[RFC PATCH v3 00/11] coco/TSM: Arm CCA guest TDISP lock/accept flow with verification and DMA enable

Aneesh Kumar K.V (Arm)
2026-03-12T08:04:53Z

This patch series implements the TSM ->lock(), ->unlock(), and ->accept()
callbacks required for the TDISP setup with Arm CCA as per the RMM ALP17
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

Previous posting:
rfc-v1: https://lore.kernel.org/all/20250728135216.48084-1-aneesh.kumar@kernel.org
rfc-v2: https://lore.kernel.org/all/20251117140007.122062-1-aneesh.kumar@kernel.org

Changes from v2:
* 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.

[1] https://developer.arm.com/-/cdn-downloads/permalink/Architectures/Armv9/DEN0137_1.1-alp17.zip
[2] https://lore.kernel.org/all/20260303000207.1836586-1-dan.j.williams@intel.com
[3] https://gitlab.arm.com/linux-arm/linux-cca.git cca/topics/cca-tdisp-upstream-rfc-v3

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 | 58 ++++
arch/arm64/include/asm/rsi.h | 1 +
arch/arm64/include/asm/rsi_cmds.h | 73 +++++
arch/arm64/include/asm/rsi_smc.h | 51 +++
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 | 345 +++++++++++++++++++++
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 | 65 ++++
include/linux/swiotlb.h | 3 +
kernel/dma/direct.c | 8 +
kernel/dma/swiotlb.c | 3 +
18 files changed, 1301 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