[Qemu-devel] [PATCH v1 0/3] intel_iommu: support scalable mode

[Yi Sun]

Intel vt-d rev3.0 [1] introduces a new translation mode called
'scalable mode', which enables PASID-granular translations for
first level, second level, nested and pass-through modes. The
vt-d scalable mode is the key ingredient to enable Scalable I/O
Virtualization (Scalable IOV) [2] [3], which allows sharing a
device in minimal possible granularity (ADI - Assignable Device
Interface). As a result, previous Extended Context (ECS) mode
is deprecated (no production ever implements ECS).

This patch set emulates a minimal capability set of VT-d scalable
mode, equivalent to what is available in VT-d legacy mode today:
    1. Scalable mode root entry, context entry and PASID table
    2. Seconds level translation under scalable mode
    3. Queued invalidation (with 256 bits descriptor)
    4. Pass-through mode

Corresponding intel-iommu driver support will be included in
kernel 5.0:
    https://www.spinics.net/lists/kernel/msg2985279.html

We will add emulation of full scalable mode capability along with
guest iommu driver progress later, e.g.:
    1. First level translation
    2. Nested translation
    3. Per-PASID invalidation descriptors
    4. Page request services for handling recoverable faults

To verify the patches, below cases were tested according to Peter Xu's
suggestions.
    
+---------+----------------------------------------------------------------+----------------------------------------------------------------+
    |         |                      w/ Device Passthr                         
|                     w/o Device Passthr                         |
    |         
+-------------------------------+--------------------------------+-------------------------------+--------------------------------+
    |         | virtio-net-pci, vhost=on      | virtio-net-pci, vhost=off      
| virtio-net-pci, vhost=on      | virtio-net-pci, vhost=off      |
    |         
+-------------------------------+--------------------------------+-------------------------------+--------------------------------+
    |         | netperf | kernel bld | data cp| netperf | kernel bld | data cp 
| netperf | kernel bld | data cp| netperf | kernel bld | data cp |
    
+---------+-------------------------------+--------------------------------+-------------------------------+--------------------------------+
    | Legacy  | Pass    | Pass       | Pass   | Pass    | Pass       | Pass    
| Pass    | Pass       | Pass   | Pass    | Pass       | Pass    |
    
+---------+-------------------------------+--------------------------------+-------------------------------+--------------------------------+
    | Scalable| Pass    | Pass       | Pass   | Pass    | Pass       | Pass    
| Pass    | Pass       | Pass   | Pass    | Pass       | Pass    |
    
+---------+-------------------------------+--------------------------------+-------------------------------+--------------------------------+

References:
[1] 
https://software.intel.com/en-us/download/intel-virtualization-technology-for-directed-io-architecture-specification
[2] 
https://software.intel.com/en-us/download/intel-scalable-io-virtualization-technical-specification
[3] https://schd.ws/hosted_files/lc32018/00/LC3-SIOV-final.pdf

---
RFC v2->v1

Patch 1:
    - revert unnecessary rename in 'vtd_ce_present".
    - use 'ce_size' to judge if it is scalable mode in
      'vtd_get_context_entry_from_root'.
    - remove some 'inline' declarations.
    - remove unnecessary scalable mode check in 'vtd_ce_type_check' and
      make corresponding changes in 'vtd_dev_to_context_entry'.
    - add 'VTD_FR_PASID_TABLE_INV' case in 'vtd_qualified_faults[]'.
    - create a macro function to handle a repeated pattern about 'is_fpd_set'.
    - explicitly print 'legacy mode' when calling 'trace_vtd_replay_ce_valid'.
Patch 2:
    - do "(val & VTD_IQT_QT_256_RSV_BIT)" to be clear.
Patch 3:
    - move 's->dma_drain' check from 'vtd_init' to 'vtd_decide_config'.
---

Liu, Yi L (2):
  intel_iommu: scalable mode emulation
  intel_iommu: add 256 bits qi_desc support

Yi Sun (1):
  intel_iommu: add scalable-mode option to make scalable mode work

 hw/i386/intel_iommu.c          | 559 +++++++++++++++++++++++++++++++++--------
 hw/i386/intel_iommu_internal.h |  54 +++-
 hw/i386/trace-events           |   2 +-
 include/hw/i386/intel_iommu.h  |  28 ++-
 4 files changed, 533 insertions(+), 110 deletions(-)

-- 
1.9.1