[PATCH v5 00/13] Drivers for gunyah hypervisor

[Elliot Berman]

Gunyah is a Type-1 hypervisor independent of any
high-level OS kernel, and runs in a higher CPU privilege level. It does
not depend on any lower-privileged OS kernel/code for its core
functionality. This increases its security and can support a much smaller
trusted computing base than a Type-2 hypervisor.

Gunyah is an open source hypervisor. The source repo is available at
https://github.com/quic/gunyah-hypervisor.

The diagram below shows the architecture.

::

         VM A                    VM B
     +-----+ +-----+  | +-----+ +-----+ +-----+
     |     | |     |  | |     | |     | |     |
 EL0 | APP | | APP |  | | APP | | APP | | APP |
     |     | |     |  | |     | |     | |     |
     +-----+ +-----+  | +-----+ +-----+ +-----+
 ---------------------|-------------------------
     +--------------+ | +----------------------+
     |              | | |                      |
 EL1 | Linux Kernel | | |Linux kernel/Other OS |   ...
     |              | | |                      |
     +--------------+ | +----------------------+
 --------hvc/smc------|------hvc/smc------------
     +----------------------------------------+
     |                                        |
 EL2 |            Gunyah Hypervisor           |
     |                                        |
     +----------------------------------------+

Gunyah provides these following features.

- Threads and Scheduling: The scheduler schedules virtual CPUs (VCPUs) on
physical CPUs and enables time-sharing of the CPUs.
- Memory Management: Gunyah tracks memory ownership and use of all memory
under its control. Memory partitioning between VMs is a fundamental
security feature.
- Interrupt Virtualization: All interrupts are handled in the hypervisor
and routed to the assigned VM.
- Inter-VM Communication: There are several different mechanisms provided
for communicating between VMs.
- Device Virtualization: Para-virtualization of devices is supported using
inter-VM communication. Low level system features and devices such as
interrupt controllers are supported with emulation where required.

This series adds the basic framework for detecting that Linux is running
under Gunyah as a virtual machine, communication with the Gunyah Resource
Manager, and a tty driver to demonstrate end-to-end use case of communicating
with RM. Presently, the TTY driver is only capable of behaving as a loopback
device: data sent to ttyGH0 shows up in ttyGH1 and vice versa. More Gunyah
consoles can be exposed as Linux learns about other VMs running in Gunyah.
In a future series, I'll introduce a Gunyah VM loader which can load and run
VMs. This loader will follow the design philosophy of the /dev/kvm.

Changes in v5:
 - Dropped sysfs nodes
 - Switch from aux bus to Gunyah RM bus for the subdevices
 - Cleaning up RM console

Changes in v4: https://lore.kernel.org/all/20220928195633.2348848-1-quic_eberman@xxxxxxxxxxx/
 - Tidied up documentation throughout based on questions/feedback received
 - Switched message queue implementation to use mailboxes
 - Renamed "gunyah_device" as "gunyah_resource"

Changes in v3: https://lore.kernel.org/all/20220811214107.1074343-1-quic_eberman@xxxxxxxxxxx/
 - /Maintained/Supported/ in MAINTAINERS
 - Tidied up documentation throughout based on questions/feedback received
 - Moved hypercalls into arch/arm64/gunyah/; following hyper-v's implementation
 - Drop opaque typedefs
 - Move sysfs nodes under /sys/hypervisor/gunyah/
 - Moved Gunyah console driver to drivers/tty/
 - Reworked gunyah_device design to drop the Gunyah bus.

Changes in v2: https://lore.kernel.org/all/20220801211240.597859-1-quic_eberman@xxxxxxxxxxx/
 - DT bindings clean up
 - Switch hypercalls to follow SMCCC 

v1: https://lore.kernel.org/all/20220223233729.1571114-1-quic_eberman@xxxxxxxxxxx/

Elliot Berman (13):
  docs: gunyah: Introduce Gunyah Hypervisor
  dt-bindings: Add binding for gunyah hypervisor
  gunyah: Common types and error codes for Gunyah hypercalls
  arm64: smccc: Include alternative-macros.h
  virt: gunyah: Add hypercalls to identify Gunyah
  virt: gunyah: Identify hypervisor version
  mailbox: Allow direct registration to a channel
  virt: gunyah: msgq: Add hypercalls to send and receive messages
  mailbox: Add Gunyah message queue mailbox
  gunyah: rsc_mgr: Add resource manager RPC core
  gunyah: rsc_mgr: Add RPC for console services
  gunyah: rsc_mgr: Add subdevices bus
  tty: gunyah: Add tty console driver for RM Console Services

 .../bindings/firmware/gunyah-hypervisor.yaml  |  87 +++
 Documentation/virt/gunyah/index.rst           | 114 ++++
 Documentation/virt/gunyah/message-queue.rst   |  54 ++
 Documentation/virt/index.rst                  |   1 +
 MAINTAINERS                                   |  15 +
 arch/arm64/Kbuild                             |   1 +
 arch/arm64/gunyah/Makefile                    |   2 +
 arch/arm64/gunyah/hypercall.c                 | 104 +++
 drivers/mailbox/Kconfig                       |  10 +
 drivers/mailbox/Makefile                      |   2 +
 drivers/mailbox/gunyah-msgq.c                 | 254 +++++++
 drivers/mailbox/mailbox.c                     |  96 ++-
 drivers/tty/Kconfig                           |   8 +
 drivers/tty/Makefile                          |   1 +
 drivers/tty/gunyah_console.c                  | 439 ++++++++++++
 drivers/virt/Kconfig                          |   1 +
 drivers/virt/Makefile                         |   1 +
 drivers/virt/gunyah/Kconfig                   |  29 +
 drivers/virt/gunyah/Makefile                  |   5 +
 drivers/virt/gunyah/gunyah.c                  |  41 ++
 drivers/virt/gunyah/rsc_mgr.c                 | 644 ++++++++++++++++++
 drivers/virt/gunyah/rsc_mgr.h                 |  66 ++
 drivers/virt/gunyah/rsc_mgr_bus.c             |  84 +++
 drivers/virt/gunyah/rsc_mgr_rpc.c             | 126 ++++
 include/asm-generic/gunyah.h                  | 118 ++++
 include/linux/arm-smccc.h                     |   1 +
 include/linux/gunyah.h                        |  67 ++
 include/linux/gunyah_rsc_mgr.h                |  64 ++
 include/linux/mailbox_client.h                |   1 +
 include/linux/mod_devicetable.h               |   8 +
 scripts/mod/devicetable-offsets.c             |   3 +
 scripts/mod/file2alias.c                      |  10 +
 32 files changed, 2429 insertions(+), 28 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
 create mode 100644 Documentation/virt/gunyah/index.rst
 create mode 100644 Documentation/virt/gunyah/message-queue.rst
 create mode 100644 arch/arm64/gunyah/Makefile
 create mode 100644 arch/arm64/gunyah/hypercall.c
 create mode 100644 drivers/mailbox/gunyah-msgq.c
 create mode 100644 drivers/tty/gunyah_console.c
 create mode 100644 drivers/virt/gunyah/Kconfig
 create mode 100644 drivers/virt/gunyah/Makefile
 create mode 100644 drivers/virt/gunyah/gunyah.c
 create mode 100644 drivers/virt/gunyah/rsc_mgr.c
 create mode 100644 drivers/virt/gunyah/rsc_mgr.h
 create mode 100644 drivers/virt/gunyah/rsc_mgr_bus.c
 create mode 100644 drivers/virt/gunyah/rsc_mgr_rpc.c
 create mode 100644 include/asm-generic/gunyah.h
 create mode 100644 include/linux/gunyah.h
 create mode 100644 include/linux/gunyah_rsc_mgr.h


base-commit: 4fe89d07dcc2804c8b562f6c7896a45643d34b2f
-- 
2.25.1