Re: [PATCH v4 00/26] iommu: Shared Virtual Addressing and SMMUv3 support

Jonathan Cameron
2020-02-27T18:22:13Z

On Mon, 24 Feb 2020 19:23:35 +0100
Jean-Philippe Brucker <jean-philippe@linaro.org> wrote:

> Shared Virtual Addressing (SVA) allows to share process page tables with
> devices using the IOMMU. Add a generic implementation of the IOMMU SVA
> API, and add support in the Arm SMMUv3 driver.
>
> Previous versions of this patchset were sent over a year ago [1][2] but
> we've made a lot of progress since then:
>
> * ATS support for SMMUv3 was merged in v5.2.
> * The bind() and fault reporting APIs have been merged in v5.3.
> * IOASID were added in v5.5.
> * SMMUv3 PASID was added in v5.6, with some pending for v5.7.
>
> * The first user of the bind() API will be merged in v5.7 [3]. The zip
> accelerator is also the first piece of hardware that I've been able to
> use for testing (previous versions were developed with software models)
> and I now have tools for evaluating SVA performance. Unfortunately I
> still don't have hardware that supports ATS and PRI; the zip accelerator
> uses stall.
>
> These are the remaining changes for SVA support in SMMUv3. Since v3 [1]
> I fixed countless bugs and - I think - addressed everyone's comments.
> Thanks to recent MMU notifier rework, iommu-sva.c is a lot more
> straightforward. I'm still unhappy with the complicated locking in the
> SMMUv3 driver resulting from patch 12 (Seize private ASID), but I
> haven't found anything better.
>
> Please find all SVA patches on branches sva/current and sva/zip-devel at
> https://jpbrucker.net/git/linux
>
> [1] https://lore.kernel.org/linux-iommu/20180920170046.20154-1-jean-philippe.brucker@arm.com/
> [2] https://lore.kernel.org/linux-iommu/20180511190641.23008-1-jean-philippe.brucker@arm.com/
> [3] https://lore.kernel.org/linux-iommu/1581407665-13504-1-git-send-email-zhangfei.gao@linaro.org/

Hi Jean-Phillippe.

Great to see this progressing. Other than the few places I've commented
it all looks good to me.

Thanks,

Jonathan

>
> Jean-Philippe Brucker (26):
> mm/mmu_notifiers: pass private data down to alloc_notifier()
> iommu/sva: Manage process address spaces
> iommu: Add a page fault handler
> iommu/sva: Search mm by PASID
> iommu/iopf: Handle mm faults
> iommu/sva: Register page fault handler
> arm64: mm: Pin down ASIDs for sharing mm with devices
> iommu/io-pgtable-arm: Move some definitions to a header
> iommu/arm-smmu-v3: Manage ASIDs with xarray
> arm64: cpufeature: Export symbol read_sanitised_ftr_reg()
> iommu/arm-smmu-v3: Share process page tables
> iommu/arm-smmu-v3: Seize private ASID
> iommu/arm-smmu-v3: Add support for VHE
> iommu/arm-smmu-v3: Enable broadcast TLB maintenance
> iommu/arm-smmu-v3: Add SVA feature checking
> iommu/arm-smmu-v3: Add dev_to_master() helper
> iommu/arm-smmu-v3: Implement mm operations
> iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops
> iommu/arm-smmu-v3: Add support for Hardware Translation Table Update
> iommu/arm-smmu-v3: Maintain a SID->device structure
> iommu/arm-smmu-v3: Ratelimit event dump
> dt-bindings: document stall property for IOMMU masters
> iommu/arm-smmu-v3: Add stall support for platform devices
> PCI/ATS: Add PRI stubs
> PCI/ATS: Export symbols of PRI functions
> iommu/arm-smmu-v3: Add support for PRI
>
> .../devicetree/bindings/iommu/iommu.txt | 18 +
> arch/arm64/include/asm/mmu.h | 1 +
> arch/arm64/include/asm/mmu_context.h | 11 +-
> arch/arm64/kernel/cpufeature.c | 1 +
> arch/arm64/mm/context.c | 103 +-
> drivers/iommu/Kconfig | 13 +
> drivers/iommu/Makefile | 2 +
> drivers/iommu/arm-smmu-v3.c | 1354 +++++++++++++++--
> drivers/iommu/io-pgfault.c | 533 +++++++
> drivers/iommu/io-pgtable-arm.c | 27 +-
> drivers/iommu/io-pgtable-arm.h | 30 +
> drivers/iommu/iommu-sva.c | 596 ++++++++
> drivers/iommu/iommu-sva.h | 64 +
> drivers/iommu/iommu.c | 1 +
> drivers/iommu/of_iommu.c | 5 +-
> drivers/misc/sgi-gru/grutlbpurge.c | 4 +-
> drivers/pci/ats.c | 4 +
> include/linux/iommu.h | 73 +
> include/linux/mmu_notifier.h | 10 +-
> include/linux/pci-ats.h | 8 +
> mm/mmu_notifier.c | 6 +-
> 21 files changed, 2699 insertions(+), 165 deletions(-)
> create mode 100644 drivers/iommu/io-pgfault.c
> create mode 100644 drivers/iommu/io-pgtable-arm.h
> create mode 100644 drivers/iommu/iommu-sva.c
> create mode 100644 drivers/iommu/iommu-sva.h
>