Re: [RFC PATCH 19/30] vfio/pci: Add TSM TDI bind/unbind IOCTLs for TEE-IO support

[Aneesh Kumar K.V <aneesh.kumar@kernel.org>]

Xu Yilun <yilun.xu@linux.intel.com> writes:

> Add new IOCTLs to do TSM based TDI bind/unbind. These IOCTLs are
> expected to be called by userspace when CoCo VM issues TDI bind/unbind
> command to VMM. Specifically for TDX Connect, these commands are some
> secure Hypervisor call named GHCI (Guest-Hypervisor Communication
> Interface).
>
> The TSM TDI bind/unbind operations are expected to be initiated by a
> running CoCo VM, which already have the legacy assigned device in place.
> The TSM bind operation is to request VMM make all secure configurations
> to support device work as a TDI, and then issue TDISP messages to move
> the TDI to CONFIG_LOCKED or RUN state, waiting for guest's attestation.
>
> Do TSM Unbind before vfio_pci_core_disable(), otherwise will lead
> device to TDISP ERROR state.
>

Any reason these need to be a vfio ioctl instead of iommufd ioctl?
For ex: https://lore.kernel.org/all/20250529133757.462088-3-aneesh.kumar@kernel.org/

>
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Wu Hao <hao.wu@intel.com>
> Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
> ---
>  drivers/vfio/iommufd.c           | 22 ++++++++++
>  drivers/vfio/pci/vfio_pci_core.c | 74 ++++++++++++++++++++++++++++++++
>  include/linux/vfio.h             |  7 +++
>  include/linux/vfio_pci_core.h    |  1 +
>  include/uapi/linux/vfio.h        | 42 ++++++++++++++++++
>  5 files changed, 146 insertions(+)
>
> diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
> index 3441d24538a8..33fd20ffaeee 100644
> --- a/drivers/vfio/iommufd.c
> +++ b/drivers/vfio/iommufd.c
> @@ -297,3 +297,25 @@ void vfio_iommufd_emulated_detach_ioas(struct vfio_device *vdev)
>  	vdev->iommufd_attached = false;
>  }
>  EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_detach_ioas);
> +
> +int vfio_iommufd_tsm_bind(struct vfio_device *vdev, u32 vdevice_id)
> +{
> +	lockdep_assert_held(&vdev->dev_set->lock);
> +
> +	if (WARN_ON(!vdev->iommufd_device))
> +		return -EINVAL;
> +
> +	return iommufd_device_tsm_bind(vdev->iommufd_device, vdevice_id);
> +}
> +EXPORT_SYMBOL_GPL(vfio_iommufd_tsm_bind);
> +
> +void vfio_iommufd_tsm_unbind(struct vfio_device *vdev)
> +{
> +	lockdep_assert_held(&vdev->dev_set->lock);
> +
> +	if (WARN_ON(!vdev->iommufd_device))
> +		return;
> +
> +	iommufd_device_tsm_unbind(vdev->iommufd_device);
> +}
> +EXPORT_SYMBOL_GPL(vfio_iommufd_tsm_unbind);
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 116964057b0b..92544e54c9c3 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -692,6 +692,13 @@ void vfio_pci_core_close_device(struct vfio_device *core_vdev)
>  #if IS_ENABLED(CONFIG_EEH)
>  	eeh_dev_release(vdev->pdev);
>  #endif
> +
> +	if (vdev->is_tsm_bound) {
> +		vfio_iommufd_tsm_unbind(&vdev->vdev);
> +		pci_release_regions(vdev->pdev);
> +		vdev->is_tsm_bound = false;
> +	}
> +
>  	vfio_pci_core_disable(vdev);
>  
>  	vfio_pci_dma_buf_cleanup(vdev);
> @@ -1447,6 +1454,69 @@ static int vfio_pci_ioctl_ioeventfd(struct vfio_pci_core_device *vdev,
>  				  ioeventfd.fd);
>  }
>  
> +static int vfio_pci_ioctl_tsm_bind(struct vfio_pci_core_device *vdev,
> +				   void __user *arg)
> +{
> +	unsigned long minsz = offsetofend(struct vfio_pci_tsm_bind, vdevice_id);
> +	struct vfio_pci_tsm_bind tsm_bind;
> +	struct pci_dev *pdev = vdev->pdev;
> +	int ret;
> +
> +	if (copy_from_user(&tsm_bind, arg, minsz))
> +		return -EFAULT;
> +
> +	if (tsm_bind.argsz < minsz || tsm_bind.flags)
> +		return -EINVAL;
> +
> +	mutex_lock(&vdev->vdev.dev_set->lock);
> +
> +	/* To ensure no host side MMIO access is possible */
> +	ret = pci_request_regions_exclusive(pdev, "vfio-pci-tsm");
> +	if (ret)
> +		goto out_unlock;
>

This should be part of pci_tsm_bind() ? 

> +
> +	ret = vfio_iommufd_tsm_bind(&vdev->vdev, tsm_bind.vdevice_id);
> +	if (ret)
> +		goto out_release_region;
> +
> +	vdev->is_tsm_bound = true;
> +	mutex_unlock(&vdev->vdev.dev_set->lock);
> +
> +	return 0;
> +
> +out_release_region:
> +	pci_release_regions(pdev);
> +out_unlock:
> +	mutex_unlock(&vdev->vdev.dev_set->lock);
> +	return ret;
> +}
> +
> +static int vfio_pci_ioctl_tsm_unbind(struct vfio_pci_core_device *vdev,
> +				     void __user *arg)
> +{
> +	unsigned long minsz = offsetofend(struct vfio_pci_tsm_unbind, flags);
> +	struct vfio_pci_tsm_unbind tsm_unbind;
> +	struct pci_dev *pdev = vdev->pdev;
> +
> +	if (copy_from_user(&tsm_unbind, arg, minsz))
> +		return -EFAULT;
> +
> +	if (tsm_unbind.argsz < minsz || tsm_unbind.flags)
> +		return -EINVAL;
> +
> +	mutex_lock(&vdev->vdev.dev_set->lock);
> +
> +	if (!vdev->is_tsm_bound)
> +		return 0;
> +
> +	vfio_iommufd_tsm_unbind(&vdev->vdev);
> +	pci_release_regions(pdev);
> +	vdev->is_tsm_bound = false;
> +	mutex_unlock(&vdev->vdev.dev_set->lock);
> +
> +	return 0;
> +}
> +


-aneesh