[PATCH V6 mlx5-next 00/15] Add mlx5 live migration driver and v2 migration protocol

[Yishai Hadas <yishaih@nvidia.com>]

This series adds mlx5 live migration driver for VFs that are migration
capable and includes the v2 migration protocol definition and mlx5
implementation.

The mlx5 driver uses the vfio_pci_core split to create a specific VFIO
PCI driver that matches the mlx5 virtual functions. The driver provides
the same experience as normal vfio-pci with the addition of migration
support.

In HW the migration is controlled by the PF function, using its
mlx5_core driver, and the VFIO PCI VF driver co-ordinates with the PF to
execute the migration actions.

The bulk of the v2 migration protocol is semantically the same v1,
however it has been recast into a FSM for the device_state and the
actual syscall interface uses normal ioctl(), read() and write() instead
of building a syscall interface using the region.

Several bits of infrastructure work are included here:
 - pci_iov_vf_id() to help drivers like mlx5 figure out the VF index from
   a BDF
 - pci_iov_get_pf_drvdata() to clarify the tricky locking protocol when a
   VF reaches into its PF's driver
 - mlx5_core uses the normal SRIOV lifecycle and disables SRIOV before
   driver remove, to be compatible with pci_iov_get_pf_drvdata()
 - Lifting VFIO_DEVICE_FEATURE into core VFIO code

This series comes after alot of discussion. Some major points:
- v1 ABI compatible migration defined using the same FSM approach:
   https://lore.kernel.org/all/0-v1-a4f7cab64938+3f-vfio_mig_states_jgg@nvidia.com/
- Attempts to clarify how the v1 API works:
   Alex's:
     https://lore.kernel.org/kvm/163909282574.728533.7460416142511440919.stgit@omen/
   Jason's:
     https://lore.kernel.org/all/0-v3-184b374ad0a8+24c-vfio_mig_doc_jgg@nvidia.com/
- Etherpad exploring the scope and questions of general VFIO migration:
     https://lore.kernel.org/kvm/87mtm2loml.fsf@redhat.com/

NOTE: As this series touched mlx5_core parts we need to send this in a
pull request format to VFIO to avoid conflicts.

Matching qemu changes can be previewed here:
 https://github.com/jgunthorpe/qemu/commits/vfio_migration_v2

Changes from V5: https://lore.kernel.org/kvm/20211027095658.144468-1-yishaih@nvidia.com/
vfio:
- Migration protocol v2:
  + enum for device state, not bitmap
  + ioctl to manipulate device_state, not a region
  + Only STOP_COPY is mandatory, P2P and PRE_COPY are optional, discovered
    via VFIO_DEVICE_FEATURE
  + Migration data transfer is done via dedicated FD
- VFIO core code to implement the migration related ioctls and help
  drivers implement it correctly
- VFIO_DEVICE_FEATURE refactor
- Delete migration protocol, drop patches fixing it
- Drop "vfio/pci_core: Make the region->release() function optional"
vfio/mlx5:
- Switch to use migration v2 protocol, with core helpers
- Eliminate the region implementation

Changes from V4: https://lore.kernel.org/kvm/20211026090605.91646-1-yishaih@nvidia.com/
vfio:
- Add some Reviewed-by.
- Rename to vfio_pci_core_aer_err_detected() as Alex asked.
vfio/mlx5:
- Improve to enter the error state only if unquiesce also fails.
- Fix some typos.
- Use the multi-line comment style as in drivers/vfio.

Changes from V3: https://lore.kernel.org/kvm/20211024083019.232813-1-yishaih@nvidia.com/
vfio/mlx5:
- Align with mlx5 latest specification to create the MKEY with full read
  write permissions.
- Fix unlock ordering in mlx5vf_state_mutex_unlock() to prevent some
  race.

Changes from V2: https://lore.kernel.org/kvm/20211019105838.227569-1-yishaih@nvidia.com/
vfio:
- Put and use the new macro VFIO_DEVICE_STATE_SET_ERROR as Alex asked.
vfio/mlx5:
- Improve/fix state checking as was asked by Alex & Jason.
- Let things be done in a deterministic way upon 'reset_done' following
  the suggested algorithm by Jason.
- Align with mlx5 latest specification when calling the SAVE command.
- Fix some typos.
vdpa/mlx5:
- Drop the patch from the series based on the discussion in the mailing
  list.

Changes from V1: https://lore.kernel.org/kvm/20211013094707.163054-1-yishaih@nvidia.com/
PCI/IOV:
- Add actual interface in the subject as was asked by Bjorn and add
  his Acked-by.
- Move to check explicitly for !dev->is_virtfn as was asked by Alex.
vfio:
- Come with a separate patch for fixing the non-compiled
  VFIO_DEVICE_STATE_SET_ERROR macro.
- Expose vfio_pci_aer_err_detected() to be set by drivers on their own
  pci error handles.
- Add a macro for VFIO_DEVICE_STATE_ERROR in the uapi header file as was
  suggested by Alex.
vfio/mlx5:
- Improve to use xor as part of checking the 'state' change command as
  was suggested by Alex.
- Set state to VFIO_DEVICE_STATE_ERROR when an error occurred instead of
  VFIO_DEVICE_STATE_INVALID.
- Improve state checking as was suggested by Jason.
- Use its own PCI reset_done error handler as was suggested by Jason and
  fix the locking scheme around the state mutex to work properly.

Changes from V0: https://lore.kernel.org/kvm/cover.1632305919.git.leonro@nvidia.com/
PCI/IOV:
- Add an API (i.e. pci_iov_get_pf_drvdata()) that allows SRVIO VF drivers
  to reach the drvdata of a PF.
mlx5_core:
- Add an extra patch to disable SRIOV before PF removal.
- Adapt to use the above PCI/IOV API as part of mlx5_vf_get_core_dev().
- Reuse the exported PCI/IOV virtfn index function call (i.e. pci_iov_vf_id().
vfio:
- Add support in the pci_core to let a driver be notified when
 'reset_done' to let it sets its internal state accordingly.
- Add some helper stuff for 'invalid' state handling.
mlx5_vfio_pci:
- Move to use the 'command mode' instead of the 'state machine'
 scheme as was discussed in the mailing list.
- Handle the RESET scenario when called by vfio_pci_core to sets
 its internal state accordingly.
- Set initial state as RUNNING.
- Put the driver files as sub-folder under drivers/vfio/pci named mlx5
  and update MAINTAINER file as was asked.
vdpa_mlx5:
Add a new patch to use mlx5_vf_get_core_dev() to get PF device.

Jason Gunthorpe (7):
  PCI/IOV: Add pci_iov_vf_id() to get VF index
  PCI/IOV: Add pci_iov_get_pf_drvdata() to allow VF reaching the drvdata
    of a PF
  vfio: Have the core code decode the VFIO_DEVICE_FEATURE ioctl
  vfio: Define device migration protocol v2
  vfio: Extend the device migration protocol with RUNNING_P2P
  vfio: Remove migration protocol v1
  vfio: Extend the device migration protocol with PRE_COPY

Leon Romanovsky (1):
  net/mlx5: Reuse exported virtfn index function call

Yishai Hadas (7):
  net/mlx5: Disable SRIOV before PF removal
  net/mlx5: Expose APIs to get/put the mlx5 core device
  net/mlx5: Introduce migration bits and structures
  vfio/mlx5: Expose migration commands over mlx5 device
  vfio/mlx5: Implement vfio_pci driver for mlx5 devices
  vfio/pci: Expose vfio_pci_core_aer_err_detected()
  vfio/mlx5: Use its own PCI reset_done error handler

 MAINTAINERS                                   |   6 +
 .../net/ethernet/mellanox/mlx5/core/main.c    |  45 ++
 .../ethernet/mellanox/mlx5/core/mlx5_core.h   |   1 +
 .../net/ethernet/mellanox/mlx5/core/sriov.c   |  17 +-
 drivers/pci/iov.c                             |  43 ++
 drivers/vfio/pci/Kconfig                      |   3 +
 drivers/vfio/pci/Makefile                     |   2 +
 drivers/vfio/pci/mlx5/Kconfig                 |  10 +
 drivers/vfio/pci/mlx5/Makefile                |   4 +
 drivers/vfio/pci/mlx5/cmd.c                   | 252 +++++++
 drivers/vfio/pci/mlx5/cmd.h                   |  36 +
 drivers/vfio/pci/mlx5/main.c                  | 664 ++++++++++++++++++
 drivers/vfio/pci/vfio_pci.c                   |   1 +
 drivers/vfio/pci/vfio_pci_core.c              |  97 +--
 drivers/vfio/vfio.c                           | 346 ++++++++-
 include/linux/mlx5/driver.h                   |   3 +
 include/linux/mlx5/mlx5_ifc.h                 | 147 +++-
 include/linux/pci.h                           |  15 +-
 include/linux/vfio.h                          |  43 ++
 include/linux/vfio_pci_core.h                 |   4 +
 include/uapi/linux/vfio.h                     | 516 ++++++++------
 21 files changed, 1946 insertions(+), 309 deletions(-)
 create mode 100644 drivers/vfio/pci/mlx5/Kconfig
 create mode 100644 drivers/vfio/pci/mlx5/Makefile
 create mode 100644 drivers/vfio/pci/mlx5/cmd.c
 create mode 100644 drivers/vfio/pci/mlx5/cmd.h
 create mode 100644 drivers/vfio/pci/mlx5/main.c

-- 
2.18.1