Re: [PATCH v4 09/10] PCI/TSM: Report active IDE streams

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Thu, 17 Jul 2025 11:33:57 -0700
Dan Williams <dan.j.williams@intel.com> wrote:

> Given that the platform TSM owns IDE Stream ID allocation, report the
> active streams via the TSM class device. Establish a symlink from the
> class device to the PCI endpoint device consuming the stream, named by
> the Stream ID.
> 
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Trivial stuff only
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

> ---
>  Documentation/ABI/testing/sysfs-class-tsm | 10 ++++++++
>  drivers/pci/ide.c                         |  4 ++++
>  drivers/virt/coco/tsm-core.c              | 28 +++++++++++++++++++++++
>  include/linux/pci-ide.h                   |  2 ++
>  include/linux/tsm.h                       |  4 ++++
>  5 files changed, 48 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-tsm b/Documentation/ABI/testing/sysfs-class-tsm
> index 2949468deaf7..6fc1a5ac6da1 100644
> --- a/Documentation/ABI/testing/sysfs-class-tsm
> +++ b/Documentation/ABI/testing/sysfs-class-tsm
> @@ -7,3 +7,13 @@ Description:
>  		signals when the PCI layer is able to support establishment of
>  		link encryption and other device-security features coordinated
>  		through a platform tsm.
> +
> +What:		/sys/class/tsm/tsmN/streamH.R.E
> +Contact:	linux-pci@vger.kernel.org
> +Description:
> +		(RO) When a host bridge has established a secure connection via
> +		the platform TSM, symlink appears. The primary function of this
> +		is have a system global review of TSM resource consumption
> +		across host bridges. The link points to the endpoint PCI device
> +		and matches the same link published by the host bridge. See
> +		Documentation/ABI/testing/sysfs-devices-pci-host-bridge.

> diff --git a/drivers/virt/coco/tsm-core.c b/drivers/virt/coco/tsm-core.c
> index 093824dc68dd..b0ef9089e0f2 100644
> --- a/drivers/virt/coco/tsm-core.c
> +++ b/drivers/virt/coco/tsm-core.c

> +/* must be invoked between tsm_register / tsm_unregister */
> +int tsm_ide_stream_register(struct pci_ide *ide)
> +{
> +	struct pci_dev *pdev = ide->pdev;
> +	struct pci_tsm *tsm = pdev->tsm;
> +	struct tsm_dev *tsm_dev = tsm->ops->owner;
> +	int rc;
> +
> +	rc = sysfs_create_link(&tsm_dev->dev.kobj, &pdev->dev.kobj,
> +			       ide->name);

Fits on one line under 80 chars (just)

> +	if (rc == 0)
> +		ide->tsm_dev = tsm_dev;

I'd prefer 

	if (rc)
		return rc;

	ide->tsm_dev = tsm_dev;

	return 0;

but don't care that much.

> +	return rc;
> +}
> +EXPORT_SYMBOL_GPL(tsm_ide_stream_register);
> +
> +void tsm_ide_stream_unregister(struct pci_ide *ide)
> +{
> +	struct tsm_dev *tsm_dev = ide->tsm_dev;
> +
> +	sysfs_remove_link(&tsm_dev->dev.kobj, ide->name);
> +	ide->tsm_dev = NULL;
> +}
> +EXPORT_SYMBOL_GPL(tsm_ide_stream_unregister);

> diff --git a/include/linux/tsm.h b/include/linux/tsm.h
> index ce95589a5d5b..4eba45a754ec 100644
> --- a/include/linux/tsm.h
> +++ b/include/linux/tsm.h
> @@ -120,4 +120,8 @@ const char *tsm_name(const struct tsm_dev *tsm_dev);
>  struct tsm_dev *find_tsm_dev(int id);
>  const struct pci_tsm_ops *tsm_pci_ops(const struct tsm_dev *tsm_dev);
>  const struct attribute_group *tsm_pci_group(const struct tsm_dev *tsm_dev);
> +struct pci_dev;

Not used.

> +struct pci_ide;
> +int tsm_ide_stream_register(struct pci_ide *ide);
> +void tsm_ide_stream_unregister(struct pci_ide *ide);
>  #endif /* __TSM_H */