev);
> @@ -124,6 +126,18 @@ int vfio_iommufd_emulated_bind(struct vfio_device *vdev,
>  void vfio_iommufd_emulated_unbind(struct vfio_device *vdev);
>  int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id);
>  #else
> +static inline struct iommufd_ctx *
> +vfio_iommufd_physical_ictx(struct vfio_device *vdev)
> +{
> +	return NULL;
> +}
> +
> +static inline int
> +vfio_iommufd_physical_devid(struct vfio_device *vdev)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
>  #define vfio_iommufd_physical_bind                                      \
>  	((int (*)(struct vfio_device *vdev, struct iommufd_ctx *ictx,   \
>  		  u32 *out_device_id)) NULL)