Dan Williams c316c75d57 PCI/TSM: Add pci_tsm_guest_req() for managing TDIs
A PCIe device function interface assigned to a TVM is a TEE Device
Interface (TDI). A TDI instantiated by pci_tsm_bind() needs additional
steps taken by the TVM to be accepted into the TVM's Trusted Compute
Boundary (TCB) and transitioned to the RUN state.

pci_tsm_guest_req() is a channel for the guest to request TDISP collateral,
like Device Interface Reports, and effect TDISP state changes, like
LOCKED->RUN transititions. Similar to IDE establishment and pci_tsm_bind(),
these are long running operations involving SPDM message passing via the
DOE mailbox.

The path for a TVM to invoke pci_tsm_guest_req() is:
* TSM triggers exit via guest-to-host-interface ABI (implementation specific)
* VMM invokes handler (KVM handle_exit() -> userspace io)
* handler issues request (userspace io handler -> ioctl() ->
  pci_tsm_guest_req())
* handler supplies response
* VMM posts response, notifies/re-enters TVM

This path is purely a transport for messages from TVM to platform TSM. By
design the host kernel does not and must not care about the content of
these messages. I.e. the host kernel is not in the TCB of the TVM.

As this is an opaque passthrough interface, similar to fwctl, the kernel
requires that implementations stay within the bounds defined by 'enum
pci_tsm_req_scope'. Violation of those expectations likely has market and
regulatory consequences. Out of scope requests are blocked by default.

Co-developed-by: Xu Yilun <yilun.xu@linux.intel.com>
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/20251113021446.436830-8-dan.j.williams@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2025-11-14 15:06:57 -08:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2025-11-02 11:28:02 -08:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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