Subject: [RFC PATCH v4 00/11] coco/TSM: Arm CCA guest TDISP lock/accept flow with verification and DMA enable

From: "Aneesh Kumar K.V (Arm)" <[email-masked]>
Date: Mon, 27 Apr 2026 13:57:54 +0530

This patch series implements the TSM ->lock(), ->unlock(), and ->accept()
callbacks required for the TDISP setup with Arm CCA as per as per the RMM
2.0bet1 specification [1].

The series adds the guest-side DA plumbing needed to transition a device
through TDI LOCK and RUN states, verify host-provided evidence against
RMM-provided digests, validate interface-report MMIO mappings, and enable
DMA only after attestation succeeds.

At a high level, the series includes:
- guest TSM callback registration and lock/unlock/accept hooks
- RHI DA helper support for TDI state transitions and object refresh
- host-cached DA object fetch APIs in guest
- RSI_VDEV_GET_INFO digest verification of certificate/VCA/report/measurement
- mapping validation for interface-report ranges and teardown on unlock
- DMA behavior updates for accepted devices (including swiotlb restrictions)
- vdev DMA enable after successful attestation

The series builds upon the TSM framework patches posted at [2]. A git repository
containing all the related changes is available at [3].

Testing / Usage

echo ${DEVICE} > /sys/bus/pci/devices/${DEVICE}/driver/unbind

To transition the device to TDISP LOCK state:
echo tsm0 > /sys/bus/pci/devices/${DEVICE}/tsm/lock

To transition the device to TDISP RUN state:
echo 1 > /sys/bus/pci/devices/${DEVICE}/tsm/accept

echo ${DEVICE} > /sys/bus/pci/drivers_probe

Changes from v3:
https://lore.kernel.org/all/[email-masked]
* updated the patches to follow the RMM 2.0bet1 specification
* updated the guest-side DA code to use the renamed identity/protocol digest
  fields and id_index

Changes from v2:
rfc-v2: https://lore.kernel.org/all/[email-masked]
* rebase to latest kernel and core TSM changes
* Address review feedback.
* Interface report is now collected using core TSM framework
* swiotlb is now considered shared-memory pool and is not allowed to be used by accepted devices.

v1:
rfc-v1: https://lore.kernel.org/all/[email-masked]

[1] https://developer.arm.com/documentation/den0137/2-0bet1/
[2] https://lore.kernel.org/all/[email-masked]
[3] https://gitlab.arm.com/linux-arm/linux-cca.git cca/topics/cca-tdisp-upstream-rfc-v4

Cc: Alexey Kardashevskiy <[email-masked]>
Cc: Catalin Marinas <[email-masked]>
Cc: Dan Williams <[email-masked]>
Cc: Jason Gunthorpe <[email-masked]>
Cc: Jonathan Cameron <[email-masked]>
Cc: Marc Zyngier <[email-masked]>
Cc: Samuel Ortiz <[email-masked]>
Cc: Steven Price <[email-masked]>
Cc: Suzuki K Poulose <[email-masked]>
Cc: Will Deacon <[email-masked]>
Cc: Xu Yilun <[email-masked]>

Aneesh Kumar K.V (Arm) (11):
  coco: guest: arm64: Guest TSM callback and realm device lock support
  coco: guest: arm64: Fix a typo in the ARM_CCA_GUEST Kconfig help
    string ("and" -> "an").
  coco: guest: arm64: Add Realm Host Interface and guest DA helper
  coco: guest: arm64: Support guest-initiated TDI lock/unlock
    transitions
  coco: guest: arm64: Refresh interface-report cache during device lock
  coco: guest: arm64: Add measurement refresh via
    RHI_DA_VDEV_GET_MEASUREMENTS
  coco: guest: arm64: Add guest APIs to read host-cached DA objects
  coco: guest: arm64: Verify DA evidence with RSI_VDEV_GET_INFO digests
  coco: guest: arm64: Hook TSM accept to Realm TDISP RUN transition
  coco: arm64: dma: Update force_dma_unencrypted for accepted devices
  coco: guest: arm64: Enable vdev DMA after attestation

 arch/arm64/include/asm/mem_encrypt.h      |   6 +-
 arch/arm64/include/asm/rhi.h              |  59 ++++
 arch/arm64/include/asm/rsi.h              |   1 +
 arch/arm64/include/asm/rsi_cmds.h         |  73 +++++
 arch/arm64/include/asm/rsi_smc.h          |  63 ++++
 arch/arm64/kernel/rsi.c                   |  10 +
 arch/arm64/mm/mem_encrypt.c               |  10 +
 drivers/virt/coco/Makefile                |   2 +-
 drivers/virt/coco/arm-cca-guest/Kconfig   |   9 +-
 drivers/virt/coco/arm-cca-guest/Makefile  |   1 +
 drivers/virt/coco/arm-cca-guest/arm-cca.c | 358 +++++++++++++++++++++-
 drivers/virt/coco/arm-cca-guest/rhi-da.c  | 356 +++++++++++++++++++++
 drivers/virt/coco/arm-cca-guest/rhi-da.h  |  17 +
 drivers/virt/coco/arm-cca-guest/rsi-da.c  | 289 +++++++++++++++++
 drivers/virt/coco/arm-cca-guest/rsi-da.h  |  66 ++++
 include/linux/swiotlb.h                   |   3 +
 kernel/dma/direct.c                       |   8 +
 kernel/dma/swiotlb.c                      |   3 +
 18 files changed, 1326 insertions(+), 8 deletions(-)
 create mode 100644 drivers/virt/coco/arm-cca-guest/rhi-da.c
 create mode 100644 drivers/virt/coco/arm-cca-guest/rhi-da.h
 create mode 100644 drivers/virt/coco/arm-cca-guest/rsi-da.c
 create mode 100644 drivers/virt/coco/arm-cca-guest/rsi-da.h

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2.43.0