Re: [RFC PATCH 3/4] PCI/DOE: Add DOE mailbox support for endpoint functions

[Aksh Garg]

Mani, Alistair

On 04/03/26 19:48, Manivannan Sadhasivam wrote:
> On Wed, Feb 18, 2026 at 02:28:23PM +1000, Alistair Francis wrote:
> > On 13/2/26 22:36, Aksh Garg wrote:
> > > From: Aksh Garg <a-garg7@xxxxxx>
> > >
> > > DOE (Data Object Exchange) is a standard PCIe extended capability
> > > feature introduced in the Data Object Exchange (DOE) ECN for
> > > PCIe r5.0. It provides a communication mechanism primarily used for
> > > implementing PCIe security features such as device authentication, and
> > > secure link establishment. Think of DOE as a sophisticated mailbox
> > > system built into PCIe. The root complex can send structured requests
> > > to the endpoint device through DOE mailboxes, and the endpoint device
> > > responds with appropriate data.
> > >
> > > Add the DOE support for PCIe endpoint devices, enabling endpoint
> > > functions to process the DOE requests from the host. The implementation
> > > provides framework APIs for controller drivers to register mailboxes,
> > > protocol handler registration for different DOE data object types, and
> > > request processing with workqueues ensuring sequential handling per
> > > mailbox. The Discovery protocol is handled internally by the DOE core.
> > >
> > > This implementation complements the existing DOE implementation for
> > > root complex in drivers/pci/doe.c.
> >
> > This looks good to me!
> >
> > I would love to see a handler implementation and integration with a driver
> > as well.
> >
> > For SPDM the handler could even be in userspace
>
> +1. We should not be introducing dead APIs.
>
> - Mani

I am planning to remove the register/unregister protocol APIs, and add a
static array of 'struct pci_doe_protocol' instead of a dynamic xarray.
By this, we would not be relying on someone to call the register
protocol on behalf of a library.
Whenever a new library comes up for DOE protocol, the library would have
the handler function, and the static array simply needs to populated
with this handler function in doe-ep.c

Please share your thoughts on this approach.

> > Alistair
> >
> > > Co-developed-by: Siddharth Vadapalli <s-vadapalli@xxxxxx>
> > > Signed-off-by: Siddharth Vadapalli <s-vadapalli@xxxxxx>
> > > Signed-off-by: Aksh Garg <a-garg7@xxxxxx>
> > > ---