[PATCH kernel 0/9] PCI/TSM: coco/sev-guest: Implement SEV-TIO PCIe TDISP (phase2)

[Alexey Kardashevskiy]

Here are some patches to continue enabling SEV-TIO on AMD.

SEV-TIO allows guests to establish trust in a device that supports TEE
Device Interface Security Protocol (TDISP, defined in PCIe r6.0+) and
then interact with the device via private memory.

In order to streamline upstreaming process, a common TSM infrastructure
is being developed in collaboration with Intel+ARM+RiscV. There is
Documentation/driver-api/pci/tsm.rst with proposed phases:
1. IDE: encrypt PCI, host only
2. TDISP: lock + accept flow, host and guest, interface report
3. Enable secure MMIO + DMA: IOMMUFD, KVM changes
4. Device attestation: certificates, measurements

This is phase2 == basic guest support allowing TDISP CONFIG_LOCKED and RUN states, and unlocking as well.

Acronyms:
TEE - Trusted Execution Environments, a concept of managing trust between the host and devices
TSM - TEE Security Manager (TSM), an entity which ensures security on the host
PSP - AMD platform secure processor (also "ASP", "AMD-SP"), acts as TSM on AMD.
SEV TIO - the TIO protocol implemented by the PSP and used by the host, extension to SEV-SNP
GHCB - guest/host communication block - a protocol for guest-to-host communication via a shared page
TDISP - TEE Device Interface Security Protocol (PCIe).



Flow:
- Boot guest OS, load sev-guest.ko which registers itself as a TSM
- PCI TSM creates sysfs nodes under "tsm" subdirectory in for all
  TDISP-capable devices
  - lock the device via:
  	echo tsm0 > "/sys/bus/pci/devices/0000:01:00.0/tsm/lock"
  - accept the device via:
  	echo 1 > "/sys/bus/pci/devices/0000:01:00.0/tsm/accept"
  - load the device driver:
  	- DMA to encrypted memory should work right away
	- MMIO regions reported in TDISP interface report will be mapped as encrypted


Since one of my test devices does not use private MMIO for the main function,
there is 9/9 which allows https://github.com/billfarrow/pcimem.git mapping MMIO as private.


The previous conversation is here:
https://lore.kernel.org/r/20250218111017.491719-1-aik@xxxxxxx 

This is based on sha1
4fe8662d1a9c Dan Williams PCI/TSM: Documentation: Add Maturity Map
from
https://git.kernel.org/pub/scm/linux/kernel/git/devsec/tsm.git/log/?h=staging
and 3 cherrypicks on top, please find the exact tree at:
https://github.com/AMDESE/linux-kvm/commits/tsm-staging

The host support is pushed here:
https://github.com/AMDESE/linux-kvm/commits/tsm

The SEV TIO spec:
https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/58271.pdf

Individual patches have extra "---" comments (could have been "RFC"?)

Please comment. Thanks.

ps: quite a cc list from get_maintainers.pl.



Alexey Kardashevskiy (9):
  pci/tsm: Add TDISP report blob and helpers to parse it
  pci/tsm: Add tsm_tdi_status
  coco/sev-guest: Allow multiple source files in the driver
  dma/swiotlb: Stop forcing SWIOTLB for TDISP devices
  x86/mm: Stop forcing decrypted page state for TDISP devices
  x86/dma-direct: Stop changing encrypted page state for TDISP devices
  coco/sev-guest: Implement the guest support for SEV TIO (phase2)
  RFC: PCI: Avoid needless touching of Command register
  pci: Allow encrypted MMIO mapping via sysfs

 arch/x86/Kconfig                        |   1 +
 drivers/virt/coco/sev-guest/Kconfig     |   1 +
 drivers/virt/coco/sev-guest/Makefile    |   6 +-
 arch/x86/include/asm/dma-direct.h       |  39 ++
 arch/x86/include/asm/sev-common.h       |   1 +
 arch/x86/include/asm/sev.h              |  13 +
 arch/x86/include/uapi/asm/svm.h         |  13 +
 drivers/virt/coco/sev-guest/sev-guest.h |  20 +
 include/linux/pci-tsm.h                 | 110 +++
 include/linux/pci.h                     |   2 +-
 include/linux/psp-sev.h                 |  31 +
 include/linux/swiotlb.h                 |   9 +
 include/uapi/linux/sev-guest.h          |  43 ++
 arch/x86/coco/sev/core.c                |  53 ++
 arch/x86/mm/mem_encrypt.c               |   5 +-
 drivers/pci/mmap.c                      |  11 +-
 drivers/pci/pci-sysfs.c                 |  27 +-
 drivers/pci/probe.c                     |   5 +
 drivers/pci/proc.c                      |   2 +-
 drivers/pci/quirks.c                    |   9 +
 drivers/virt/coco/sev-guest/sev-guest.c |  23 +-
 drivers/virt/coco/sev-guest/tio.c       | 707 ++++++++++++++++++++
 drivers/virt/coco/tsm-core.c            |  19 +
 23 files changed, 1129 insertions(+), 21 deletions(-)
 create mode 100644 arch/x86/include/asm/dma-direct.h
 create mode 100644 drivers/virt/coco/sev-guest/sev-guest.h
 create mode 100644 drivers/virt/coco/sev-guest/tio.c

-- 
2.52.0