[PATCH v5 00/10] Introduce /dev/mshv root partition driver

Nuno Das Neves
2025-02-26T23:08:58Z

This series introduces support for creating and running guest virtual
machines while running on the Microsoft Hypervisor[0] as root partition.
This is done via an IOCTL interface accessed through /dev/mshv, similar to
/dev/kvm. Another series introducing this support was previously posted in
2021[1], and v4 of this series was last posted in 2023[2].

Patches 1-4 are small refactors and additions to Hyper-V code.
Patches 5-6 just export some definitions needed by /dev/mshv.
Patches 7-9 introduce some functionality and definitions in common code, that
is needed by the driver.
Patch 10 contains the driver code.

-----------------
[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 (2021) and discussion:
https://lore.kernel.org/linux-hyperv/1632853875-20261-1-git-send-email-nunodasneves@linux.microsoft.com/
[2] v4 (2023):
https://lore.kernel.org/linux-hyperv/1696010501-24584-1-git-send-email-nunodasneves@linux.microsoft.com/

-----------------
Changes since v4:
* Slim down the IOCTL interface significantly, via several means:
1. Use generic "passthrough" call MSHV_ROOT_HVCALL to replace many ioctls.
2. Use MSHV_* versions of some of the HV_* definitions.
3. Move hv headers out of uapi altogether, into include/hyperv/, see:
https://lore.kernel.org/linux-hyperv/1732577084-2122-1-git-send-email-nunodasneves@linux.microsoft.com/
* Remove mshv_vtl module altogther, it will be posted in followup series
* Also remove the parent "mshv" module which didn't serve much purpose
* Update and refactor parts of the driver code for clarity, extensibility

Changes since v3 (summarized):
* Clean up the error and debug logging:
1. Add a set of macros vp_*() and partition_*() which call the equivalent
dev_*(), passing the device from the partition struct
* The new macros also print the partition and vp ids to aid debugging
and reduce repeated code
2. Use dev_*() (mostly via the new macros) instead of pr_*() *almost*
everywhere - in interrupt context we can't always get the device struct
3. Remove pr_*() logging from hv_call.c and mshv_root_hv_call.c

Changes since v2 (summarized):
* Fix many checkpatch.pl --strict style issues
* Initialize status in get/set registers hypercall helpers
* Add missing return on error in get_vp_signaled_count

Changes since v1 (summarized):
* Clean up formatting, commit messages

Nuno Das Neves (9):
hyperv: Convert Hyper-V status codes to strings
arm64/hyperv: Add some missing functions to arm64
hyperv: Introduce hv_recommend_using_aeoi()
acpi: numa: Export node_to_pxm()
Drivers/hv: Export some functions for use by root partition module
Drivers: hv: Introduce per-cpu event ring tail
x86: hyperv: Add mshv_handler irq handler and setup function
hyperv: Add definitions for root partition driver to hv headers
Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs

Stanislav Kinsburskii (1):
x86/mshyperv: Add support for extended Hyper-V features

.../userspace-api/ioctl/ioctl-number.rst | 2 +
arch/arm64/hyperv/hv_core.c | 17 +
arch/arm64/hyperv/mshyperv.c | 1 +
arch/arm64/include/asm/mshyperv.h | 12 +
arch/x86/kernel/cpu/mshyperv.c | 16 +-
drivers/acpi/numa/srat.c | 1 +
drivers/hv/Makefile | 5 +-
drivers/hv/hv.c | 12 +-
drivers/hv/hv_common.c | 105 +-
drivers/hv/hv_proc.c | 16 +-
drivers/hv/mshv.h | 30 +
drivers/hv/mshv_common.c | 161 ++
drivers/hv/mshv_eventfd.c | 833 ++++++
drivers/hv/mshv_eventfd.h | 71 +
drivers/hv/mshv_irq.c | 128 +
drivers/hv/mshv_portid_table.c | 84 +
drivers/hv/mshv_root.h | 321 +++
drivers/hv/mshv_root_hv_call.c | 876 +++++++
drivers/hv/mshv_root_main.c | 2329 +++++++++++++++++
drivers/hv/mshv_synic.c | 665 +++++
include/asm-generic/mshyperv.h | 18 +
include/hyperv/hvgdk_mini.h | 64 +-
include/hyperv/hvhdk.h | 132 +-
include/hyperv/hvhdk_mini.h | 91 +
include/uapi/linux/mshv.h | 287 ++
25 files changed, 6248 insertions(+), 29 deletions(-)
create mode 100644 drivers/hv/mshv.h
create mode 100644 drivers/hv/mshv_common.c
create mode 100644 drivers/hv/mshv_eventfd.c
create mode 100644 drivers/hv/mshv_eventfd.h
create mode 100644 drivers/hv/mshv_irq.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 include/uapi/linux/mshv.h

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2.34.1