This is the device driver API for SVA (Shared Virtual Addressing).
Changes since v1 [1]:
* Following comments, return a handle rather than a PASID. I agree that
it makes things easier for device drivers as well, because they don't
need to worry about the unbind()/mm_exit() race as much. Previously
they couldn't issue an unbind() if the mm exited since the PASID could
have been reallocated.
* If a handle already exists, reuse it and take a reference instead of
returning EEXIST. As noted by Zhangfei and myself during development,
it can make things a bit easier for device drivers that need to handle
multiple threads in a process issuing bind() for the same dev and mm.
The four dev_feature functions are implemented by Lu Baolu's IOMMU-aware
mdev series [2].
iommu_dev_has_feature(dev, IOMMU_DEV_FEAT_SVA) -> true/false
iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) -> 0/err
iommu_dev_disable_feature(dev, IOMMU_DEV_FEAT_SVA) -> 0/err
iommu_dev_feature_enabled(dev, IOMMU_DEV_FEAT_SVA) -> true/false
Patch 1/1 adds the next four functions, once the SVA feature is enabled:
iommu_sva_bind(dev, mm, drvdata) -> handle
/*
* Only exit_mm() for now, but later callbacks to deal with
* unhandled PRI faults and possible others:
*/
iommu_sva_set_ops(handle, iommu_sva_ops) -> 0/err
iommu_sva_get_pasid(handle) -> pasid/invalid
iommu_sva_unbind(handle)
Full support for the SMMUv3 can be found at [3]
[1]
https://lore.kernel.org/lkml/20190220142759.33308-1-jean-philippe.bruc...@arm.com/
[2]
https://lore.kernel.org/lkml/20190213040301.23021-10-baolu...@linux.intel.com/T/
[3] git://linux-arm.org/linux-jpb.git sva/current
http://www.linux-arm.org/git?p=linux-jpb.git;a=shortlog;h=refs/heads/sva/current
Jean-Philippe Brucker (1):
iommu: Bind process address spaces to devices
drivers/iommu/iommu.c | 105 ++++++++++++++++++++++++++++++++++++++++++
include/linux/iommu.h | 71 ++++++++++++++++++++++++++++
2 files changed, 176 insertions(+)
--
2.21.0
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