[v9,vfio,0/7] pds_vfio driver

Message

Brett Creeley April 22, 2023, 1:06 a.m. UTC

This is a patchset for a new vendor specific VFIO driver
(pds_vfio) for use with the AMD/Pensando Distributed Services Card
(DSC). This driver makes use of the newly accepted pds_core
driver, which can be referenced at:

https://lore.kernel.org/netdev/[e-mail]/

This driver will use the pds_core device's adminq as the VFIO
control path to the DSC. In order to make adminq calls, the VFIO
instance makes use of functions exported by the pds_core driver.

In order to receive events from pds_core, the pds_vfio driver
registers to a private notifier. This is needed for various events
that come from the device.

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

                               .------.  .-----------------------.
                               | QEMU |--|  VM  .-------------.  |
                               '......'  |      |   Eth VF    |  |
                                  |      |      .-------------.  |
                                  |      |      |  SR-IOV VF  |  |
                                  |      |      '-------------'  |
                                  |      '------------||---------'
                               .--------------.       ||
                               |/dev/<vfio_fd>|       ||
                               '--------------'       ||
Host Userspace                         |              ||
===================================================   ||
Host Kernel                            |              ||
                                  .--------.          ||
                                  |vfio-pci|          ||
                                  '--------'          ||
       .------------------.           ||              ||
       |   | exported API |<----+     ||              ||
       |   '--------------|     |     ||              ||
       |                  |    .-------------.        ||
       |     pds_core     |--->|   pds_vfio  |        ||
       '------------------' |  '-------------'        ||
               ||           |         ||              ||
             09:00.0     notifier    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:

v9:
- Various fixes/suggestions by Alex Williamson
	- Fix how ID is generated in client registration
	- Add helper functions to get the VF's struct device and struct
	  pci_dev pointers instead of caching the struct pci dev
	- Remove redundant pds_vfio_lm_state() function and remove any
	  places this was being called
	- Fix multi-line comments to follow standard convention
	- Remove confusing comments in
	  pds_vfio_step_device_state_locked() since the driver's
	  migration states align with the VFIO documentation
	- Validate pdsc returned from pdsc_get_pf_struct()
- Various fixes/suggestions by Jason Gunthorpe
	- Use struct pdsc instead of void *
	- Use {} instead of {0} for structure initialization
	- Use unions on the stack instead of casting to the union when
	  sending AQ commands, which required including pds_lm.h in
	  pds_adminq.h
	- Replace use of dma_alloc_coherent() when creating the sgl DMA
	  entries for the LM file
	- Remove cached struct device *coredev and instead use
	  pci_physfn() to get the pds_core's struct device pointer
	- Drop the recovery work item and call pds_vfio_recovery()
	  directly from the notifier callback
	- Remove unnecessary #define for "pds_vfio_lm" and just use the
	  string inline to the anon_inode_getfile() argument
- Fix LM file reference counting
- Move initialization of some struct members to when the struct is being
  initialized for AQ commands
- Make use of GFP_KERNEL_ACCOUNT where it makes sense
- Replace PDS_VFIO_DRV_NAME with KBUILD_MODNAME
- Update to latest pds_core exported functions
- Remove duplicated prototypes for
  pds_vfio_dma_logging_[start|stop|report] from lm.h
- Hold pds_vfio->state_mutex while starting, stopping, and reporting
  dirty page tracking in pds_vfio_dma_logging_[start|stop|report]
- Remove duplicate PDS_DEV_TYPE_LM_STR define from pds_lm.h that's
  already included in pds_common.h
- Replace use of dma_alloc_coherent() when creating the sgl DMA
  entries for the dirty bitmaps

v8:
https://lore.kernel.org/netdev/[e-mail]/
- provide default iommufd callbacks for bind_iommufd, unbind_iommufd, and
  attach_ioas for the VFIO device as suggested by Shameerali Kolothum
  Thodi

v7:
https://lore.kernel.org/netdev/[e-mail]/
- Disable and clean up dirty page tracking when the VFIO device is closed
- Various improvements suggested by Simon Horman:
	- Fix RCT in vfio_combine_iova_ranges()
	- Simplify function exit paths by removing unnecessary goto
	  labels
	- Cleanup pds_vifo_print_guest_region_info() by adding a goto
	  label for freeing memory, which allowed for reduced
	  indentation on a for loop
	- Where possible use C99 style for loops

v6:
https://lore.kernel.org/netdev/[e-mail]/
- As suggested by Alex Williamson, use pci_domain_nr() macro to make sure
  the pds_vfio client's devname is unique
- Remove unnecessary forward declaration and include
- Fix copyright comment to use correct company name
- Remove "." from struct documentation for consistency

v5:
https://lore.kernel.org/netdev/[e-mail]/
- Fix SPDX comments in .h files
- Remove adminqcq argument from pdsc_post_adminq() uses
- Unregister client on vfio_pci_core_register_device() failure
- Other minor checkpatch issues

v4:
https://lore.kernel.org/netdev/[e-mail]/
- Update cover letter ASCII diagram to reflect new driver architecture
- Remove auxiliary driver implementation
- Use pds_core's exported functions to communicate with the device
- Implement and register notifier for events from the device/pds_core
- Use module_pci_driver() macro since auxiliary driver configuration is
  no longer needed in __init/__exit

v3:
https://lore.kernel.org/netdev/[e-mail]/
- 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/[e-mail]/
- 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/[e-mail]/

Brett Creeley (7):
  vfio: Commonize combine_ranges for use in other VFIO drivers
  vfio/pds: Initial support for pds_vfio VFIO driver
  vfio/pds: register with the pds_core PF
  vfio/pds: Add VFIO live migration support
  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  |  79 +++
 .../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                  |  20 +
 drivers/vfio/pci/pds/Makefile                 |  11 +
 drivers/vfio/pci/pds/cmds.c                   | 487 +++++++++++++++
 drivers/vfio/pci/pds/cmds.h                   |  25 +
 drivers/vfio/pci/pds/dirty.c                  | 562 ++++++++++++++++++
 drivers/vfio/pci/pds/dirty.h                  |  45 ++
 drivers/vfio/pci/pds/lm.c                     | 436 ++++++++++++++
 drivers/vfio/pci/pds/lm.h                     |  41 ++
 drivers/vfio/pci/pds/pci_drv.c                | 214 +++++++
 drivers/vfio/pci/pds/pci_drv.h                |   9 +
 drivers/vfio/pci/pds/vfio_dev.c               | 248 ++++++++
 drivers/vfio/pci/pds/vfio_dev.h               |  46 ++
 drivers/vfio/vfio_main.c                      |  47 ++
 include/linux/pds/pds_adminq.h                |  17 +
 include/linux/pds/pds_lm.h                    | 390 ++++++++++++
 include/linux/vfio.h                          |   3 +
 22 files changed, 2693 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/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