mirror of
https://github.com/projectacrn/acrn-hypervisor.git
synced 2025-07-19 09:53:01 +00:00
doc: rearrange "What is ACRN" for better presentation
What is ACRN introduction dives from the high level architecture directly into the device model and device passthrough information. It gets pretty deep relatively quickly. Move the Static Configuration Based on Scenarios section came earlier in the document. Signed-off-by: David B. Kinder <david.b.kinder@intel.com>
This commit is contained in:
David B. Kinder
David Kinder
parent
26b2b8ca2a
commit
cd60df6382
@ -170,6 +170,127 @@ stopping, and pausing a VM, and pausing or resuming a virtual CPU.
|
||||
See the :ref:`hld-overview` developer reference material for more in-depth
|
||||
information.
|
||||
|
||||
Static Configuration Based on Scenarios
|
||||
***************************************
|
||||
|
||||
Scenarios are a way to describe the system configuration settings of the ACRN
|
||||
hypervisor, VMs, and resources they have access to that meet your specific
|
||||
application's needs such as compute, memory, storage, graphics, networking, and
|
||||
other devices. Scenario configurations are stored in an XML format file and
|
||||
edited using the ACRN Configurator.
|
||||
|
||||
Following a general embedded-system programming model, the ACRN hypervisor is
|
||||
designed to be statically customized at build time per hardware and scenario,
|
||||
rather than providing one binary for all scenarios. Dynamic configuration
|
||||
parsing is not used in the ACRN hypervisor for these reasons:
|
||||
|
||||
* **Reduce complexity**. ACRN is a lightweight reference hypervisor, built for
|
||||
embedded IoT and Edge. As new platforms for embedded systems are rapidly introduced,
|
||||
support for one binary could require more and more complexity in the
|
||||
hypervisor, which is something we strive to avoid.
|
||||
* **Maintain small footprint**. Implementing dynamic parsing introduces hundreds or
|
||||
thousands of lines of code. Avoiding dynamic parsing helps keep the
|
||||
hypervisor's Lines of Code (LOC) in a desirable range (less than 40K).
|
||||
* **Improve boot time**. Dynamic parsing at runtime increases the boot time. Using a
|
||||
static build-time configuration and not dynamic parsing helps improve the boot
|
||||
time of the hypervisor.
|
||||
|
||||
The scenario XML file together with a target board XML file are used to build
|
||||
the ACRN hypervisor image tailored to your hardware and application needs. The ACRN
|
||||
project provides the Board Inspector tool to automatically create the board XML
|
||||
file by inspecting the target hardware. ACRN also provides the
|
||||
:ref:`ACRN Configurator tool <acrn_configuration_tool>`
|
||||
to create and edit a tailored scenario XML file based on predefined sample
|
||||
scenario configurations.
|
||||
|
||||
.. _usage-scenarios:
|
||||
|
||||
Scenario Types
|
||||
**************
|
||||
|
||||
Here are three sample scenario types and diagrams to illustrate how you
|
||||
can define your own configuration scenarios.
|
||||
|
||||
|
||||
* **Shared** is a traditional
|
||||
computing, memory, and device resource sharing
|
||||
model among VMs. The ACRN hypervisor launches the Service VM. The Service VM
|
||||
then launches any post-launched User VMs and provides device and resource
|
||||
sharing mediation through the Device Model. The Service VM runs the native
|
||||
device drivers to access the hardware and provides I/O mediation to the User
|
||||
VMs.
|
||||
|
||||
.. figure:: images/ACRN-industry-example-1-0.75x.png
|
||||
:align: center
|
||||
:name: arch-shared-example
|
||||
|
||||
ACRN High-Level Architecture Shared Example
|
||||
|
||||
Virtualization is especially important in industrial environments because of
|
||||
device and application longevity. Virtualization enables factories to
|
||||
modernize their control system hardware by using VMs to run older control
|
||||
systems and operating systems far beyond their intended retirement dates.
|
||||
|
||||
The ACRN hypervisor needs to run different workloads with little-to-no
|
||||
interference, increase security functions that safeguard the system, run hard
|
||||
real-time sensitive workloads together with general computing workloads, and
|
||||
conduct data analytics for timely actions and predictive maintenance.
|
||||
|
||||
In this example, one post-launched User VM provides Human Machine Interface
|
||||
(HMI) capability, another provides Artificial Intelligence (AI) capability,
|
||||
some compute function is run in the Kata Container, and the RTVM runs the soft
|
||||
Programmable Logic Controller (PLC) that requires hard real-time
|
||||
characteristics.
|
||||
|
||||
- The Service VM provides device sharing functionalities, such as disk and
|
||||
network mediation, to other virtual machines. It can also run an
|
||||
orchestration agent allowing User VM orchestration with tools such as
|
||||
Kubernetes.
|
||||
- The HMI Application OS can be Windows or Linux. Windows is dominant in
|
||||
Industrial HMI environments.
|
||||
- ACRN can support a soft real-time OS such as preempt-rt Linux for soft-PLC
|
||||
control, or a hard real-time OS that offers less jitter.
|
||||
|
||||
* **Partitioned** is a VM resource partitioning model when a User VM requires
|
||||
independence and isolation from other VMs. A partitioned VM's resources are
|
||||
statically configured and are not shared with other VMs. Partitioned User VMs
|
||||
can be Real-Time VMs, Safety VMs, or standard VMs and are launched at boot
|
||||
time by the hypervisor. There is no need for the Service VM or Device Model
|
||||
since all partitioned VMs run native device drivers and directly access their
|
||||
configured resources.
|
||||
|
||||
.. figure:: images/ACRN-partitioned-example-1-0.75x.png
|
||||
:align: center
|
||||
:name: arch-partitioned-example
|
||||
|
||||
ACRN High-Level Architecture Partitioned Example
|
||||
|
||||
This scenario is a simplified configuration showing VM partitioning: both
|
||||
User VMs are independent and isolated, they do not share resources, and both
|
||||
are automatically launched at boot time by the hypervisor. The User VMs can
|
||||
be Real-Time VMs (RTVMs), Safety VMs, or standard User VMs.
|
||||
|
||||
* **Hybrid** scenario simultaneously supports both sharing and partitioning on
|
||||
the consolidated system. The pre-launched (partitioned) User VMs, with their
|
||||
statically configured and unshared resources, are started by the hypervisor.
|
||||
The hypervisor then launches the Service VM. The post-launched (shared) User
|
||||
VMs are started by the Device Model in the Service VM and share the remaining
|
||||
resources.
|
||||
|
||||
.. figure:: images/ACRN-hybrid-rt-example-1-0.75x.png
|
||||
:align: center
|
||||
:name: arch-hybrid-rt-example
|
||||
|
||||
ACRN High-Level Architecture Hybrid-RT Example
|
||||
|
||||
In this Hybrid real-time (RT) scenario, a pre-launched RTVM is started by the
|
||||
hypervisor. The Service VM runs a post-launched User VM that runs non-safety or
|
||||
non-real-time tasks.
|
||||
|
||||
The :ref:`acrn_configuration_tool` tutorial explains how to use the ACRN
|
||||
Configurator to create your own scenario, or to view and modify an existing one.
|
||||
|
||||
|
||||
ACRN Device Model Architecture
|
||||
******************************
|
||||
|
||||
@ -278,129 +399,8 @@ including Xen, KVM, and ACRN hypervisor. In most cases, the User VM OS
|
||||
must be compiled to support passthrough by using kernel
|
||||
build-time options.
|
||||
|
||||
.. _static-configuration-scenarios:
|
||||
.. _static-conmbfiguration-scenarios:
|
||||
|
||||
Static Configuration Based on Scenarios
|
||||
***************************************
|
||||
|
||||
Scenarios are a way to describe the system configuration settings of the ACRN
|
||||
hypervisor, VMs, and resources they have access to that meet your specific
|
||||
application's needs such as compute, memory, storage, graphics, networking, and
|
||||
other devices. Scenario configurations are stored in an XML format file and
|
||||
edited using the ACRN Configurator.
|
||||
|
||||
Following a general embedded-system programming model, the ACRN hypervisor is
|
||||
designed to be statically customized at build time per hardware and scenario,
|
||||
rather than providing one binary for all scenarios. Dynamic configuration
|
||||
parsing is not used in the ACRN hypervisor for these reasons:
|
||||
|
||||
* **Reduce complexity**. ACRN is a lightweight reference hypervisor, built for
|
||||
embedded IoT and Edge. As new platforms for embedded systems are rapidly introduced,
|
||||
support for one binary could require more and more complexity in the
|
||||
hypervisor, which is something we strive to avoid.
|
||||
* **Maintain small footprint**. Implementing dynamic parsing introduces hundreds or
|
||||
thousands of lines of code. Avoiding dynamic parsing helps keep the
|
||||
hypervisor's Lines of Code (LOC) in a desirable range (less than 40K).
|
||||
* **Improve boot time**. Dynamic parsing at runtime increases the boot time. Using a
|
||||
static build-time configuration and not dynamic parsing helps improve the boot
|
||||
time of the hypervisor.
|
||||
|
||||
The scenario XML file together with a target board XML file are used to build
|
||||
the ACRN hypervisor image tailored to your hardware and application needs. The ACRN
|
||||
project provides the Board Inspector tool to automatically create the board XML
|
||||
file by inspecting the target hardware. ACRN also provides the
|
||||
:ref:`ACRN Configurator tool <acrn_configuration_tool>`
|
||||
to create and edit a tailored scenario XML file based on predefined sample
|
||||
scenario configurations.
|
||||
|
||||
.. _usage-scenarios:
|
||||
|
||||
Predefined Sample Scenarios
|
||||
***************************
|
||||
|
||||
Project ACRN provides some predefined sample scenarios to illustrate how you
|
||||
can define your own configuration scenarios.
|
||||
|
||||
|
||||
* **Shared** (called **Industry** in previous releases) is a traditional
|
||||
computing, memory, and device resource sharing
|
||||
model among VMs. The ACRN hypervisor launches the Service VM. The Service VM
|
||||
then launches any post-launched User VMs and provides device and resource
|
||||
sharing mediation through the Device Model. The Service VM runs the native
|
||||
device drivers to access the hardware and provides I/O mediation to the User
|
||||
VMs.
|
||||
|
||||
.. figure:: images/ACRN-industry-example-1-0.75x.png
|
||||
:align: center
|
||||
:name: arch-shared-example
|
||||
|
||||
ACRN High-Level Architecture Shared Example
|
||||
|
||||
Virtualization is especially important in industrial environments because of
|
||||
device and application longevity. Virtualization enables factories to
|
||||
modernize their control system hardware by using VMs to run older control
|
||||
systems and operating systems far beyond their intended retirement dates.
|
||||
|
||||
The ACRN hypervisor needs to run different workloads with little-to-no
|
||||
interference, increase security functions that safeguard the system, run hard
|
||||
real-time sensitive workloads together with general computing workloads, and
|
||||
conduct data analytics for timely actions and predictive maintenance.
|
||||
|
||||
In this example, one post-launched User VM provides Human Machine Interface
|
||||
(HMI) capability, another provides Artificial Intelligence (AI) capability,
|
||||
some compute function is run in the Kata Container, and the RTVM runs the soft
|
||||
Programmable Logic Controller (PLC) that requires hard real-time
|
||||
characteristics.
|
||||
|
||||
- The Service VM provides device sharing functionalities, such as disk and
|
||||
network mediation, to other virtual machines. It can also run an
|
||||
orchestration agent allowing User VM orchestration with tools such as
|
||||
Kubernetes.
|
||||
- The HMI Application OS can be Windows or Linux. Windows is dominant in
|
||||
Industrial HMI environments.
|
||||
- ACRN can support a soft real-time OS such as preempt-rt Linux for soft-PLC
|
||||
control, or a hard real-time OS that offers less jitter.
|
||||
|
||||
* **Partitioned** is a VM resource partitioning model when a User VM requires
|
||||
independence and isolation from other VMs. A partitioned VM's resources are
|
||||
statically configured and are not shared with other VMs. Partitioned User VMs
|
||||
can be Real-Time VMs, Safety VMs, or standard VMs and are launched at boot
|
||||
time by the hypervisor. There is no need for the Service VM or Device Model
|
||||
since all partitioned VMs run native device drivers and directly access their
|
||||
configured resources.
|
||||
|
||||
.. figure:: images/ACRN-partitioned-example-1-0.75x.png
|
||||
:align: center
|
||||
:name: arch-partitioned-example
|
||||
|
||||
ACRN High-Level Architecture Partitioned Example
|
||||
|
||||
This scenario is a simplified configuration showing VM partitioning: both
|
||||
User VMs are independent and isolated, they do not share resources, and both
|
||||
are automatically launched at boot time by the hypervisor. The User VMs can
|
||||
be Real-Time VMs (RTVMs), Safety VMs, or standard User VMs.
|
||||
|
||||
* **Hybrid** scenario simultaneously supports both sharing and partitioning on
|
||||
the consolidated system. The pre-launched (partitioned) User VMs, with their
|
||||
statically configured and unshared resources, are started by the hypervisor.
|
||||
The hypervisor then launches the Service VM. The post-launched (shared) User
|
||||
VMs are started by the Device Model in the Service VM and share the remaining
|
||||
resources.
|
||||
|
||||
.. figure:: images/ACRN-hybrid-rt-example-1-0.75x.png
|
||||
:align: center
|
||||
:name: arch-hybrid-rt-example
|
||||
|
||||
ACRN High-Level Architecture Hybrid-RT Example
|
||||
|
||||
In this Hybrid real-time (RT) scenario, a pre-launched RTVM is started by the
|
||||
hypervisor. The Service VM runs a post-launched User VM that runs non-safety or
|
||||
non-real-time tasks.
|
||||
|
||||
You can find the predefined scenario XML files in the
|
||||
:acrn_file:`misc/config_tools/data` folder in the hypervisor source code. The
|
||||
:ref:`acrn_configuration_tool` tutorial explains how to use the ACRN
|
||||
Configurator to create your own scenario, or to view and modify an existing one.
|
||||
|
||||
Boot Sequence
|
||||
*************
|
||||
|
||||
Loading…
Reference in New Issue
Block a user