Subject: [PATCH v2 00/11] iommu/arm-smmu-v3: Add PRI support

From: Nicolin Chen <[email-masked]>
Date: Thu, 28 May 2026 00:59:28 -0700

The SMMUv3 driver doesn't handle events on the PRI queue or respond to IOPF
faults. This series adds the missing pieces, using the IOPF infrastructure,
to convert PRI page requests into iopf_faults and issue CMDQ_OP_PRI_RESP.

The iopf_queue_flush_dev() contract requires the driver to first drain the
hardware PRI queue and synchronize using a threaded IRQ handler before the
IOPF software flush. This drove the additional commits compared to v1:
 - arm_smmu_drain_queue_for_iopf() drains the hardware queue to the PROD
   snapshot
 - arm_smmu_attach_release() moves the teardown outside the global lock
 - synchronize_irq() closes the gap before the final flush

This is on Github:
https://github.com/nicolinc/iommufd/commits/smmuv3_pri-v2

FWIW, engineers on the NVIDIA side have managed to verify the PRI feature.

Changelog
v2:
 * Allocate evtq.iopf for ARM_SMMU_FEAT_PRI
 * Pick up Jean's PRI stubs and PRI export patches
 * Enable PRI for PCI devices in arm_smmu_probe_device()
 * Add arm_smmu_drain_queue_for_iopf() for EVTQ and PRIQ
 * Add arm_smmu_attach_release() to rework the IOPF drain
 * Add IOMMU_FAULT_PAGE_REQUEST_STALLS_TRANS for STALL mode
 * Gate pci_enable_pri() on FEAT_PRI plus a non-NULL evtq.iopf
 * Deny unrecognised-StreamID PRG_LAST in arm_smmu_handle_ppr()
 * Disable PRI when no IRQ handler is registered (unique or combined IRQ)
v1:
 https://lore.kernel.org/all/[email-masked]/

Jean-Philippe Brucker (2):
  PCI/ATS: Add PRI stubs
  PCI/ATS: Export pci_enable_pri() and pci_reset_pri()

Malak Marrid (1):
  iommu/arm-smmu-v3: Submit CMDQ_OP_PRI_RESP for IOPF event

Nicolin Chen (8):
  iommu/arm-smmu-v3: Add arm_smmu_attach_release()
  iommu/arm-smmu-v3: Factor out __queue_empty() and __queue_consumed()
  iommu/arm-smmu-v3: Add arm_smmu_drain_queue_for_iopf() helper
  iommu/arm-smmu-v3: Drain in-flight fault handlers
  iommu/arm-smmu-v3: Support PRI Page Request in arm_smmu_handle_ppr()
  iommu/arm-smmu-v3: Disable PRI when no IRQ handler is registered
  iommu/arm-smmu-v3: Allocate IOPF queue for ARM_SMMU_FEAT_PRI
  iommu/arm-smmu-v3: Enable PRI for PCI device in
    arm_smmu_probe_device()

 drivers/iommu/arm/Kconfig                     |   1 +
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |   3 +
 include/linux/iommu.h                         |   1 +
 include/linux/pci-ats.h                       |   5 +
 .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c     |   1 +
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 244 +++++++++++++++---
 drivers/pci/ats.c                             |   2 +
 7 files changed, 221 insertions(+), 36 deletions(-)

base-commit: 74fa4c177ad09800b007cba043370c887bb1b4e3
-- 
2.43.0