| ======== |
| Codebase |
| ======== |
| |
| This section presents the various parts of QEMU and how the codebase is |
| organized. |
| |
| Beyond giving succinct descriptions, the goal is to offer links to various |
| parts of the documentation/codebase. |
| |
| Subsystems |
| ---------- |
| |
| An exhaustive list of subsystems and associated files can be found in the |
| `MAINTAINERS <https://gitlab.com/qemu-project/qemu/-/blob/master/MAINTAINERS>`_ |
| file. |
| |
| Some of the main QEMU subsystems are: |
| |
| - `Accelerators<Accelerators>` |
| - Block devices and `disk images<disk images>` support |
| - `CI<ci>` and `Tests<testing>` |
| - `Devices<device-emulation>` & Board models |
| - `Documentation <documentation-root>` |
| - `GDB support<GDB usage>` |
| - :ref:`Migration<migration>` |
| - `Monitor<QEMU monitor>` |
| - :ref:`QOM (QEMU Object Model)<qom>` |
| - `System mode<System emulation>` |
| - :ref:`TCG (Tiny Code Generator)<tcg>` |
| - `User mode<user-mode>` (`Linux<linux-user-mode>` & `BSD<bsd-user-mode>`) |
| - User Interfaces |
| |
| More documentation on QEMU subsystems can be found on :ref:`internal-subsystem` |
| page. |
| |
| The Grand tour |
| -------------- |
| |
| We present briefly here what every folder in the top directory of the codebase |
| contains. Hop on! |
| |
| The folder name links here will take you to that folder in our gitlab |
| repository. Other links will take you to more detailed documentation for that |
| subsystem, where we have it. Unfortunately not every subsystem has documentation |
| yet, so sometimes the source code is all you have. |
| |
| * `accel <https://gitlab.com/qemu-project/qemu/-/tree/master/accel>`_: |
| Infrastructure and architecture agnostic code related to the various |
| `accelerators <Accelerators>` supported by QEMU |
| (TCG, KVM, hvf, whpx, xen, nvmm). |
| Contains interfaces for operations that will be implemented per |
| `target <https://gitlab.com/qemu-project/qemu/-/tree/master/target>`_. |
| * `audio <https://gitlab.com/qemu-project/qemu/-/tree/master/audio>`_: |
| Audio (host) support. |
| * `authz <https://gitlab.com/qemu-project/qemu/-/tree/master/authz>`_: |
| `QEMU Authorization framework<client authorization>`. |
| * `backends <https://gitlab.com/qemu-project/qemu/-/tree/master/backends>`_: |
| Various backends that are used to access resources on the host (e.g. for |
| random number generation, memory backing or cryptographic functions). |
| * `block <https://gitlab.com/qemu-project/qemu/-/tree/master/block>`_: |
| Block devices and `image formats<disk images>` implementation. |
| * `bsd-user <https://gitlab.com/qemu-project/qemu/-/tree/master/bsd-user>`_: |
| `BSD User mode<bsd-user-mode>`. |
| * build: Where the code built goes by default. You can tell the QEMU build |
| system to put the built code anywhere else you like. |
| * `chardev <https://gitlab.com/qemu-project/qemu/-/tree/master/chardev>`_: |
| Various backends used by char devices. |
| * `common-user <https://gitlab.com/qemu-project/qemu/-/tree/master/common-user>`_: |
| User-mode assembly code for dealing with signals occurring during syscalls. |
| * `configs <https://gitlab.com/qemu-project/qemu/-/tree/master/configs>`_: |
| Makefiles defining configurations to build QEMU. |
| * `contrib <https://gitlab.com/qemu-project/qemu/-/tree/master/contrib>`_: |
| Community contributed devices/plugins/tools. |
| * `crypto <https://gitlab.com/qemu-project/qemu/-/tree/master/crypto>`_: |
| Cryptographic algorithms used in QEMU. |
| * `disas <https://gitlab.com/qemu-project/qemu/-/tree/master/disas>`_: |
| Disassembly functions used by QEMU target code. |
| * `docs <https://gitlab.com/qemu-project/qemu/-/tree/master/docs>`_: |
| QEMU Documentation. |
| * `dump <https://gitlab.com/qemu-project/qemu/-/tree/master/dump>`_: |
| Code to dump memory of a running VM. |
| * `ebpf <https://gitlab.com/qemu-project/qemu/-/tree/master/ebpf>`_: |
| eBPF program support in QEMU. `virtio-net RSS<ebpf-rss>` uses it. |
| * `fpu <https://gitlab.com/qemu-project/qemu/-/tree/master/fpu>`_: |
| Floating-point software emulation. |
| * `fsdev <https://gitlab.com/qemu-project/qemu/-/tree/master/fsdev>`_: |
| `VirtFS <https://www.linux-kvm.org/page/VirtFS>`_ support. |
| * `gdbstub <https://gitlab.com/qemu-project/qemu/-/tree/master/gdbstub>`_: |
| `GDB <GDB usage>` support. |
| * `gdb-xml <https://gitlab.com/qemu-project/qemu/-/tree/master/gdb-xml>`_: |
| Set of XML files describing architectures and used by `gdbstub <GDB usage>`. |
| * `host <https://gitlab.com/qemu-project/qemu/-/tree/master/host>`_: |
| Various architecture specific header files (crypto, atomic, memory |
| operations). |
| * `linux-headers <https://gitlab.com/qemu-project/qemu/-/tree/master/linux-headers>`_: |
| A subset of headers imported from Linux kernel and used for implementing |
| KVM support and user-mode. |
| * `linux-user <https://gitlab.com/qemu-project/qemu/-/tree/master/linux-user>`_: |
| `User mode <user-mode>` implementation. Contains one folder per target |
| architecture. |
| * `.gitlab-ci.d <https://gitlab.com/qemu-project/qemu/-/tree/master/.gitlab-ci.d>`_: |
| `CI <ci>` yaml and scripts. |
| * `include <https://gitlab.com/qemu-project/qemu/-/tree/master/include>`_: |
| All headers associated to different subsystems in QEMU. The hierarchy used |
| mirrors source code organization and naming. |
| * `hw <https://gitlab.com/qemu-project/qemu/-/tree/master/hw>`_: |
| `Devices <device-emulation>` and boards emulation. Devices are categorized by |
| type/protocol/architecture and located in associated subfolder. |
| * `io <https://gitlab.com/qemu-project/qemu/-/tree/master/io>`_: |
| QEMU `I/O channels <https://lists.gnu.org/archive/html/qemu-devel/2015-11/msg04208.html>`_. |
| * `libdecnumber <https://gitlab.com/qemu-project/qemu/-/tree/master/libdecnumber>`_: |
| Import of gcc library, used to implement decimal number arithmetic. |
| * `migration <https://gitlab.com/qemu-project/qemu/-/tree/master/migration>`__: |
| :ref:`Migration framework <migration>`. |
| * `monitor <https://gitlab.com/qemu-project/qemu/-/tree/master/monitor>`_: |
| `Monitor <QEMU monitor>` implementation (HMP & QMP). |
| * `nbd <https://gitlab.com/qemu-project/qemu/-/tree/master/nbd>`_: |
| QEMU NBD (Network Block Device) server. |
| * `net <https://gitlab.com/qemu-project/qemu/-/tree/master/net>`_: |
| Network (host) support. |
| * `pc-bios <https://gitlab.com/qemu-project/qemu/-/tree/master/pc-bios>`_: |
| Contains pre-built firmware binaries and boot images, ready to use in |
| QEMU without compilation. |
| * `plugins <https://gitlab.com/qemu-project/qemu/-/tree/master/plugins>`_: |
| :ref:`TCG plugins <tcg-plugins>` core implementation. Plugins can be found in |
| `tests <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/tcg/plugins>`__ |
| and `contrib <https://gitlab.com/qemu-project/qemu/-/tree/master/contrib/plugins>`__ |
| folders. |
| * `po <https://gitlab.com/qemu-project/qemu/-/tree/master/po>`_: |
| Translation files. |
| * `python <https://gitlab.com/qemu-project/qemu/-/tree/master/python>`_: |
| Python part of our build/test system. |
| * `qapi <https://gitlab.com/qemu-project/qemu/-/tree/master/qapi>`_: |
| `QAPI <qapi>` implementation. |
| * `qobject <https://gitlab.com/qemu-project/qemu/-/tree/master/qobject>`_: |
| QEMU Object implementation. |
| * `qga <https://gitlab.com/qemu-project/qemu/-/tree/master/qga>`_: |
| QEMU `Guest agent <qemu-ga>` implementation. |
| * `qom <https://gitlab.com/qemu-project/qemu/-/tree/master/qom>`_: |
| QEMU :ref:`Object model <qom>` implementation, with monitor associated commands. |
| * `replay <https://gitlab.com/qemu-project/qemu/-/tree/master/replay>`_: |
| QEMU :ref:`Record/replay <replay>` implementation. |
| * `roms <https://gitlab.com/qemu-project/qemu/-/tree/master/roms>`_: |
| Contains source code for various firmware and ROMs, which can be compiled if |
| custom or updated versions are needed. |
| * `rust <https://gitlab.com/qemu-project/qemu/-/tree/master/rust>`_: |
| Rust integration in QEMU. It contains the new interfaces defined and |
| associated devices using it. |
| * `scripts <https://gitlab.com/qemu-project/qemu/-/tree/master/scripts>`_: |
| Collection of scripts used in build and test systems, and various |
| tools for QEMU codebase and execution traces. |
| * `scsi <https://gitlab.com/qemu-project/qemu/-/tree/master/scsi>`_: |
| Code related to SCSI support, used by SCSI devices. |
| * `semihosting <https://gitlab.com/qemu-project/qemu/-/tree/master/semihosting>`_: |
| QEMU `Semihosting <Semihosting>` implementation. |
| * `stats <https://gitlab.com/qemu-project/qemu/-/tree/master/stats>`_: |
| `Monitor <QEMU monitor>` stats commands implementation. |
| * `storage-daemon <https://gitlab.com/qemu-project/qemu/-/tree/master/storage-daemon>`_: |
| QEMU `Storage daemon <storage-daemon>` implementation. |
| * `stubs <https://gitlab.com/qemu-project/qemu/-/tree/master/stubs>`_: |
| Various stubs (empty functions) used to compile QEMU with specific |
| configurations. |
| * `subprojects <https://gitlab.com/qemu-project/qemu/-/tree/master/subprojects>`_: |
| QEMU submodules used by QEMU build system. |
| * `system <https://gitlab.com/qemu-project/qemu/-/tree/master/system>`_: |
| QEMU `system mode <System emulation>` implementation (cpu, mmu, boot support). |
| * `target <https://gitlab.com/qemu-project/qemu/-/tree/master/target>`_: |
| Contains code for all target architectures supported (one subfolder |
| per arch). For every architecture, you can find accelerator specific |
| implementations. |
| * `tcg <https://gitlab.com/qemu-project/qemu/-/tree/master/tcg>`_: |
| :ref:`TCG <tcg>` related code. |
| Contains one subfolder per host supported architecture. |
| * `tests <https://gitlab.com/qemu-project/qemu/-/tree/master/tests>`_: |
| QEMU `test <testing>` suite |
| |
| - `data <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/data>`_: |
| Data for various tests. |
| - `decode <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/decode>`_: |
| Testsuite for :ref:`decodetree <decodetree>` implementation. |
| - `docker <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/docker>`_: |
| Code and scripts to create `containers <container-ref>` used in `CI <ci>`. |
| - `fp <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/fp>`_: |
| QEMU testsuite for soft float implementation. |
| - `functional <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/functional>`_: |
| `Functional tests <checkfunctional-ref>` (full VM boot). |
| - `lcitool <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/lcitool>`_: |
| Generate dockerfiles for CI containers. |
| - `migration <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/migration>`_: |
| Test scripts and data for :ref:`Migration framework <migration>`. |
| - `multiboot <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/multiboot>`_: |
| Test multiboot functionality for x86_64/i386. |
| - `qapi-schema <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/qapi-schema>`_: |
| Test scripts and data for `QAPI <qapi-tests>`. |
| - `qemu-iotests <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/qemu-iotests>`_: |
| `Disk image and block tests <qemu-iotests>`. |
| - `qtest <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/qtest>`_: |
| `Device emulation testing <qtest>`. |
| - `tcg <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/tcg>`__: |
| `TCG related tests <checktcg-ref>`. Contains code per architecture |
| (subfolder) and multiarch tests as well. |
| - `tsan <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/tsan>`_: |
| `Suppressions <tsan-suppressions>` for thread sanitizer. |
| - `uefi-test-tools <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/uefi-test-tools>`_: |
| Test tool for UEFI support. |
| - `unit <https://gitlab.com/qemu-project/qemu/-/tree/master/tests/unit>`_: |
| QEMU `Unit tests <unit-tests>`. |
| * `trace <https://gitlab.com/qemu-project/qemu/-/tree/master/trace>`_: |
| :ref:`Tracing framework <tracing>`. Used to print information associated to various |
| events during execution. |
| * `ui <https://gitlab.com/qemu-project/qemu/-/tree/master/ui>`_: |
| QEMU User interfaces. |
| * `util <https://gitlab.com/qemu-project/qemu/-/tree/master/util>`_: |
| Utility code used by other parts of QEMU. |
