Re: [RFC v3 00/27] lib: Rust implementation of SPDM

[Dan Williams (nvidia)]

Alistair Francis wrote:
> On Fri, Apr 17, 2026 at 2:34 PM Lukas Wunner <lukas@xxxxxxxxx> wrote:
> >
> > On Thu, Apr 16, 2026 at 07:35:44PM -0700, Dan Williams wrote:
> > > Later in the thread I proposed an alternative that instead of supporting
> > > 2 flavors of uapi through "authenticated", instead implement CMA as
> > > another TSM driver [1].
> > >
> > > [1]: http://lore.kernel.org/69976d7d39c60_2f4a1009@dwillia2-mobl4.notmuch
> >
> > Please keep in mind though that CMA is just the PCIe adaption of SPDM,
> > SPDM is not only needed for PCIe but also SCSI, ATA and possibly others
> > and so implementing CMA as a TSM driver must not preclude use of SPDM
> > in other subsystems.
> 
> That should be fine as the current SPDM implementation is
> self-contained, but thanks for raising that.
> 
> Just to make sure I'm not going in the wrong direction, the idea would
> be to build on
> 
> https://lore.kernel.org/all/20260303000207.1836586-9-dan.j.williams@xxxxxxxxx/
> 
> and add something like this?
> 
> ```
> static const struct pci_tsm_ops pci_cma_tsm_ops = {
>     .link_ops = {
>         .probe        = pci_cma_tsm_probe,
>         .remove        = pci_cma_tsm_remove,
>         .connect    = pci_cma_tsm_connect,
>         .disconnect    = pci_cma_tsm_disconnect,
>     },
>     .refresh_evidence    = pci_cma_tsm_refresh,
> };
> ```
> 
> The docs for `struct pci_tsm_ops` seem pretty TSM specific, so I just
> wanted to double check before going ahead.
> 
> That means all of the netlink stuff in this series can be dropped and
> we just use the TSM netlink (which might need some adjustments then,
> I'll have to double check)

Right, the above looks what I was expecting.

As for netlink, Lukas is right about non CMA use cases. The netlink
interface will either need to move to be a generic "device evidence"
facility, not scoped to PCI/TSM, or itself become a library that
different producers of SPDM material can use to export it to userspace.