This series forms the second half of the subsystem-wide ATS robustness
updates. The first part (focusing on the core subsystem, Intel, and ARM
SMMUv3) has already been merged upstream [1]. This half addresses the
AMD IOMMU driver and standardizes the PCI ATS API.
In v2, the series has been significantly restructured based on feedback
on v1.
[v4]
- https://lore.kernel.org/all/20260824122347.1588592-1-praan@google.com/
- Dropped iommu_ignore_device() and dropped patch 3 per discussion with
Jason and Vasant.
- Renamed iommu_lookup_device() to lookup_device().
- Cleaned up amd_iommu_probe_device() to return error pointers directly.
- Collected Reviewed-by tags from Jason, Vasant and Sami.
[v3]
- Collected Reviewed-by tags from Vasant.
- Added a comment explaining why devices without DMA translation support
are not ignored (to preserve interrupt remapping) per Vasant's feedback.
- Renamed iommu_disable_device_dma() to iommu_disable_device() to
accurately reflect that it disables both DMA and interrupt remapping.
[v2]
- https://lore.kernel.org/all/20260814015647.3370124-1-praan@google.com/
- Patch 1 Refctors the probe path, isolating capabilities into
iommu_init_device_caps().
- Patch 2 renames iommu_ignore_device() to iommu_disable_device_dma().
Following Jason's suggestion, it invalidates the hardware DTE by
clearing the Valid bit (lower 128 bits) followed by the upper
128 bits.
- Patch 3 splits the probe error paths to ensure that devices with
config failures (like PD_MODE_NONE or ATS mismatches) can preserve
their rlookup_table entries, successfully keeping IRQ remapping
functional for bypassed devices.
- Patch 4 implements the "Fail Hard" pattern for ATS in the AMD driver,
failing the probe and throwing a WARN_ON() upon ATS configuration or
enablement failures.
- Patch 5 enforces the checking of pci_ats_supported() prior to calling
pci_prepare_ats() across the entire kernel PCI subsystem.
[v1]
- https://lore.kernel.org/all/20260601134204.2150602-1-praan@google.com/
Thanks,
Praan
[1] https://lore.kernel.org/all/20260615235037.259909-1-praan@google.com/
Pranjal Shrivastava (4):
iommu/amd: Refactor device probe and capability initialization
iommu/amd: Remove iommu_ignore_device()
iommu/amd: Fail probe on ATS configuration failure
PCI/ATS: Mandate checking pci_ats_supported() before pci_prepare_ats()
drivers/iommu/amd/iommu.c | 164 +++++++++++++++++++-------------------
drivers/pci/ats.c | 6 +-
2 files changed, 86 insertions(+), 84 deletions(-)
--
2.55.0.1003.g10538fe699-goog