xref: /openbmc/qemu/README.rst (revision 6f03770d)
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
34Building
35========
36
37QEMU is multi-platform software intended to be buildable on all modern
38Linux platforms, OS-X, Win32 (via the Mingw64 toolchain) and a variety
39of other UNIX targets. The simple steps to build QEMU are:
40
41
42.. code-block:: shell
43
44  mkdir build
45  cd build
46  ../configure
47  make
48
49Additional information can also be found online via the QEMU website:
50
51* `<https://qemu.org/Hosts/Linux>`_
52* `<https://qemu.org/Hosts/Mac>`_
53* `<https://qemu.org/Hosts/W32>`_
54
55
56Submitting patches
57==================
58
59The QEMU source code is maintained under the GIT version control system.
60
61.. code-block:: shell
62
63   git clone https://gitlab.com/qemu-project/qemu.git
64
65When submitting patches, one common approach is to use 'git
66format-patch' and/or 'git send-email' to format & send the mail to the
67qemu-devel@nongnu.org mailing list. All patches submitted must contain
68a 'Signed-off-by' line from the author. Patches should follow the
69guidelines set out in the `style section
70<https://www.qemu.org/docs/master/devel/style.html>` of
71the Developers Guide.
72
73Additional information on submitting patches can be found online via
74the QEMU website
75
76* `<https://qemu.org/Contribute/SubmitAPatch>`_
77* `<https://qemu.org/Contribute/TrivialPatches>`_
78
79The QEMU website is also maintained under source control.
80
81.. code-block:: shell
82
83  git clone https://gitlab.com/qemu-project/qemu-web.git
84
85* `<https://www.qemu.org/2017/02/04/the-new-qemu-website-is-up/>`_
86
87A 'git-publish' utility was created to make above process less
88cumbersome, and is highly recommended for making regular contributions,
89or even just for sending consecutive patch series revisions. It also
90requires a working 'git send-email' setup, and by default doesn't
91automate everything, so you may want to go through the above steps
92manually for once.
93
94For installation instructions, please go to
95
96*  `<https://github.com/stefanha/git-publish>`_
97
98The workflow with 'git-publish' is:
99
100.. code-block:: shell
101
102  $ git checkout master -b my-feature
103  $ # work on new commits, add your 'Signed-off-by' lines to each
104  $ git publish
105
106Your patch series will be sent and tagged as my-feature-v1 if you need to refer
107back to it in the future.
108
109Sending v2:
110
111.. code-block:: shell
112
113  $ git checkout my-feature # same topic branch
114  $ # making changes to the commits (using 'git rebase', for example)
115  $ git publish
116
117Your patch series will be sent with 'v2' tag in the subject and the git tip
118will be tagged as my-feature-v2.
119
120Bug reporting
121=============
122
123The QEMU project uses Launchpad as its primary upstream bug tracker. Bugs
124found when running code built from QEMU git or upstream released sources
125should be reported via:
126
127* `<https://bugs.launchpad.net/qemu/>`_
128
129If using QEMU via an operating system vendor pre-built binary package, it
130is preferable to report bugs to the vendor's own bug tracker first. If
131the bug is also known to affect latest upstream code, it can also be
132reported via launchpad.
133
134For additional information on bug reporting consult:
135
136* `<https://qemu.org/Contribute/ReportABug>`_
137
138
139ChangeLog
140=========
141
142For version history and release notes, please visit
143`<https://wiki.qemu.org/ChangeLog/>`_ or look at the git history for
144more detailed information.
145
146
147Contact
148=======
149
150The QEMU community can be contacted in a number of ways, with the two
151main methods being email and IRC
152
153* `<mailto:qemu-devel@nongnu.org>`_
154* `<https://lists.nongnu.org/mailman/listinfo/qemu-devel>`_
155* #qemu on irc.oftc.net
156
157Information on additional methods of contacting the community can be
158found online via the QEMU website:
159
160* `<https://qemu.org/Contribute/StartHere>`_
161