[RFC v4 0/8] vfio/hisilicon: add ACC live migration driver

[Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>]

Hi,

This series attempts to add vfio live migration support for
HiSilicon ACC VF devices based on the new v2 migration protocol
definition and mlx5 v7 series discussed here[0]. Many thanks to
everyone involved in the v2 protocol discussions.

Since the v2 protocol is still under discussion, this is provided
as a RFC for now. This migration driver supports only the
VFIO_MIGRATION_STOP_COPY and doesn't have the support for optional
VFIO_MIGRATION_P2P or VFIO_MIGRATION_PRE_COPY features.

Since we are not making use of the PRE_COPY state as used in v1,
the compatibility check for source and destination devices is now
done once the migration data transfer is finished. As discussed
here[1], this is not ideal as it will delay reporting the error
in case of a mismatch.

This is sanity tested on a HiSilicon platform using the Qemu branch
provided here[2].

Please take a look and let know your feedback.

Thanks,
Shameer
[0] https://lore.kernel.org/netdev/20220207172216.206415-1-yishaih@nvidia.com/
[1] https://lore.kernel.org/kvm/20220202103041.2b404d13.alex.williamson@redhat.com/
[2] https://github.com/jgunthorpe/qemu/commits/vfio_migration_v2 


v3 --> RFCv4
-Based on migration v2 protocol and mlx5 v7 series.
-Added RFC tag again as migration v2 protocol is still under discussion.
-Added new patch #6 to retrieve the PF QM data.
-PRE_COPY compatibility check is now done after the migration data
 transfer. This is not ideal and needs discussion.

RFC v2 --> v3
 -Dropped RFC tag as the vfio_pci_core subsystem framework is now
  part of 5.15-rc1.
 -Added override methods for vfio_device_ops read/write/mmap calls
  to limit the access within the functional register space.
 -Patches 1 to 3 are code refactoring to move the common ACC QM
  definitions and header around.

RFCv1 --> RFCv2

 -Adds a new vendor-specific vfio_pci driver(hisi-acc-vfio-pci)
  for HiSilicon ACC VF devices based on the new vfio-pci-core
  framework proposal.

 -Since HiSilicon ACC VF device MMIO space contains both the
  functional register space and migration control register space,
  override the vfio_device_ops ioctl method to report only the
  functional space to VMs.

 -For a successful migration, we still need access to VF dev
  functional register space mainly to read the status registers.
  But accessing these while the Guest vCPUs are running may leave
  a security hole. To avoid any potential security issues, we
  map/unmap the MMIO regions on a need basis and is safe to do so.
  (Please see hisi_acc_vf_ioremap/unmap() fns in patch #4).
 
 -Dropped debugfs support for now.
 -Uses common QM functions for mailbox access(patch #3).

Longfang Liu (2):
  crypto: hisilicon/qm: Move few definitions to common header
  hisi_acc_vfio_pci: Add support for VFIO live migration

Shameer Kolothum (6):
  crypto: hisilicon/qm: Move the QM header to include/linux
  hisi_acc_qm: Move PCI device IDs to common header
  hisi_acc_vfio_pci: add new vfio_pci driver for HiSilicon ACC devices
  hisi_acc_vfio_pci: Restrict access to VF dev BAR2 migration region
  crypto: hisilicon/qm: Add helper to retrieve the PF qm data
  hisi_acc_vfio_pci: Use its own PCI reset_done error handler

 drivers/crypto/hisilicon/hpre/hpre.h          |    2 +-
 drivers/crypto/hisilicon/hpre/hpre_main.c     |   18 +-
 drivers/crypto/hisilicon/qm.c                 |   72 +-
 drivers/crypto/hisilicon/sec2/sec.h           |    2 +-
 drivers/crypto/hisilicon/sec2/sec_main.c      |   20 +-
 drivers/crypto/hisilicon/sgl.c                |    2 +-
 drivers/crypto/hisilicon/zip/zip.h            |    2 +-
 drivers/crypto/hisilicon/zip/zip_main.c       |   17 +-
 drivers/vfio/pci/Kconfig                      |    9 +
 drivers/vfio/pci/Makefile                     |    3 +
 drivers/vfio/pci/hisi_acc_vfio_pci.c          | 1232 +++++++++++++++++
 drivers/vfio/pci/hisi_acc_vfio_pci.h          |  121 ++
 .../qm.h => include/linux/hisi_acc_qm.h       |   44 +
 include/linux/pci_ids.h                       |    6 +
 14 files changed, 1496 insertions(+), 54 deletions(-)
 create mode 100644 drivers/vfio/pci/hisi_acc_vfio_pci.c
 create mode 100644 drivers/vfio/pci/hisi_acc_vfio_pci.h
 rename drivers/crypto/hisilicon/qm.h => include/linux/hisi_acc_qm.h (87%)

-- 
2.17.1