xref: /openbmc/qemu/README.rst (revision 83340193)
1===========
2QEMU README
3===========
4
5QEMU is a generic and open source machine & userspace emulator and
6virtualizer.
7
8QEMU is capable of emulating a complete machine in software without any
9need for hardware virtualization support. By using dynamic translation,
10it achieves very good performance. QEMU can also integrate with the Xen
11and KVM hypervisors to provide emulated hardware while allowing the
12hypervisor to manage the CPU. With hypervisor support, QEMU can achieve
13near native performance for CPUs. When QEMU emulates CPUs directly it is
14capable of running operating systems made for one machine (e.g. an ARMv7
15board) on a different machine (e.g. an x86_64 PC board).
16
17QEMU is also capable of providing userspace API virtualization for Linux
18and BSD kernel interfaces. This allows binaries compiled against one
19architecture ABI (e.g. the Linux PPC64 ABI) to be run on a host using a
20different architecture ABI (e.g. the Linux x86_64 ABI). This does not
21involve any hardware emulation, simply CPU and syscall emulation.
22
23QEMU aims to fit into a variety of use cases. It can be invoked directly
24by users wishing to have full control over its behaviour and settings.
25It also aims to facilitate integration into higher level management
26layers, by providing a stable command line interface and monitor API.
27It is commonly invoked indirectly via the libvirt library when using
28open source applications such as oVirt, OpenStack and virt-manager.
29
30QEMU as a whole is released under the GNU General Public License,
31version 2. For full licensing details, consult the LICENSE file.
32
33
34Documentation
35=============
36
37Documentation can be found hosted online at
38`<https://www.qemu.org/documentation/>`_. The documentation for the
39current development version that is available at
40`<https://www.qemu.org/docs/master/>`_ is generated from the ``docs/``
41folder in the source tree, and is built by `Sphinx
42<https://www.sphinx-doc.org/en/master/>`_.
43
44
45Building
46========
47
48QEMU is multi-platform software intended to be buildable on all modern
49Linux platforms, OS-X, Win32 (via the Mingw64 toolchain) and a variety
50of other UNIX targets. The simple steps to build QEMU are:
51
52
53.. code-block:: shell
54
55  mkdir build
56  cd build
57  ../configure
58  make
59
60Additional information can also be found online via the QEMU website:
61
62* `<https://wiki.qemu.org/Hosts/Linux>`_
63* `<https://wiki.qemu.org/Hosts/Mac>`_
64* `<https://wiki.qemu.org/Hosts/W32>`_
65
66
67Submitting patches
68==================
69
70The QEMU source code is maintained under the GIT version control system.
71
72.. code-block:: shell
73
74   git clone https://gitlab.com/qemu-project/qemu.git
75
76When submitting patches, one common approach is to use 'git
77format-patch' and/or 'git send-email' to format & send the mail to the
78qemu-devel@nongnu.org mailing list. All patches submitted must contain
79a 'Signed-off-by' line from the author. Patches should follow the
80guidelines set out in the `style section
81<https://www.qemu.org/docs/master/devel/style.html>`_ of
82the Developers Guide.
83
84Additional information on submitting patches can be found online via
85the QEMU website:
86
87* `<https://wiki.qemu.org/Contribute/SubmitAPatch>`_
88* `<https://wiki.qemu.org/Contribute/TrivialPatches>`_
89
90The QEMU website is also maintained under source control.
91
92.. code-block:: shell
93
94  git clone https://gitlab.com/qemu-project/qemu-web.git
95
96* `<https://www.qemu.org/2017/02/04/the-new-qemu-website-is-up/>`_
97
98A 'git-publish' utility was created to make above process less
99cumbersome, and is highly recommended for making regular contributions,
100or even just for sending consecutive patch series revisions. It also
101requires a working 'git send-email' setup, and by default doesn't
102automate everything, so you may want to go through the above steps
103manually for once.
104
105For installation instructions, please go to:
106
107*  `<https://github.com/stefanha/git-publish>`_
108
109The workflow with 'git-publish' is:
110
111.. code-block:: shell
112
113  $ git checkout master -b my-feature
114  $ # work on new commits, add your 'Signed-off-by' lines to each
115  $ git publish
116
117Your patch series will be sent and tagged as my-feature-v1 if you need to refer
118back to it in the future.
119
120Sending v2:
121
122.. code-block:: shell
123
124  $ git checkout my-feature # same topic branch
125  $ # making changes to the commits (using 'git rebase', for example)
126  $ git publish
127
128Your patch series will be sent with 'v2' tag in the subject and the git tip
129will be tagged as my-feature-v2.
130
131Bug reporting
132=============
133
134The QEMU project uses GitLab issues to track bugs. Bugs
135found when running code built from QEMU git or upstream released sources
136should be reported via:
137
138* `<https://gitlab.com/qemu-project/qemu/-/issues>`_
139
140If using QEMU via an operating system vendor pre-built binary package, it
141is preferable to report bugs to the vendor's own bug tracker first. If
142the bug is also known to affect latest upstream code, it can also be
143reported via GitLab.
144
145For additional information on bug reporting consult:
146
147* `<https://wiki.qemu.org/Contribute/ReportABug>`_
148
149
150ChangeLog
151=========
152
153For version history and release notes, please visit
154`<https://wiki.qemu.org/ChangeLog/>`_ or look at the git history for
155more detailed information.
156
157
158Contact
159=======
160
161The QEMU community can be contacted in a number of ways, with the two
162main methods being email and IRC:
163
164* `<mailto:qemu-devel@nongnu.org>`_
165* `<https://lists.nongnu.org/mailman/listinfo/qemu-devel>`_
166* #qemu on irc.oftc.net
167
168Information on additional methods of contacting the community can be
169found online via the QEMU website:
170
171* `<https://wiki.qemu.org/Contribute/StartHere>`_
172