OvmfPkg/VirtioFsDxe: add EFI_FILE_INFO cache fields to VIRTIO_FS_FILE

[mirror_edk2.git] / DynamicTablesPkg / Readme.md

# Dynamic Tables Framework\r
\r
Dynamic Tables Framework provides mechanisms to reduce the amount\r
of effort required in porting firmware to new platforms. The aim is\r
to provide an implementation capable of generating the firmware\r
tables from an external source.  This is potentially a management\r
node, either local or remote, or, where suitable, a file that might\r
be generated from the system construction.  This initial release\r
does not fully implement that - the configuration is held in local\r
UEFI modules.\r
\r
# Feature Summary\r
\r
The dynamic tables framework is designed to generate standardised\r
firmware tables that describe the hardware information at\r
run-time. A goal of standardised firmware is to have a common\r
firmware for a platform capable of booting both Windows and Linux\r
operating systems.\r
\r
Traditionally the firmware tables are handcrafted using ACPI\r
Source Language (ASL), Table Definition Language (TDL) and\r
C-code. This approach can be error prone and involves time\r
consuming debugging. In addition, it may be desirable to configure\r
platform hardware at runtime such as: configuring the number of\r
cores available for use by the OS, or turning SoC features ON or\r
OFF.\r
\r
The dynamic tables framework simplifies this by providing a set\r
of standard table generators, that are implemented as libraries.\r
These generators query a platform specific component, the\r
'Configuration Manager', to collate the information required\r
for generating the tables at run-time.\r
\r
The framework also provides the ability to implement custom/OEM\r
generators; thereby facilitating support for custom tables. The\r
custom generators can also utilize the existing standard generators\r
and override any functionality if needed.\r
\r
The framework currently implements a set of standard ACPI table\r
generators for ARM architecture, that can generate Server Base Boot\r
Requirement (SBBR) compliant tables. Although, the set of standard\r
generators implement the functionality required for ARM architecture;\r
the framework is extensible, and support for other architectures can\r
be added easily.\r
\r
The framework currently supports the following table generators for ARM:\r
* DBG2 - Debug Port Table 2\r
* DSDT - Differentiated system description table. This is essentially\r
         a RAW table generator.\r
* FADT - Fixed ACPI Description Table\r
* GTDT - Generic Timer Description Table\r
* IORT - IO Remapping Table\r
* MADT - Multiple APIC Description Table\r
* MCFG - PCI Express memory mapped configuration space base address\r
         Description Table\r
* SPCR - Serial Port Console Redirection Table\r
* SSDT - Secondary System Description Table. This is essentially\r
         a RAW table generator.\r
\r
## Dynamic AML\r
\r
ACPI Definition block (e.g. DSDT or SSDT) tables are used to describe system\r
devices along with other control and power management information. These tables\r
are written using ACPI Source Language (ASL). The ASL code is compiled using an\r
ASL compiler (e.g. Intel iASL compiler) to generate ACPI Machine Language (AML)\r
bytecode.\r
\r
Since, definition blocks are represented using AML grammar, run-time generation\r
of definition blocks is complex. Dynamic AML is a feature of Dynamic Tables\r
framework that provides a solution for dynamic generation of ACPI Definition\r
block tables.\r
\r
Dynamic AML introduces the following techniques:\r
* AML Fixup\r
* AML Codegen\r
* AML Fixup + Codegen\r
\r
### AML Fixup\r
AML fixup is a technique that involves compiling an ASL template file to\r
generate AML bytecode. This template AML bytecode can be parsed at run-time\r
and a fixup code can update the required fields in the AML template.\r
\r
To simplify AML Fixup, the Dynamic Tables Framework provides an *AmlLib*\r
library with a rich set of APIs that can be used to fixup the AML code.\r
\r
### AML Codegen\r
AML Codegen employs generating small segments of AML code. The *AmlLib*\r
library provides AML Codegen APIs that generate the AML code segments.\r
\r
    Example: The following table depicts the AML Codegen APIs and the\r
             corresponding ASL code that would be generated.\r
\r
    | AML Codegen API                | ASL Code                       |\r
    |--------------------------------|--------------------------------|\r
    |  AmlCodeGenDefinitionBlock (   |  DefinitionBlock (             |\r
    |    ..,                         |    ...                         |\r
    |    &RootNode);                 |  ) {                           |\r
    |  AmlCodeGenScope (             |    Scope (_SB) {               |\r
    |    "\_SB",                     |                                |\r
    |    RootNode,                   |                                |\r
    |    &ScopeNode);                |                                |\r
    |  AmlCodeGenDevice (            |    Device (CPU0) {             |\r
    |    "CPU0",                     |                                |\r
    |    ScopeNode,                  |                                |\r
    |    &CpuNode);                  |                                |\r
    |  AmlCodeGenNameString (        |      Name (_HID, "ACPI0007")   |\r
    |    "_HID",                     |                                |\r
    |    "ACPI0007",                 |                                |\r
    |    CpuNode,                    |                                |\r
    |    &HidNode);                  |                                |\r
    |  AmlCodeGenNameInteger (       |      Name (_UID, Zero)         |\r
    |    "_UID",                     |                                |\r
    |    0,                          |                                |\r
    |    CpuNode,                    |                                |\r
    |    &UidNode);                  |                                |\r
    |                                |      } // Device               |\r
    |                                |    } // Scope                  |\r
    |                                |  } // DefinitionBlock          |\r
\r
### AML Fixup + Codegen\r
A combination of AML Fixup and AML Codegen could be used for generating\r
Definition Blocks. For example the AML Fixup could be used to fixup certain\r
parts of the AML template while the AML Codegen APIs could be used to inserted\r
small fragments of AML code in the AML template.\r
\r
### AmlLib Library\r
Since, AML bytecode represents complex AML grammar, an **AmlLib** library is\r
introduced to assist parsing and traversing of the AML bytecode at run-time.\r
\r
The AmlLib library parses a definition block and represents it as an AML\r
tree. This tree representation is based on the AML grammar defined by the\r
ACPI 6.3 specification, section - 20 'ACPI Machine Language (AML)\r
Specification'.\r
\r
AML objects, methods and data are represented as tree nodes. Since the AML\r
data is represented as tree nodes, it is possible to traverse the tree, locate\r
a node and modify the node data. The tree can then be serialized to a buffer\r
(that represents the definition block). This definition block containing\r
the fixed up AML code can then be installed as an ACPI table (DSDT/SSDT).\r
\r
AmlLib provides a rich API to operate on AML data. For example it provides\r
APIs to update a device's name, the value of a "_UID" object, and the memory\r
and interrupt number stored in a "_CRS" node.\r
\r
Although the AmlLib performs checks to a reasonable extent while modifying a\r
definition block, these checks may not cover all aspects due to the complexity\r
of the ASL/AML language. It is therefore recommended to review any operation\r
performed, and validate the generated output.\r
\r
    Example: The serialized AML code could be validated by\r
     - Saving the generated AML to a file and comparing with\r
       a reference output.\r
     or\r
     - Disassemble the generated AML using the iASL compiler\r
       and verifying the output.\r
\r
# Roadmap\r
\r
The current implementation of the Configuration Manager populates the\r
platform information statically as a C structure. Further enhancements\r
to introduce runtime loading of platform information from a platform\r
information file is planned.\r
\r
Also support for generating SMBIOS tables is planned and will be added\r
subsequently.\r
\r
# Supported Platforms\r
\r
1. Juno\r
2. FVP Models\r
\r
# Build Instructions\r
\r
1. Set path for the iASL compiler with support for generating a C header\r
   file as output.\r
\r
2. Set PACKAGES_PATH to point to the locations of the following repositories:\r
\r
Example:\r
\r
> set PACKAGES_PATH=%CD%\edk2;%CD%\edk2-platforms;\r
\r
  or\r
\r
> export PACKAGES_PATH=$PWD/edk2:$PWD/edk2-platforms\r
\r
3. To enable Dynamic tables framework the *'DYNAMIC_TABLES_FRAMEWORK'*\r
option must be defined. This can be passed as a command line\r
parameter to the edk2 build system.\r
\r
Example:\r
\r
>build -a AARCH64 -p Platform\ARM\JunoPkg\ArmJuno.dsc\r
   -t GCC5 **-D DYNAMIC_TABLES_FRAMEWORK**\r
\r
or\r
\r
>build -a AARCH64 -p Platform\ARM\VExpressPkg\ArmVExpress-FVP-AArch64.dsc\r
   -t GCC5 **-D DYNAMIC_TABLES_FRAMEWORK**\r
\r
# Prerequisites\r
\r
Ensure that the latest ACPICA iASL compiler is used for building *Dynamic Tables Framework*.\r
*Dynamic Tables Framework* has been tested using the following iASL compiler version:\r
[Version 20200717](https://www.acpica.org/node/183), dated 17 July, 2020.\r
\r
\r
#Running CI builds locally\r
\r
The TianoCore EDKII project has introduced Core CI infrastructure using TianoCore EDKII Tools PIP modules:\r
\r
   -  *[edk2-pytool-library](https://pypi.org/project/edk2-pytool-library)*\r
\r
   - *[edk2-pytool-extensions](https://pypi.org/project/edk2-pytool-extensions)*\r
\r
\r
The instructions to setup the CI environment are in *'edk2\\.pytool\\Readme.md'*\r
\r
## Building DynamicTablesPkg with Pytools\r
\r
1. [Optional] Create a Python Virtual Environment - generally once per workspace\r
\r
    ```\r
        python -m venv <name of virtual environment>\r
\r
        e.g. python -m venv edk2-ci\r
    ```\r
\r
2. [Optional] Activate Virtual Environment - each time new shell/command window is opened\r
\r
    ```\r
        <name of virtual environment>/Scripts/activate\r
\r
        e.g. On a windows host PC run:\r
             edk2-ci\Scripts\activate.bat\r
    ```\r
3. Install Pytools - generally once per virtual env or whenever pip-requirements.txt changes\r
\r
    ```\r
        pip install --upgrade -r pip-requirements.txt\r
    ```\r
\r
4. Initialize & Update Submodules - only when submodules updated\r
\r
    ```\r
        stuart_setup -c .pytool/CISettings.py TOOL_CHAIN_TAG=<TOOL_CHAIN_TAG> -a <TARGET_ARCH>\r
\r
        e.g. stuart_setup -c .pytool/CISettings.py TOOL_CHAIN_TAG=GCC5\r
    ```\r
\r
5. Initialize & Update Dependencies - only as needed when ext_deps change\r
\r
    ```\r
        stuart_update -c .pytool/CISettings.py TOOL_CHAIN_TAG=<TOOL_CHAIN_TAG> -a <TARGET_ARCH>\r
\r
        e.g. stuart_update -c .pytool/CISettings.py TOOL_CHAIN_TAG=GCC5\r
    ```\r
\r
6. Compile the basetools if necessary - only when basetools C source files change\r
\r
    ```\r
        python BaseTools/Edk2ToolsBuild.py -t <ToolChainTag>\r
    ```\r
\r
7. Compile DynamicTablesPkg\r
\r
    ```\r
        stuart_build-c .pytool/CISettings.py TOOL_CHAIN_TAG=<TOOL_CHAIN_TAG> -a <TARGET_ARCH>\r
\r
        e.g. stuart_ci_build -c .pytool/CISettings.py TOOL_CHAIN_TAG=GCC5 -p DynamicTablesPkg -a AARCH64 --verbose\r
    ```\r
\r
    - use `stuart_build -c .pytool/CISettings.py -h` option to see help on additional options.\r
\r
\r
# Documentation\r
\r
Refer to the following presentation from *UEFI Plugfest Seattle 2018*:\r
\r
[Dynamic Tables Framework: A Step Towards Automatic Generation of Advanced Configuration and Power Interface (ACPI) & System Management BIOS (SMBIOS) Tables](http://www.uefi.org/sites/default/files/resources/Arm_Dynamic%20Tables%20Framework%20A%20Step%20Towards%20Automatic%20Generation%20of%20Advanced%20Configuration%20and%20Power%20Interface%20%28ACPI%29%20%26%20System%20Management%20BIOS%20%28SMBIOS%29%20Tables%20_0.pdf)\r
\r