Jonathan Cameron wrote:
> On Thu, 15 May 2025 22:47:29 -0700
> Dan Williams <dan.j.williams@xxxxxxxxx> 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@xxxxxxxxx>
> > ---
> > Documentation/ABI/testing/sysfs-class-tsm | 10 ++++++++++
> > drivers/virt/coco/host/tsm-core.c | 17 +++++++++++++++++
> > include/linux/tsm.h | 4 ++++
> > 3 files changed, 31 insertions(+)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-class-tsm b/Documentation/ABI/testing/sysfs-class-tsm
> > index 7503f04a9eb9..75ee2b9bc555 100644
> > --- a/Documentation/ABI/testing/sysfs-class-tsm
> > +++ b/Documentation/ABI/testing/sysfs-class-tsm
> > @@ -8,3 +8,13 @@ Description:
> > signals when the PCI layer is able to support establishment of
> > link encryption and other device-security features coordinated
> > through the platform tsm.
> > +
> > +What: /sys/class/tsm/tsm0/streamN:DDDD:BB:DD:F
> > +Date: December, 2024
> > +Contact: linux-pci@xxxxxxxxxxxxxxx
> > +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
> > + at domain:DDDD bus:BB device:DD function:F.
>
> Do we need the name to link to include the sbdf? Maybe just streamN
> is enough. It's a little fiddly to get the spdf from where that goes, but not
> that challenging.
>
> For user ls -lf /sys/class/tsm/tsm0/* should work for instance.
I had the target PCI device name in the link name before the rewrite to
name the stream with the tuple of {host_bridge_stream_id,
root_port_stream_id, endpoint_stream_id}. With that in place the stream
name is disambiguated and the PCI device name can be dropped.
> I don't care strongly about this. Maybe one for Bjorn.
The shorter name is less complicated.
