[PATCH v3 vfio 0/7] pds vfio driver

[Brett Creeley <brett.creeley@amd.com>]

This is a draft patchset for a new vendor specific VFIO driver
(pds_vfio) for use with the AMD/Pensando Distributed Services Card
(DSC). This driver is device type agnostic and live migration is
supported as long as the underlying SR-IOV VF supports live migration
on the DSC. This driver is a client of the newly introduced pds_core
driver, which the latest version can be referenced at:

https://lore.kernel.org/netdev/20230217225558.19837-1-shannon.nelson@amd.com/

This driver will use the pds_core device and auxiliary_bus as the VFIO
control path to the DSC. The pds_core device creates auxiliary_bus
devices for each live migratable VF. The devices are named by their
feature plus the VF PCI BDF so the auxiliary_bus driver implemented by
pds_vfio can find its related VF PCI driver instance. Once this
auxiliary bus connection is configured, the pds_vfio driver can send
admin queue commands to the device and receive events from pds_core.

An ASCII diagram of a VFIO instance looks something like this and can
be used with the VFIO subsystem to provide devices VFIO and live
migration support.

                               .------.  .--------------------------.
                               | QEMU |--|  VM     .-------------.  |
                               '......'  |         | PCI driver  |  |
                                  |      |         .-------------.  |
                                  |      |         |  SR-IOV VF  |  |
                                  |      |         '-------------'  |
                                  |      '---------------||---------'
                               .--------------.          ||
                               |/dev/<vfio_fd>|          ||
                               '--------------'          ||
Host Userspace                         |                 ||
===================================================      ||
Host Kernel                            |                 ||
                                       |                 ||
           pds_core.LM.2305 <--+   .--------.            ||
                   |           |   |vfio-pci|            ||
                   |           |   '--------'            ||
                   |           |       |                 ||
         .------------.       .-------------.            ||
         |  pds_core  |       |   pds_vfio  |            ||
         '------------'       '-------------'            ||
               ||                   ||                   ||
             09:00.0              09:00.1                ||
== PCI ==================================================||=====
               ||                   ||                   ||
          .----------.         .----------.              ||
    ,-----|    PF    |---------|    VF    |-------------------,
    |     '----------'         '----------'  |       VF       |
    |                     DSC                |  data/control  |
    |                                        |      path      |
    -----------------------------------------------------------


The pds_vfio driver is targeted to reside in drivers/vfio/pci/pds.
It makes use of and introduces new files in the common include/linux/pds
include directory.

Changes:

v3:
- Update copyright year to 2023 and use "Advanced Micro Devices, Inc."
  for the company name
- Clarify the fact that AMD/Pensando's VFIO solution is device type
  agnostic, which aligns with other current VFIO solutions
- Add line in drivers/vfio/pci/Makefile to build pds_vfio
- Move documentation to amd sub-directory
- Remove some dead code due to the pds_core implementation of
  listening to BIND/UNBIND events
- Move a dev_dbg() to a previous patch in the series
- Add implementation for vfio_migration_ops.migration_get_data_size to
  return the maximum possible device state size

RFC to v2:
https://lore.kernel.org/all/20221214232136.64220-1-brett.creeley@amd.com/
- Implement state transitions for VFIO_MIGRATION_P2P flag
- Improve auxiliary driver probe by returning EPROBE_DEFER
  when the PCI driver is not set up correctly
- Add pointer to docs in
  Documentation/networking/device_drivers/ethernet/index.rst

RFC:
https://lore.kernel.org/all/20221207010705.35128-1-brett.creeley@amd.com/

Brett Creeley (7):
  vfio/pds: Initial support for pds_vfio VFIO driver
  vfio/pds: Add support to register as PDS client
  vfio/pds: Add VFIO live migration support
  vfio: Commonize combine_ranges for use in other VFIO drivers
  vfio/pds: Add support for dirty page tracking
  vfio/pds: Add support for firmware recovery
  vfio/pds: Add Kconfig and documentation

 .../device_drivers/ethernet/amd/pds_vfio.rst  |  88 +++
 .../device_drivers/ethernet/index.rst         |   1 +
 MAINTAINERS                                   |   7 +
 drivers/vfio/pci/Kconfig                      |   2 +
 drivers/vfio/pci/Makefile                     |   2 +
 drivers/vfio/pci/mlx5/cmd.c                   |  48 +-
 drivers/vfio/pci/pds/Kconfig                  |  19 +
 drivers/vfio/pci/pds/Makefile                 |  12 +
 drivers/vfio/pci/pds/aux_drv.c                | 210 +++++++
 drivers/vfio/pci/pds/aux_drv.h                |  28 +
 drivers/vfio/pci/pds/cmds.c                   | 485 ++++++++++++++++
 drivers/vfio/pci/pds/cmds.h                   |  44 ++
 drivers/vfio/pci/pds/dirty.c                  | 541 ++++++++++++++++++
 drivers/vfio/pci/pds/dirty.h                  |  48 ++
 drivers/vfio/pci/pds/lm.c                     | 491 ++++++++++++++++
 drivers/vfio/pci/pds/lm.h                     |  53 ++
 drivers/vfio/pci/pds/pci_drv.c                | 126 ++++
 drivers/vfio/pci/pds/pci_drv.h                |  14 +
 drivers/vfio/pci/pds/vfio_dev.c               | 239 ++++++++
 drivers/vfio/pci/pds/vfio_dev.h               |  42 ++
 drivers/vfio/vfio_main.c                      |  48 ++
 include/linux/pds/pds_lm.h                    | 391 +++++++++++++
 include/linux/vfio.h                          |   3 +
 23 files changed, 2895 insertions(+), 47 deletions(-)
 create mode 100644 Documentation/networking/device_drivers/ethernet/amd/pds_vfio.rst
 create mode 100644 drivers/vfio/pci/pds/Kconfig
 create mode 100644 drivers/vfio/pci/pds/Makefile
 create mode 100644 drivers/vfio/pci/pds/aux_drv.c
 create mode 100644 drivers/vfio/pci/pds/aux_drv.h
 create mode 100644 drivers/vfio/pci/pds/cmds.c
 create mode 100644 drivers/vfio/pci/pds/cmds.h
 create mode 100644 drivers/vfio/pci/pds/dirty.c
 create mode 100644 drivers/vfio/pci/pds/dirty.h
 create mode 100644 drivers/vfio/pci/pds/lm.c
 create mode 100644 drivers/vfio/pci/pds/lm.h
 create mode 100644 drivers/vfio/pci/pds/pci_drv.c
 create mode 100644 drivers/vfio/pci/pds/pci_drv.h
 create mode 100644 drivers/vfio/pci/pds/vfio_dev.c
 create mode 100644 drivers/vfio/pci/pds/vfio_dev.h
 create mode 100644 include/linux/pds/pds_lm.h

-- 
2.17.1