[PATCH 00/15] Introduce /dev/mshv drivers

[Nuno Das Neves]

This series introduces support for creating and running guest machines
while running on the Microsoft Hypervisor. [0]
This is done via an IOCTL interface accessed through /dev/mshv, similar to
/dev/kvm. Another series introducing this support was previously posted.
[1]

These interfaces support VMMs running in:
1. The root patition - provided in the mshv_root module, and
2. VTL 2 - provided in the mshv_vtl module [2]

Patches breakdown
-----------------
The first 7 patches are refactoring and adding some helper functions.
They provide some benefit on their own and could be applied independently
as cleanup patches.

The following 5 patches just set things up for the driver code to come.
These are very small. They are separated so that the remaining patches are
more self-contained.

The final 3 patches are the meat of the series:
- Patch 13 contains new header files used by the driver.
  These are designed to mirror the ABI headers exported by Hyper-V. This is
  done to avoid polluting hyperv-tlfs.h and help track changes to the ABIs
  that are still unstable. (See FAQ below).
- Patch 14 conditionally includes these new header files into mshyperv.h
  and linux/hyperv.h, in order to be able to use these files in the new
  drivers while remaining independent from hyperv-tlfs.h.
- Patch 15 contains the new driver code located in drivers/hv. This is a
  large amount of code and new files, but it is mostly self-contained and
  all within drivers/hv - apart from the IOCTL interface itself in uapi.

FAQ on include/uapi/hyperv/*.h
------------------------------
Q:
Why not just add these definitions to hyperv-tlfs.h?
A:
The intention of hyperv-tlfs.h is to contain stable definitions documented
in the public TLFS document. These new definitions don't fit that criteria,
so they should be separate.

Q:
Why are these files named hvgdk.h, hvgdk_mini.h, hvhdk.h and hvhdk_mini.h?
A:
The precise meaning of the names reflects conventions used internally at
Microsoft.
Naming them this way makes it easy to find where particular Hyper-V
definitions come from, and check their correctness.
It also facilitates the future work of automatically generating these files.

Q:
Why are they in uapi?
A:
In short, to keep things simple. There are many definitions needed in both
the kernel and the VMM in userspace. Separating them doesn't serve much
purpose, and makes it more laborious to import definitions from Hyper-V
code.

Q:
The new headers redefine many things that are already in hyperv-tlfs.h - why?
A:
Some definitions are extended compared to what is documented in the TLFS.
In order to avoid adding undocumented or unstable definitions to hyperv-tlfs.h,
the new headers must compile independently.
Therefore, the new headers must redefine many things in hyperv-tlfs.h in order
to compile.

--------------------------
[0] "Hyper-V" is more well-known, but it really refers to the whole stack
    including the hypervisor and other components that run in Windows
    kernel and userspace.
[1] Previous /dev/mshv patch series and discussion:
    https://lore.kernel.org/linux-hyperv/1632853875-20261-1-git-send-email-nunodasneves@linux.microsoft.com/
[2] Virtual Secure Mode (VSM) and Virtual Trust Levels (VTL):
    https://learn.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/vsm

Nuno Das Neves (15):
  hyperv-tlfs: Change shared HV_REGISTER_* defines to HV_MSR_*
  mshyperv: Introduce hv_get_hypervisor_version
  mshyperv: Introduce numa_node_to_proximity_domain_info
  asm-generic/mshyperv: Introduce hv_recommend_using_aeoi()
  hyperv: Move hv_connection_id to hyperv-tlfs
  hyperv-tlfs: Introduce hv_status_to_string and hv_status_to_errno
  Drivers: hv: Move hv_call_deposit_pages and hv_call_create_vp to
    common code
  Drivers: hv: Introduce per-cpu event ring tail
  Drivers: hv: Introduce hv_output_arg_exists in hv_common
  x86: hyperv: Add mshv_handler irq handler and setup function
  Drivers: hv: export vmbus_isr, hv_context and hv_post_message
  Documentation: Reserve ioctl number for mshv driver
  uapi: hyperv: Add mshv driver headers hvhdk.h, hvhdk_mini.h, hvgdk.h,
    hvgdk_mini.h
  asm-generic: hyperv: Use mshv headers conditionally. Add
    asm-generic/hyperv-defs.h
  Drivers: hv: Add modules to expose /dev/mshv to VMMs running on
    Hyper-V

 .../userspace-api/ioctl/ioctl-number.rst      |    2 +
 arch/arm64/hyperv/mshyperv.c                  |   23 +-
 arch/arm64/include/asm/hyperv-tlfs.h          |   25 +
 arch/arm64/include/asm/mshyperv.h             |    2 +-
 arch/x86/hyperv/hv_init.c                     |    2 +-
 arch/x86/hyperv/hv_proc.c                     |  166 +-
 arch/x86/include/asm/hyperv-tlfs.h            |  137 +-
 arch/x86/include/asm/mshyperv.h               |   13 +-
 arch/x86/kernel/cpu/mshyperv.c                |   71 +-
 drivers/acpi/numa/srat.c                      |    1 +
 drivers/clocksource/hyperv_timer.c            |   24 +-
 drivers/hv/Kconfig                            |   54 +
 drivers/hv/Makefile                           |   21 +
 drivers/hv/hv.c                               |   46 +-
 drivers/hv/hv_call.c                          |  119 +
 drivers/hv/hv_common.c                        |  225 +-
 drivers/hv/hyperv_vmbus.h                     |    2 +-
 drivers/hv/mshv.h                             |  156 ++
 drivers/hv/mshv_eventfd.c                     |  758 +++++++
 drivers/hv/mshv_eventfd.h                     |   80 +
 drivers/hv/mshv_main.c                        |  208 ++
 drivers/hv/mshv_msi.c                         |  129 ++
 drivers/hv/mshv_portid_table.c                |   84 +
 drivers/hv/mshv_root.h                        |  194 ++
 drivers/hv/mshv_root_hv_call.c                | 1064 +++++++++
 drivers/hv/mshv_root_main.c                   | 1964 +++++++++++++++++
 drivers/hv/mshv_synic.c                       |  689 ++++++
 drivers/hv/mshv_vtl.h                         |   52 +
 drivers/hv/mshv_vtl_main.c                    | 1541 +++++++++++++
 drivers/hv/vmbus_drv.c                        |    3 +-
 drivers/hv/xfer_to_guest.c                    |   28 +
 include/asm-generic/hyperv-defs.h             |   26 +
 include/asm-generic/hyperv-tlfs.h             |   77 +-
 include/asm-generic/mshyperv.h                |   76 +-
 include/linux/hyperv.h                        |   11 +-
 include/uapi/hyperv/hvgdk.h                   |   41 +
 include/uapi/hyperv/hvgdk_mini.h              | 1077 +++++++++
 include/uapi/hyperv/hvhdk.h                   | 1352 ++++++++++++
 include/uapi/hyperv/hvhdk_mini.h              |  164 ++
 include/uapi/linux/mshv.h                     |  298 +++
 40 files changed, 10653 insertions(+), 352 deletions(-)
 create mode 100644 drivers/hv/hv_call.c
 create mode 100644 drivers/hv/mshv.h
 create mode 100644 drivers/hv/mshv_eventfd.c
 create mode 100644 drivers/hv/mshv_eventfd.h
 create mode 100644 drivers/hv/mshv_main.c
 create mode 100644 drivers/hv/mshv_msi.c
 create mode 100644 drivers/hv/mshv_portid_table.c
 create mode 100644 drivers/hv/mshv_root.h
 create mode 100644 drivers/hv/mshv_root_hv_call.c
 create mode 100644 drivers/hv/mshv_root_main.c
 create mode 100644 drivers/hv/mshv_synic.c
 create mode 100644 drivers/hv/mshv_vtl.h
 create mode 100644 drivers/hv/mshv_vtl_main.c
 create mode 100644 drivers/hv/xfer_to_guest.c
 create mode 100644 include/asm-generic/hyperv-defs.h
 create mode 100644 include/uapi/hyperv/hvgdk.h
 create mode 100644 include/uapi/hyperv/hvgdk_mini.h
 create mode 100644 include/uapi/hyperv/hvhdk.h
 create mode 100644 include/uapi/hyperv/hvhdk_mini.h
 create mode 100644 include/uapi/linux/mshv.h

-- 
2.25.1