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There are two components to establishing an encrypted link, provisioning
the stream in Partner Port config-space, and programming the keys into
the link layer via IDE_KM (IDE Key Management). This new library,
drivers/pci/ide.c, enables the former. IDE_KM, via a TSM low-level
driver, is saved for later.
With the platform TSM implementations of SEV-TIO and TDX Connect in mind
this library abstracts small differences in those implementations. For
example, TDX Connect handles Root Port register setup while SEV-TIO
expects System Software to update the Root Port registers. This is the
rationale for fine-grained 'setup' + 'enable' verbs.
The other design detail for TSM-coordinated IDE establishment is that
the TSM may manage allocation of Stream IDs, this is why the Stream ID
value is passed in to pci_ide_stream_setup().
The flow is:
pci_ide_stream_alloc():
Allocate a Selective IDE Stream Register Block in each Partner Port
(Endpoint + Root Port), and reserve a host bridge / platform stream
slot. Gather Partner Port specific stream settings like Requester ID.
pci_ide_stream_register():
Publish the stream in sysfs after allocating a Stream ID. In the TSM
case the TSM allocates the Stream ID for the Partner Port pair.
pci_ide_stream_setup():
Program the stream settings to a Partner Port. Caller is responsible
for optionally calling this for the Root Port as well if the TSM
implementation requires it.
pci_ide_stream_enable():
Enable the stream after IDE_KM.
In support of system administrators auditing where platform, Root Port,
and Endpoint IDE stream resources are being spent, the allocated stream
is reflected as a symlink from the host bridge to the endpoint with the
name:
stream%d.%d.%d
Where the tuple of integers reflects the allocated platform, Root Port,
and Endpoint stream index (Selective IDE Stream Register Block) values.
Thanks to Wu Hao for a draft implementation of this infrastructure.
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Samuel Ortiz <sameo@rivosinc.com>
Co-developed-by: Alexey Kardashevskiy <aik@amd.com>
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Co-developed-by: Xu Yilun <yilun.xu@linux.intel.com>
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/20251031212902.2256310-8-dan.j.williams@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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.