xref: /openbmc/qemu/README.rst (revision 284d697c)
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://git.qemu.org/git/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 CODING_STYLE.rst file.
70
71Additional information on submitting patches can be found online via
72the QEMU website
73
74* `<https://qemu.org/Contribute/SubmitAPatch>`_
75* `<https://qemu.org/Contribute/TrivialPatches>`_
76
77The QEMU website is also maintained under source control.
78
79.. code-block:: shell
80
81  git clone https://git.qemu.org/git/qemu-web.git
82
83* `<https://www.qemu.org/2017/02/04/the-new-qemu-website-is-up/>`_
84
85A 'git-publish' utility was created to make above process less
86cumbersome, and is highly recommended for making regular contributions,
87or even just for sending consecutive patch series revisions. It also
88requires a working 'git send-email' setup, and by default doesn't
89automate everything, so you may want to go through the above steps
90manually for once.
91
92For installation instructions, please go to
93
94*  `<https://github.com/stefanha/git-publish>`_
95
96The workflow with 'git-publish' is:
97
98.. code-block:: shell
99
100  $ git checkout master -b my-feature
101  $ # work on new commits, add your 'Signed-off-by' lines to each
102  $ git publish
103
104Your patch series will be sent and tagged as my-feature-v1 if you need to refer
105back to it in the future.
106
107Sending v2:
108
109.. code-block:: shell
110
111  $ git checkout my-feature # same topic branch
112  $ # making changes to the commits (using 'git rebase', for example)
113  $ git publish
114
115Your patch series will be sent with 'v2' tag in the subject and the git tip
116will be tagged as my-feature-v2.
117
118Bug reporting
119=============
120
121The QEMU project uses Launchpad as its primary upstream bug tracker. Bugs
122found when running code built from QEMU git or upstream released sources
123should be reported via:
124
125* `<https://bugs.launchpad.net/qemu/>`_
126
127If using QEMU via an operating system vendor pre-built binary package, it
128is preferable to report bugs to the vendor's own bug tracker first. If
129the bug is also known to affect latest upstream code, it can also be
130reported via launchpad.
131
132For additional information on bug reporting consult:
133
134* `<https://qemu.org/Contribute/ReportABug>`_
135
136
137ChangeLog
138=========
139
140For version history and release notes, please visit
141`<https://wiki.qemu.org/ChangeLog/>`_ or look at the git history for
142more detailed information.
143
144
145Contact
146=======
147
148The QEMU community can be contacted in a number of ways, with the two
149main methods being email and IRC
150
151* `<mailto:qemu-devel@nongnu.org>`_
152* `<https://lists.nongnu.org/mailman/listinfo/qemu-devel>`_
153* #qemu on irc.oftc.net
154
155Information on additional methods of contacting the community can be
156found online via the QEMU website:
157
158* `<https://qemu.org/Contribute/StartHere>`_
159