[GIT PULL] Add mlx5 live migration driver and v2 migration protocol

* [GIT PULL] Add mlx5 live migration driver and v2 migration protocol
@ 2022-03-03 11:29 Leon Romanovsky
  0 siblings, 0 replies; 4+ messages in thread
From: Leon Romanovsky @ 2022-03-03 11:29 UTC (permalink / raw)
  To: alex.williamson, bhelgaas, jgg, saeedm
  Cc: Leon Romanovsky, Yishai Hadas, linux-pci, kvm, netdev, kuba,
	kwankhede, mgurtovoy, maorg, cohuck, ashok.raj, kevin.tian,
	shameerali.kolothum.thodi

From: Leon Romanovsky <leonro@nvidia.com>

Hi Alex,

This pull request contains the v9 version of recently submitted mlx5 live migration
driver from Yishai and Jason.

In addition to changes in VFIO, this series extended the ethernet part of mlx5 driver.
Such changes have all chances to create merge conflicts between VFIO, netdev and RDMA
subsystems, which are eliminated with this PR.

This is v10 version with added ROB tags and two small changes in documentation.
 
 * Patch #8:

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index f1b5d231b7ed..66dda06ec42d 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -56,7 +56,7 @@ struct vfio_device {
  * @match: Optional device name match callback (return: 0 for no-match, >0 for
  *         match, -errno for abort (ex. match with insufficient or incorrect
  *         additional args)
- * @device_feature: Fill in the VFIO_DEVICE_FEATURE ioctl
+ * @device_feature: Optional, fill in the VFIO_DEVICE_FEATURE ioctl
  * @migration_set_state: Optional callback to change the migration state for
  *         devices that support migration. It's mandatory for
  *         VFIO_DEVICE_FEATURE_MIGRATION migration support.


  * Patch #10:

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index bdb5205bb358..a4555014bd1e 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1579,8 +1579,8 @@ int vfio_mig_get_next_state(struct vfio_device *device,
{
        enum { VFIO_DEVICE_NUM_STATES = VFIO_DEVICE_STATE_RUNNING_P2P + 1 };
        /*
-        * The coding in this table requires the driver to implement
-        * FSM arcs:
+        * The coding in this table requires the driver to implement the
+        * following FSM arcs:
         *         RESUMING -> STOP
         *         STOP -> RESUMING
         *         STOP -> STOP_COPY
@@ -1596,8 +1596,9 @@ int vfio_mig_get_next_state(struct vfio_device *device,
         *         RUNNING -> STOP
         *         STOP -> RUNNING
         *
-        * If all optional features are supported then the coding will step
-        * through multiple states for these combination transitions:
+        * The coding will step through multiple states for some combination
+        * transitions; if all optional features are supported, this means the
+        * following ones:
         *         RESUMING -> STOP -> RUNNING_P2P
         *         RESUMING -> STOP -> RUNNING_P2P -> RUNNING
         *         RESUMING -> STOP -> STOP_COPY

Thanks

------------------------------------------------------------------------------------
The following changes since commit cfb92440ee71adcc2105b0890bb01ac3cddb8507:

  Linux 5.17-rc5 (2022-02-20 13:07:20 -0800)

are available in the Git repository at:

  https://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux.git tags/mlx5-vfio-v10

for you to fetch changes up to 88faa5e8ead62a2a559b1246bba7aa982fde7c67:

  vfio/mlx5: Use its own PCI reset_done error handler (2022-03-03 13:01:19 +0200)

----------------------------------------------------------------
Add mlx5 live migration driver and v2 migration protocol

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

Link: https://lore.kernel.org/all/20220224142024.147653-1-yishaih@nvidia.com
Signed-of-by: Leon Romanovsky <leonro@nvidia.com>

----------------------------------------------------------------
Jason Gunthorpe (6):
      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 documentation

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

Yishai Hadas (8):
      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
      net/mlx5: Add migration commands definitions
      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 +
 drivers/net/ethernet/mellanox/mlx5/core/cmd.c      |  10 +
 drivers/net/ethernet/mellanox/mlx5/core/main.c     |  45 ++
 .../net/ethernet/mellanox/mlx5/core/mlx5_core.h    |   1 +
 drivers/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                        | 259 ++++++++
 drivers/vfio/pci/mlx5/cmd.h                        |  36 ++
 drivers/vfio/pci/mlx5/main.c                       | 676 +++++++++++++++++++++
 drivers/vfio/pci/vfio_pci.c                        |   1 +
 drivers/vfio/pci/vfio_pci_core.c                   | 101 ++-
 drivers/vfio/vfio.c                                | 296 ++++++++-
 include/linux/mlx5/driver.h                        |   3 +
 include/linux/mlx5/mlx5_ifc.h                      | 147 ++++-
 include/linux/pci.h                                |  15 +-
 include/linux/vfio.h                               |  53 ++
 include/linux/vfio_pci_core.h                      |   4 +
 include/uapi/linux/vfio.h                          | 406 ++++++-------
 22 files changed, 1847 insertions(+), 291 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

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