[PATCH v5 00/18] cxl: Add support for powerVM guest​

[Frederic Barrat]

This series adds support for a cxl card in a powerVM guest.

It requires firmware FW840 and an activation code for cxl (CAPI).
Note that pHyp only claims support for cxlflash, and not generic
support for FPGA CAPI accelerators. cxlflash uses the (slightly
modified) Nallatech card, so the memcopy AFU is expected to
work. There's no support for the dedicated mode programming model.

It builds on top of the existing cxl driver for bare-metal. The cxl
module registers either a pci driver or a platform driver, based on
the environment (bare-metal or guest).

The differences in implementation have mostly 2 root causes:
1/ The cxl card is not showing as a PCI device in the device tree over
pHyp. Instead, it is a new type of device found at the root of the
device tree. The AFU description(s) can be found in subfolder(s)
2/ When interacting with the card, the operating system doesn't have
access to the p1 registers, which are the most privileged and reserved
for the hypervisor. It can theoretically access the p2 registers,
though there are hcalls defined for most cases. We only rely on p2
registers for SLB invalidation, for which there is no hcall.

The interactions with the hypervisor are defined in an extension of
the PAPR.

Roughly 3/4 of the code is common between the 2 types of driver. When
the code needs to call a platform-specific implementation, it does so
through an API. The bare-metal and guest implementations each describe
their own definition. See struct cxl_backend_ops.

It has been tested in little-endian and big-endian environments, using
the memcpy and cxlflash AFUs.

The first 3 patches are mostly cleanup and fixes, separating the
bare-metal-specific code from the code which will also be used in a
guest.
Patches 4-8 restructure existing code, to easily add the guest implementation
Patches 9,10 define the interactions with pHyp
Patch 11 prepares the main data structures, separating common and
implementation-specific fields
Patch 12 introduces the core of the guest-specific code
The rest adds smaller, independent changes to better support guests:
sysfs, kernel API, flash of the adapter and failure handling, ...




Changelog:
v4->v5:
 Address comments from Manoj
 - prefer the term 'cxl' over 'capi' throughout the patchset
 - fix some typos in comments and commit messages
 - fix a couple of Coding Style issues
v3->v4:
 Address comments from Ian:
 - patch 3: cxl_psa_map() now fails immediately if context is not attached
 - patch 5: rephrase commit message
 - patch 8: add better comment
 - patch 10: improve pr_devel traces
 - patch 11: rework some error paths
 - patch 12: improve debug traces
 - patch 14: (big) rework of the user API for adapter device
 - patch 16: return EPERM instead of EIO
v2->v3:
 - comment from Ian: external_pe is now an integer
 - add patch 3: the problem state is only defined at attach time when
   using the kernel API, not during context initialization
 - add patch 18: add tracepoints around CAPI hcalls for debugging
v1->v2: (v1 was privately reviewed)
 - integrate comments from Michael Neuling and Ian Munsie
 - add another patch to the series: adapter failure handling
 - base patchset on 4.5-rc1



  cxl: Move common code away from bare-metal-specific files
  cxl: Move bare-metal specific code to specialized files
  cxl: Define process problem state area at attach time only
  cxl: Introduce implementation-specific API
  cxl: Rename some bare-metal specific functions
  cxl: Isolate a few bare-metal-specific calls
  cxl: Update cxl_irq() prototype
  cxl: IRQ allocation for guests
  cxl: New possible return value from hcall
  cxl: New hcalls to support cxl adapters
  cxl: Separate bare-metal fields in adapter and AFU data structures
  cxl: Add guest-specific code
  cxl: sysfs support for guests
  cxl: Support to flash a new image on the adapter from a guest
  cxl: Parse device tree and create cxl device(s) at boot
  cxl: Support the cxl kernel API from a guest
  cxl: Adapter failure handling
  cxl: Add tracepoints around the cxl hcall

 Documentation/ABI/testing/sysfs-class-cxl |    8 +-
 Documentation/powerpc/cxl.txt             |   55 ++
 arch/powerpc/include/asm/hvcall.h         |    1 +
 drivers/misc/cxl/Makefile                 |    1 +
 drivers/misc/cxl/api.c                    |   82 +-
 drivers/misc/cxl/base.c                   |   32 +
 drivers/misc/cxl/context.c                |   11 +-
 drivers/misc/cxl/cxl.h                    |  280 ++++---
 drivers/misc/cxl/debugfs.c                |    4 +
 drivers/misc/cxl/fault.c                  |   25 +-
 drivers/misc/cxl/file.c                   |   28 +-
 drivers/misc/cxl/flash.c                  |  538 +++++++++++++
 drivers/misc/cxl/guest.c                  | 1164 +++++++++++++++++++++++++++++
 drivers/misc/cxl/hcalls.c                 |  648 ++++++++++++++++
 drivers/misc/cxl/hcalls.h                 |  203 +++++
 drivers/misc/cxl/irq.c                    |  309 ++------
 drivers/misc/cxl/main.c                   |  117 ++-
 drivers/misc/cxl/native.c                 |  468 ++++++++++--
 drivers/misc/cxl/of.c                     |  513 +++++++++++++
 drivers/misc/cxl/pci.c                    |  262 +++----
 drivers/misc/cxl/sysfs.c                  |   70 +-
 drivers/misc/cxl/trace.h                  |  193 +++++
 drivers/misc/cxl/vphb.c                   |  158 ++--
 include/misc/cxl.h                        |    5 +
 include/uapi/misc/cxl.h                   |   24 +
 25 files changed, 4475 insertions(+), 724 deletions(-)
 create mode 100644 drivers/misc/cxl/flash.c
 create mode 100644 drivers/misc/cxl/guest.c
 create mode 100644 drivers/misc/cxl/hcalls.c
 create mode 100644 drivers/misc/cxl/hcalls.h
 create mode 100644 drivers/misc/cxl/of.c

-- 
1.9.1