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Pull PCIe Link Encryption and Device Authentication from Dan Williams:
"New PCI infrastructure and one architecture implementation for PCIe
link encryption establishment via platform firmware services.
This work is the result of multiple vendors coming to consensus on
some core infrastructure (thanks Alexey, Yilun, and Aneesh!), and
three vendor implementations, although only one is included in this
pull. The PCI core changes have an ack from Bjorn, the crypto/ccp/
changes have an ack from Tom, and the iommu/amd/ changes have an ack
from Joerg.
PCIe link encryption is made possible by the soup of acronyms
mentioned in the shortlog below. Link Integrity and Data Encryption
(IDE) is a protocol for installing keys in the transmitter and
receiver at each end of a link. That protocol is transported over Data
Object Exchange (DOE) mailboxes using PCI configuration requests.
The aspect that makes this a "platform firmware service" is that the
key provisioning and protocol is coordinated through a Trusted
Execution Envrionment (TEE) Security Manager (TSM). That is either
firmware running in a coprocessor (AMD SEV-TIO), or quasi-hypervisor
software (Intel TDX Connect / ARM CCA) running in a protected CPU
mode.
Now, the only reason to ask a TSM to run this protocol and install the
keys rather than have a Linux driver do the same is so that later, a
confidential VM can ask the TSM directly "can you certify this
device?".
That precludes host Linux from provisioning its own keys, because host
Linux is outside the trust domain for the VM. It also turns out that
all architectures, save for one, do not publish a mechanism for an OS
to establish keys in the root port. So "TSM-established link
encryption" is the only cross-architecture path for this capability
for the foreseeable future.
This unblocks the other arch implementations to follow in v6.20/v7.0,
once they clear some other dependencies, and it unblocks the next
phase of work to implement the end-to-end flow of confidential device
assignment. The PCIe specification calls this end-to-end flow Trusted
Execution Environment (TEE) Device Interface Security Protocol
(TDISP).
In the meantime, Linux gets a link encryption facility which has
practical benefits along the same lines as memory encryption. It
authenticates devices via certificates and may protect against
interposer attacks trying to capture clear-text PCIe traffic.
Summary:
- Introduce the PCI/TSM core for the coordination of device
authentication, link encryption and establishment (IDE), and later
management of the device security operational states (TDISP).
Notify the new TSM core layer of PCI device arrival and departure
- Add a low level TSM driver for the link encryption establishment
capabilities of the AMD SEV-TIO architecture
- Add a library of helpers TSM drivers to use for IDE establishment
and the DOE transport
- Add skeleton support for 'bind' and 'guest_request' operations in
support of TDISP"
* tag 'tsm-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/devsec/tsm: (23 commits)
crypto/ccp: Fix CONFIG_PCI=n build
virt: Fix Kconfig warning when selecting TSM without VIRT_DRIVERS
crypto/ccp: Implement SEV-TIO PCIe IDE (phase1)
iommu/amd: Report SEV-TIO support
psp-sev: Assign numbers to all status codes and add new
ccp: Make snp_reclaim_pages and __sev_do_cmd_locked public
PCI/TSM: Add 'dsm' and 'bound' attributes for dependent functions
PCI/TSM: Add pci_tsm_guest_req() for managing TDIs
PCI/TSM: Add pci_tsm_bind() helper for instantiating TDIs
PCI/IDE: Initialize an ID for all IDE streams
PCI/IDE: Add Address Association Register setup for downstream MMIO
resource: Introduce resource_assigned() for discerning active resources
PCI/TSM: Drop stub for pci_tsm_doe_transfer()
drivers/virt: Drop VIRT_DRIVERS build dependency
PCI/TSM: Report active IDE streams
PCI/IDE: Report available IDE streams
PCI/IDE: Add IDE establishment helpers
PCI: Establish document for PCI host bridge sysfs attributes
PCI: Add PCIe Device 3 Extended Capability enumeration
PCI/TSM: Establish Secure Sessions and Link Encryption
...