[PATCH v6 00/25] iommu: Shared Virtual Addressing for SMMUv3

Jean-Philippe Brucker
2020-04-30T14:40:57Z

Shared Virtual Addressing (SVA) allows to share process page tables with
devices using the IOMMU, PASIDs and I/O page faults. Add SVA support to
the Arm SMMUv3 driver.

Since v5 [1]:

* Added patches 1-3. Patch 1 adds a PASID field to mm_struct as
discussed in [1] and [2]. This is also needed for Intel ENQCMD. Patch
2 adds refcounts to IOASID and patch 3 adds a couple of helpers to
allocate the PASID.

* Dropped most of iommu-sva.c. After getting rid of io_mm following
review of v5, there wasn't enough generic code left to justify the
indirect branch overhead of io_mm_ops in the MMU notifiers. I ended up
with more glue than useful code, and couldn't find an easy way to deal
with domains in the SMMU driver (we keep PASID tables per domain,
while x86 keeps them per device). The direct approach in patch 17 is
nicer and a little easier to read. The SMMU driver only gained 160
lines, while iommu-sva lost 470 lines.

As a result I dropped the MMU notifier patch.

Jacob, one upside of this rework is that we now free ioasids in
blocking context, which might help with your addition of notifiers to
ioasid.c

* Simplified io-pgfault a bit, since flush() isn't called from mm exit
path anymore.

* Fixed a bug in patch 17 (don't clear the stall bit when stall is
forced).

You can find the latest version on https://jpbrucker.net/git/linux
branch sva/current, and sva/zip-devel for the Hisilicon zip accelerator.

[1] https://lore.kernel.org/linux-iommu/20200414170252.714402-1-jean-philippe@linaro.org/
[2] https://lore.kernel.org/linux-iommu/1585596788-193989-6-git-send-email-fenghua.yu@intel.com/

Jean-Philippe Brucker (25):
mm: Add a PASID field to mm_struct
iommu/ioasid: Add ioasid references
iommu/sva: Add PASID helpers
iommu: Add a page fault handler
iommu/iopf: Handle mm faults
arm64: mm: Add asid_gen_match() helper
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 SVA device feature
iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind()
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
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 PRI functions
iommu/arm-smmu-v3: Add support for PRI

drivers/iommu/Kconfig | 11 +
drivers/iommu/Makefile | 2 +
.../devicetree/bindings/iommu/iommu.txt | 18 +
arch/arm64/include/asm/mmu.h | 1 +
arch/arm64/include/asm/mmu_context.h | 11 +-
drivers/iommu/io-pgtable-arm.h | 30 +
drivers/iommu/iommu-sva.h | 15 +
include/linux/ioasid.h | 10 +-
include/linux/iommu.h | 53 +
include/linux/mm_types.h | 4 +
include/linux/pci-ats.h | 8 +
arch/arm64/kernel/cpufeature.c | 1 +
arch/arm64/mm/context.c | 103 +-
drivers/iommu/arm-smmu-v3.c | 1554 +++++++++++++++--
drivers/iommu/io-pgfault.c | 458 +++++
drivers/iommu/io-pgtable-arm.c | 27 +-
drivers/iommu/ioasid.c | 30 +-
drivers/iommu/iommu-sva.c | 85 +
drivers/iommu/of_iommu.c | 5 +-
drivers/pci/ats.c | 4 +
MAINTAINERS | 3 +-
21 files changed, 2275 insertions(+), 158 deletions(-)
create mode 100644 drivers/iommu/io-pgtable-arm.h
create mode 100644 drivers/iommu/iommu-sva.h
create mode 100644 drivers/iommu/io-pgfault.c
create mode 100644 drivers/iommu/iommu-sva.c

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2.26.2