Re: [PATCH v5 00/23] IOMMU and VT-d driver support for Shared Virtual Address (SVA)

[Jacob Pan <jacob.jun.pan@linux.intel.com>]

Hi Joerg,

Just wondering if you had a chance to review this version before I
spin another one mostly based on Baolu's comments. I have incorporated
feedbacks from your review on the previous version, but it was a while
ago.

Thanks,

Jacob

On Fri, 11 May 2018 13:53:52 -0700
Jacob Pan <jacob.jun.pan@linux.intel.com> wrote:

> Shared virtual address (SVA), a.k.a, Shared virtual memory (SVM) on
> Intel platforms allow address space sharing between device DMA and
> applications. SVA can reduce programming complexity and enhance
> security. To enable SVA in the guest, i.e. shared guest application
> address space and physical device DMA address, IOMMU driver must
> provide some new functionalities.
> 
> This patchset is a follow-up on the discussions held at LPC 2017
> VFIO/IOMMU/PCI track. Slides and notes can be found here:
> https://linuxplumbersconf.org/2017/ocw/events/LPC2017/tracks/636
> 
> The complete guest SVA support also involves changes in QEMU and VFIO,
> which has been posted earlier.
> https://www.spinics.net/lists/kvm/msg148798.html
> 
> This is the IOMMU portion follow up of the more complete series of the
> kernel changes to support vSVA. Please refer to the link below for
> more details. https://www.spinics.net/lists/kvm/msg148819.html
> 
> Generic APIs are introduced in addition to Intel VT-d specific
> changes, the goal is to have common interfaces across IOMMU and
> device types for both VFIO and other in-kernel users.
> 
> At the top level, new IOMMU interfaces are introduced as follows:
>  - bind guest PASID table
>  - passdown invalidations of translation caches
>  - IOMMU device fault reporting including page request/response and
>    non-recoverable faults.
> 
> For IOMMU detected device fault reporting, struct device is extended
> to provide callback and tracking at device level. The original
> proposal was discussed here "Error handling for I/O memory management
> units" (https://lwn.net/Articles/608914/). I have experimented two
> alternative solutions:
> 1. use a shared group notifier, this does not scale well also causes
> unwanted notification traffic when group sibling device is reported
> with faults. 2. place fault callback at device IOMMU arch data, e.g.
> device_domain_info in Intel/FSL IOMMU driver. This will cause code
> duplication, since per device fault reporting is generic.
> 
> The additional patches are Intel VT-d specific, which either
> implements or replaces existing private interfaces with the generic
> ones.
> 
> This patchset is based on the work and ideas from many people,
> especially: Ashok Raj <ashok.raj@intel.com>
> Liu, Yi L <yi.l.liu@linux.intel.com>
> Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> 
> Thanks,
> 
> Jacob
> 
> V5
> 	- Removed device context cache and non-pasid TLB invalidation
> type
> 	- Simplified and sorted granularities for the remaining TLB
> 	invalidation types, per discussion and review by
> Jean-Philippe Brucker.
> 	- Added a setup parameter for page response timeout
> 	- Added version and size checking in bind PASID and
> invalidation APIs
> 	- Fixed locking and error handling in device fault reporting
> API based on Jean's review
> 
> V4
> 	- Futher integrate feedback for iommu_param and
> iommu_fault_param from Jean and others.
> 	- Handle fault reporting error and race conditions. Keep
> tracking per device pending page requests such that page group
> response can be sanitized.
> 	- Added a timer to handle irresponsive guest who does not
> send page response on time.
> 	- Use a workqueue for VT-d non-recorverable IRQ fault
> handling.
> 	- Added trace events for invalidation and fault reporting.
> V3
> 	- Consolidated fault reporting data format based on
> discussions on v2, including input from ARM and AMD.
> 	- Renamed invalidation APIs from svm to sva based on
> discussions on v2
> 	- Use a parent pointer under struct device for all iommu per
> device data
> 	- Simplified device fault callback, allow driver private data
> to be registered. This might make it easy to replace domain fault
> handler. V2
> 	- Replaced hybrid interface data model (generic data + vendor
> specific data) with all generic data. This will have the security
> benefit where data passed from user space can be sanitized by all
> software layers if needed.
> 	- Addressed review comments from V1
> 	- Use per device fault report data
> 	- Support page request/response communications between host
> IOMMU and guest or other in-kernel users.
> 	- Added unrecoverable fault reporting to DMAR
> 	- Use threaded IRQ function for DMAR fault interrupt and fault
> 	  reporting
> 
> Jacob Pan (22):
>   iommu: introduce bind_pasid_table API function
>   iommu/vt-d: move device_domain_info to header
>   iommu/vt-d: add a flag for pasid table bound status
>   iommu/vt-d: add bind_pasid_table function
>   iommu/vt-d: add definitions for PFSID
>   iommu/vt-d: fix dev iotlb pfsid use
>   iommu/vt-d: support flushing more translation cache types
>   iommu/vt-d: add svm/sva invalidate function
>   iommu: introduce device fault data
>   driver core: add per device iommu param
>   iommu: add a timeout parameter for prq response
>   iommu: introduce device fault report API
>   iommu: introduce page response function
>   iommu: handle page response timeout
>   iommu/config: add build dependency for dmar
>   iommu/vt-d: report non-recoverable faults to device
>   iommu/intel-svm: report device page request
>   iommu/intel-svm: replace dev ops with fault report API
>   iommu/intel-svm: do not flush iotlb for viommu
>   iommu/vt-d: add intel iommu page response function
>   trace/iommu: add sva trace events
>   iommu: use sva invalidate and device fault trace event
> 
> Liu, Yi L (1):
>   iommu: introduce iommu invalidate API function
> 
>  Documentation/admin-guide/kernel-parameters.txt |   8 +
>  drivers/iommu/Kconfig                           |   1 +
>  drivers/iommu/dmar.c                            | 209 ++++++++++++++-
>  drivers/iommu/intel-iommu.c                     | 338
> ++++++++++++++++++++++--
> drivers/iommu/intel-svm.c                       |  84 ++++--
> drivers/iommu/iommu.c                           | 311
> +++++++++++++++++++++-
> include/linux/device.h                          |   3 +
> include/linux/dma_remapping.h                   |   1 +
> include/linux/dmar.h                            |   2 +-
> include/linux/intel-iommu.h                     |  52 +++-
> include/linux/intel-svm.h                       |  20 +-
> include/linux/iommu.h                           | 216 ++++++++++++++-
> include/trace/events/iommu.h                    | 112 ++++++++
> include/uapi/linux/iommu.h                      | 124 +++++++++ 14
> files changed, 1409 insertions(+), 72 deletions(-) create mode 100644
> include/uapi/linux/iommu.h
> 

[Jacob Pan]