[PATCH v13 02/25] docs: geniezone: Introduce GenieZone hypervisor

[Liju-clr Chen <liju-clr.chen@mediatek.com>]

From: Yingshiuan Pan <yingshiuan.pan@mediatek.com>

GenieZone is MediaTek proprietary hypervisor solution, and it is running
in EL2 stand alone as a type-I hypervisor. It is a pure EL2
implementation which implies it does not rely any specific host VM, and
this behavior improves GenieZone's security as it limits its interface.

Signed-off-by: Yingshiuan Pan <yingshiuan.pan@mediatek.com>
Co-developed-by: Yi-De Wu <yi-de.wu@mediatek.com>
Signed-off-by: Yi-De Wu <yi-de.wu@mediatek.com>
Signed-off-by: Liju Chen <liju-clr.chen@mediatek.com>
---
 Documentation/virt/geniezone/introduction.rst | 87 +++++++++++++++++++
 Documentation/virt/index.rst                  |  1 +
 MAINTAINERS                                   |  6 ++
 3 files changed, 94 insertions(+)
 create mode 100644 Documentation/virt/geniezone/introduction.rst

diff --git a/Documentation/virt/geniezone/introduction.rst b/Documentation/virt/geniezone/introduction.rst
new file mode 100644
index 000000000000..206b019f777b
--- /dev/null
+++ b/Documentation/virt/geniezone/introduction.rst
@@ -0,0 +1,87 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======================
+GenieZone Introduction
+======================
+
+Overview
+========
+GenieZone hypervisor (gzvm) is a type-I hypervisor that supports various virtual
+machine types and provides security features such as TEE-like scenarios and
+secure boot. It can create guest VMs for security use cases and has
+virtualization capabilities for both platform and interrupt. Although the
+hypervisor can be booted independently, it requires the assistance of GenieZone
+hypervisor kernel driver (also named gzvm) to leverage the ability of Linux
+kernel for vCPU scheduling, memory management, inter-VM communication and virtio
+backend support.
+
+Supported Architecture
+======================
+GenieZone now only supports MediaTek ARM64 SoC.
+
+Features
+========
+
+- vCPU Management
+
+  VM manager aims to provide vCPUs on the basis of time sharing on physical
+  CPUs. It requires Linux kernel in host VM for vCPU scheduling and VM power
+  management.
+
+- Memory Management
+
+  Direct use of physical memory from VMs is forbidden and designed to be
+  dictated to the privilege models managed by GenieZone hypervisor for security
+  reason. With the help of the gzvm module, the hypervisor is able to manipulate
+  memory as objects.
+
+- Virtual Platform
+
+  The gzvm hypervisor emulates a virtual mobile platform for guest OS running on
+  guest VM. The platform supports various architecture-defined devices, such as
+  virtual arch timer, GIC, MMIO, PSCI, and exception watching...etc.
+
+- Inter-VM Communication
+
+  Communication among guest VMs is provided mainly on RPC. More communication
+  mechanisms will be provided in the future based on VirtIO-vsock.
+
+- Device Virtualization
+
+  The solution is provided using the well-known VirtIO. The gzvm module redirects
+  MMIO traps back to VMM where the virtual devices are mostly emulated.
+  Ioeventfd is implemented using eventfd for signaling host VM that some IO
+  events in guest VMs need to be processed.
+
+- Interrupt virtualization
+
+  All interrupts during some guest VMs running are handled by GenieZone
+  hypervisor with the help of gzvm module, both virtual and physical ones.
+  In case there's no guest VM running, physical interrupts are handled by host
+  VM directly for performance reason. Irqfd is also implemented using eventfd
+  for accepting vIRQ requests in gzvm module.
+
+Platform architecture component
+===============================
+
+- vm
+
+  The vm component is responsible for setting up the capability and memory
+  management for the protected VMs. The capability is mainly about the lifecycle
+  control and boot context initialization. And the memory management is highly
+  integrated with ARM 2-stage translation tables to convert VA to IPA to PA
+  under proper security measures required by protected VMs.
+
+- vcpu
+
+  The vcpu component is the core of virtualizing an aarch64 physical CPU, and it
+  controls the vCPU lifecycle including creating, running and destroying.
+  With self-defined exit handler, the vm component is able to act accordingly
+  before termination.
+
+- vgic
+
+  The vgic component exposes control interfaces to Linux kernel via irqchip, and
+  we intend to support all SPI, PPI, and SGI. When it comes to virtual
+  interrupts, the GenieZone hypervisor writes to list registers and triggers
+  vIRQ injection in guest VMs via GIC.
diff --git a/Documentation/virt/index.rst b/Documentation/virt/index.rst
index 7fb55ae08598..cf12444db336 100644
--- a/Documentation/virt/index.rst
+++ b/Documentation/virt/index.rst
@@ -16,6 +16,7 @@ Virtualization Support
    coco/sev-guest
    coco/tdx-guest
    hyperv/index
+   geniezone/introduction
 
 .. only:: html and subproject
 
diff --git a/MAINTAINERS b/MAINTAINERS
index 279560bf2b6d..bd119e707b7f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9671,6 +9671,12 @@ F:	include/vdso/
 F:	kernel/time/vsyscall.c
 F:	lib/vdso/
 
+GENIEZONE HYPERVISOR DRIVER
+M:	Yingshiuan Pan <yingshiuan.pan@mediatek.com>
+M:	Ze-Yu Wang <ze-yu.wang@mediatek.com>
+M:	Liju Chen <liju-clr.chen@mediatek.com>
+F:	Documentation/virt/geniezone/
+
 GENWQE (IBM Generic Workqueue Card)
 M:	Frank Haverkamp <haver@linux.ibm.com>
 S:	Supported
-- 
2.18.0