mbox series

[v11,00/10] iommu: I/O page faults for SMMUv3

Message ID 20210125110650.3232195-1-jean-philippe@linaro.org
Headers show
Series iommu: I/O page faults for SMMUv3 | expand

Message

Jean-Philippe Brucker Jan. 25, 2021, 11:06 a.m. UTC 
Add stall support to the SMMUv3, along with a common I/O Page Fault
handler.

This version fixes a typo introduced in v10 [1] and adds review tags
(thanks!) You can find the range diff for v10->v11 below.

[1] https://lore.kernel.org/linux-iommu/20210121123623.2060416-1-jean-philippe@linaro.org/

Jean-Philippe Brucker (10):
  iommu: Fix comment for struct iommu_fwspec
  iommu/arm-smmu-v3: Use device properties for pasid-num-bits
  iommu: Separate IOMMU_DEV_FEAT_IOPF from IOMMU_DEV_FEAT_SVA
  iommu/vt-d: Support IOMMU_DEV_FEAT_IOPF
  uacce: Enable IOMMU_DEV_FEAT_IOPF
  iommu: Add a page fault handler
  iommu/arm-smmu-v3: Maintain a SID->device structure
  dt-bindings: document stall property for IOMMU masters
  ACPI/IORT: Enable stall support for platform devices
  iommu/arm-smmu-v3: Add stall support for platform devices

 drivers/iommu/Makefile                        |   1 +
 .../devicetree/bindings/iommu/iommu.txt       |  18 +
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  56 ++-
 drivers/iommu/iommu-sva-lib.h                 |  53 ++
 include/linux/iommu.h                         |  26 +-
 drivers/acpi/arm64/iort.c                     |  15 +-
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   |  59 ++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 349 +++++++++++--
 drivers/iommu/intel/iommu.c                   |  11 +-
 drivers/iommu/io-pgfault.c                    | 461 ++++++++++++++++++
 drivers/iommu/of_iommu.c                      |   5 -
 drivers/misc/uacce/uacce.c                    |  39 +-
 12 files changed, 1019 insertions(+), 74 deletions(-)
 create mode 100644 drivers/iommu/io-pgfault.c

Comments

Jean-Philippe Brucker Jan. 25, 2021, 3:46 p.m. UTC | #1 
On Mon, Jan 25, 2021 at 01:50:09PM +0000, Jonathan Cameron wrote:
> > +static int arm_smmu_master_sva_enable_iopf(struct arm_smmu_master *master)
> > +{
> > +	int ret;
> > +	struct device *dev = master->dev;
> > +
> > +	/*
> > +	 * Drivers for devices supporting PRI or stall should enable IOPF first.
> > +	 * Others have device-specific fault handlers and don't need IOPF.
> > +	 */
> > +	if (!arm_smmu_master_iopf_supported(master))
> 
> So if we have master->iopf_enabled and this happens. Then I'm not totally sure
> what prevents the disable below running its cleanup on stuff that was never
> configured.

Since arm_smmu_dev_enable_feature() checks that the feature is supported,
iopf_enabled can only be true if arm_smmu_master_iopf_supported() is true.

What's missing is checking that drivers don't disable IOPF while SVA is
enabled - or else the disable below can leak. Another thing I broke in v10 :/

Thanks,
Jean

> 
> > +		return 0;
> > +
> > +	if (!master->iopf_enabled)
> > +		return -EINVAL;
> > +
> > +	ret = iopf_queue_add_device(master->smmu->evtq.iopf, dev);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf, dev);
> > +	if (ret) {
> > +		iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
> > +		return ret;
> > +	}
> > +	return 0;
> > +}
> > +
> > +static void arm_smmu_master_sva_disable_iopf(struct arm_smmu_master *master)
> > +{
> > +	struct device *dev = master->dev;
> > +
> > +	if (!master->iopf_enabled)
> > +		return;
> 
> As above, I think you need a sanity check on
> 
> !arm_smmu_master_iopf_supported(master) before clearing the following.
> 
> I may well be missing something that stops us getting here though.
> 
> Alternative is probably to sanity check iopf_enabled = true is supported
> before letting a driver set it.
> 
> 
> > +
> > +	iommu_unregister_device_fault_handler(dev);
> > +	iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
> > +}