Go to file
Mikulas Patocka 2529497cb6 linux-user/hppa: clear the PSW 'N' bit when delivering signals
qemu-hppa may crash when delivering a signal. It can be demonstrated with
this program. Compile the program with "hppa-linux-gnu-gcc -O2 signal.c"
and run it with "qemu-hppa -one-insn-per-tb a.out". It reports that the
address of the flag is 0xb4 and it crashes when attempting to touch it.

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <signal.h>

sig_atomic_t flag;

void sig(int n)
{
	printf("&flag: %p\n", &flag);
	flag = 1;
}

int main(void)
{
	struct sigaction sa;
	struct itimerval it;

	sa.sa_handler = sig;
	sigemptyset(&sa.sa_mask);
	sa.sa_flags = SA_RESTART;
	if (sigaction(SIGALRM, &sa, NULL)) perror("sigaction"), exit(1);

	it.it_interval.tv_sec = 0;
	it.it_interval.tv_usec = 100;
	it.it_value.tv_sec = it.it_interval.tv_sec;
	it.it_value.tv_usec = it.it_interval.tv_usec;

	if (setitimer(ITIMER_REAL, &it, NULL)) perror("setitimer"), exit(1);

	while (1) {
	}
}

The reason for the crash is that the signal handling routine doesn't clear
the 'N' flag in the PSW. If the signal interrupts a thread when the 'N'
flag is set, the flag remains set at the beginning of the signal handler
and the first instruction of the signal handler is skipped.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Helge Deller <deller@gmx.de>
Cc: qemu-stable@nongnu.org
Signed-off-by: Helge Deller <deller@gmx.de>
2023-09-19 21:12:18 +02:00
.github/workflows github: fix config mistake preventing repo lockdown commenting 2022-04-26 16:12:26 +01:00
.gitlab/issue_templates .gitlab/issue_templates: Move suggestions into comments 2022-12-15 15:19:24 +01:00
.gitlab-ci.d .gitlab-ci.d/cirrus.yml: Update FreeBSD to v13.2 2023-08-30 14:57:50 +01:00
accel arm/kvm: Enable support for KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE 2023-09-08 16:41:36 +01:00
audio audio: spelling fixes 2023-09-08 13:08:52 +03:00
authz error: Drop superfluous #include "qapi/qmp/qerror.h" 2023-02-23 13:56:14 +01:00
backends misc/other: spelling fixes 2023-09-08 13:08:52 +03:00
block Block layer patches 2023-09-11 09:11:22 -04:00
bsd-user trace-events: Fix the name of the tracing.rst file 2023-09-08 13:08:51 +03:00
chardev misc/other: spelling fixes 2023-09-08 13:08:52 +03:00
common-user common-user/host/ppc: Implement safe-syscall.inc.S 2023-01-23 14:39:48 -10:00
configs target/loongarch: Add GDB support for loongarch32 mode 2023-08-24 11:17:56 +08:00
contrib * only build util/async-teardown.c when system build is requested 2023-09-07 10:29:06 -04:00
crypto crypto: Add SM4 constant parameter CK 2023-09-11 11:45:55 +10:00
disas riscv/disas: Fix disas output of upper immediates 2023-07-19 14:30:04 +10:00
docs vfio queue: 2023-09-11 09:13:08 -04:00
dump dump: kdump-zlib data pages not dumped with pvtime/aarch64 2023-08-07 15:46:59 +04:00
ebpf trace-events: Fix the name of the tracing.rst file 2023-09-08 13:08:51 +03:00
fpu fpu: Add float64_to_int{32,64}_modulo 2023-07-01 08:26:54 +02:00
fsdev 9pfs: deprecate 'proxy' backend 2023-07-06 11:42:08 +02:00
gdb-xml target/loongarch: Split fcc register to fcc0-7 in gdbstub 2023-08-24 11:17:59 +08:00
gdbstub configure, meson: remove target OS symbols from config-host.mak 2023-09-07 13:32:37 +02:00
host/include other architectures: spelling fixes 2023-07-25 17:14:07 +03:00
hw target/hppa: Report and clear BTLBs via fw_cfg at startup 2023-09-15 17:34:38 +02:00
include vfio queue: 2023-09-11 09:13:08 -04:00
io io: follow coroutine AioContext in qio_channel_yield() 2023-09-07 20:32:11 -05:00
libdecnumber libdecnumber/dpd/decimal64: Fix compiler warning from Clang 15 2022-11-11 09:13:52 +01:00
linux-headers linux-headers: update to v6.5-rc1 2023-07-10 09:52:52 +02:00
linux-user linux-user/hppa: clear the PSW 'N' bit when delivering signals 2023-09-19 21:12:18 +02:00
migration migration: Add .save_prepare() handler to struct SaveVMHandlers 2023-09-11 08:34:06 +02:00
monitor hw/char: Have FEWatchFunc handlers return G_SOURCE_CONTINUE/REMOVE 2023-08-31 19:47:43 +02:00
nbd trivial patches for 2023-09-08 2023-09-08 10:06:25 -04:00
net misc/other: spelling fixes 2023-09-08 13:08:52 +03:00
pc-bios target/hppa: Update to SeaBIOS-hppa version 9 2023-09-13 11:34:25 +02:00
plugins configure, meson: move --enable-plugins to meson 2023-09-07 13:32:37 +02:00
po po: add ukrainian translation 2022-07-05 10:15:49 +02:00
python Revert "mkvenv: work around broken pip installations on Debian 10" 2023-09-07 13:32:37 +02:00
qapi ui/vc: do not parse VC-specific options in Spice and GTK 2023-09-04 14:57:37 +04:00
qga qga/: spelling fixes 2023-09-08 13:08:52 +03:00
qobject docs/interop: Convert qmp-spec.txt to rST 2023-05-22 10:21:01 +02:00
qom meson: Replace softmmu_ss -> system_ss 2023-06-20 10:01:30 +02:00
replay meson: Replace softmmu_ss -> system_ss 2023-06-20 10:01:30 +02:00
roms target/hppa: Update to SeaBIOS-hppa version 9 2023-09-13 11:34:25 +02:00
scripts scripts/: spelling fixes 2023-09-08 13:08:52 +03:00
scsi io: follow coroutine AioContext in qio_channel_yield() 2023-09-07 20:32:11 -05:00
semihosting accel/tcg: spelling fixes 2023-08-31 19:47:43 +02:00
softmmu sysemu: Add prepare callback to struct VMChangeStateEntry 2023-09-11 08:34:05 +02:00
stats meson: Replace softmmu_ss -> system_ss 2023-06-20 10:01:30 +02:00
storage-daemon configure, meson: remove target OS symbols from config-host.mak 2023-09-07 13:32:37 +02:00
stubs stubs/colo.c: spelling 2023-08-07 13:52:59 +03:00
subprojects * only build util/async-teardown.c when system build is requested 2023-09-07 10:29:06 -04:00
target target/hppa: Wire up diag instruction to support BTLB 2023-09-19 21:12:18 +02:00
tcg * only build util/async-teardown.c when system build is requested 2023-09-07 10:29:06 -04:00
tests Block layer patches 2023-09-11 09:11:22 -04:00
tools ebpf: fix compatibility with libbpf 1.0+ 2023-03-10 17:26:47 +08:00
trace meson: Replace softmmu_ss -> system_ss 2023-06-20 10:01:30 +02:00
ui UI patch queue 2023-09-06 11:16:01 -04:00
util util/iov: Avoid dynamic stack allocation 2023-09-07 20:32:11 -05:00
.dir-locals.el Add .dir-locals.el file to configure emacs coding style 2015-10-08 19:46:01 +03:00
.editorconfig .editorconfig: update the automatic mode setting for Emacs 2021-03-10 15:34:11 +00:00
.exrc qemu: add .exrc 2012-09-07 09:02:44 +03:00
.gdbinit .gdbinit: load QEMU sub-commands when gdb starts 2017-06-07 14:38:45 +01:00
.git-blame-ignore-revs metadata: add .git-blame-ignore-revs 2023-04-04 15:56:44 +01:00
.gitattributes gitattributes: Cover Objective-C source files 2022-03-29 00:15:14 +02:00
.gitignore configure: rename --enable-pypi to --enable-download, control subprojects too 2023-06-06 16:30:01 +02:00
.gitlab-ci.yml docs: Document GitLab custom CI/CD variables 2021-07-29 07:56:01 +02:00
.gitmodules meson: subprojects: replace berkeley-{soft,test}float-3 with wraps 2023-06-06 16:30:01 +02:00
.gitpublish Add a git-publish configuration file 2018-03-05 09:03:17 +00:00
.mailmap MAINTAINERS: Update Roman Bolshakov email address 2023-06-28 13:55:09 +02:00
.patchew.yml scripts/checkpatch: roll diff tweaking into checkpatch itself 2021-06-25 10:08:33 +01:00
.readthedocs.yml readthedocs: build with Python 3.6 2020-10-05 16:30:45 +01:00
.travis.yml travis.yml: Add missing 'flex', 'bison' packages to 'GCC (user)' job 2023-04-20 11:24:50 +02:00
block.c Block layer patches 2023-09-11 09:11:22 -04:00
blockdev-nbd.c qapi block: Elide redundant has_FOO in generated C 2022-12-14 20:03:25 +01:00
blockdev.c cutils: Adjust signature of parse_uint[_full] 2023-06-02 12:27:19 -05:00
blockjob.c blockjob: Fix AioContext locking in block_job_add_bdrv() 2023-06-28 08:46:21 +02:00
configure Python: Drop support for Python 3.7 2023-09-07 13:32:37 +02:00
COPYING
COPYING.LIB COPYING.LIB: Synchronize the LGPL 2.1 with the version from gnu.org 2019-01-30 11:01:22 +01:00
cpu.c trivial: Simplify the spots that use TARGET_BIG_ENDIAN as a numeric value 2023-09-08 13:08:52 +03:00
cpus-common.c cpu: expose qemu_cpu_list_lock for lock-guard use 2023-05-11 09:53:41 +01:00
event-loop-base.c util/event-loop-base: Introduce options to set the thread pool size 2022-05-09 10:43:23 +01:00
gitdm.config contrib/gitdm: add group map for AMD 2023-03-22 15:08:26 +00:00
hmp-commands-info.hx accel/tcg: remove CONFIG_PROFILER 2023-06-26 17:33:00 +02:00
hmp-commands.hx build: move COLO under CONFIG_REPLICATION 2023-05-10 18:48:11 +02:00
iothread.c iothread: Set the GSource "name" field 2023-09-07 14:01:25 -04:00
job-qmp.c qapi job: Elide redundant has_FOO in generated C 2022-12-14 20:04:47 +01:00
job.c block: remove bdrv_try_set_aio_context and replace it with bdrv_try_change_aio_context 2022-10-27 20:14:11 +02:00
Kconfig meson: Introduce target-specific Kconfig 2021-07-09 18:21:34 +02:00
Kconfig.host vfio-user: build library 2022-06-15 16:42:33 +01:00
LICENSE tcg/LICENSE: Remove out of date claim about TCG subdirectory licensing 2019-11-11 15:11:21 +01:00
MAINTAINERS target-arm queue: 2023-09-11 09:10:37 -04:00
Makefile configure, meson: remove target OS symbols from config-host.mak 2023-09-07 13:32:37 +02:00
memory_ldst.c.inc exec/memory_ldst: Use correct type sizes 2021-05-26 08:35:51 -07:00
meson_options.txt * only build util/async-teardown.c when system build is requested 2023-09-07 10:29:06 -04:00
meson.build hw/ufs: Initial commit for emulated Universal-Flash-Storage 2023-09-07 14:01:29 -04:00
module-common.c all: Clean up includes 2016-02-04 17:41:30 +00:00
os-posix.c os-posix.c: remove unneeded #includes 2023-09-01 23:46:20 +02:00
os-win32.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
page-vary-common.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
page-vary.c include: move target page bits declaration to page-vary.h 2022-04-06 14:31:43 +02:00
pythondeps.toml Revert "tests: Use separate virtual environment for avocado" 2023-08-28 09:55:48 +02:00
qemu-bridge-helper.c qemu-bridge-helper: relocate path to default ACL 2020-09-30 19:11:36 +02:00
qemu-edid.c qemu-edid: Restrict input parameter -d to avoid division by zero 2022-10-12 13:38:15 +02:00
qemu-img-cmds.hx qemu-img: Unify [-b [-F]] documentation 2022-02-01 13:49:15 +01:00
qemu-img.c qemu-img: omit errno value in error message 2023-09-08 17:03:09 +02:00
qemu-io-cmds.c qemu-iotests: test zone append operation 2023-05-15 08:18:10 -04:00
qemu-io.c include: move qemu_*_exec_dir() to cutils 2022-05-28 11:42:56 +02:00
qemu-keymap.c qemu-keymap: properly check return from xkb_keymap_mod_get_index 2023-07-03 12:51:21 +01:00
qemu-nbd.c qemu-nbd: Restore "qemu-nbd -v --fork" output 2023-09-08 07:20:58 -05:00
qemu-options.hx target-arm queue: 2023-09-11 09:10:37 -04:00
qemu.nsi nsis installer: Fix mouse-over descriptions for emulators 2022-03-18 10:55:15 +00:00
qemu.sasl sasl: remove comment about obsolete kerberos versions 2021-06-14 13:28:50 +01:00
README.rst README.rst: fix link formatting 2022-08-04 13:44:21 +02:00
replication.c replication: move include out of root directory 2021-05-26 14:49:46 +02:00
trace-events trace-events: remove the remaining vcpu trace events 2023-06-01 11:05:05 -04:00
VERSION Open 8.2 development tree 2023-08-22 07:14:07 -07:00
version.rc configure: remove CONFIG_FILEVERSION and CONFIG_PRODUCTVERSION 2021-01-02 21:03:37 +01:00

===========
QEMU README
===========

QEMU is a generic and open source machine & userspace emulator and
virtualizer.

QEMU is capable of emulating a complete machine in software without any
need for hardware virtualization support. By using dynamic translation,
it achieves very good performance. QEMU can also integrate with the Xen
and KVM hypervisors to provide emulated hardware while allowing the
hypervisor to manage the CPU. With hypervisor support, QEMU can achieve
near native performance for CPUs. When QEMU emulates CPUs directly it is
capable of running operating systems made for one machine (e.g. an ARMv7
board) on a different machine (e.g. an x86_64 PC board).

QEMU is also capable of providing userspace API virtualization for Linux
and BSD kernel interfaces. This allows binaries compiled against one
architecture ABI (e.g. the Linux PPC64 ABI) to be run on a host using a
different architecture ABI (e.g. the Linux x86_64 ABI). This does not
involve any hardware emulation, simply CPU and syscall emulation.

QEMU aims to fit into a variety of use cases. It can be invoked directly
by users wishing to have full control over its behaviour and settings.
It also aims to facilitate integration into higher level management
layers, by providing a stable command line interface and monitor API.
It is commonly invoked indirectly via the libvirt library when using
open source applications such as oVirt, OpenStack and virt-manager.

QEMU as a whole is released under the GNU General Public License,
version 2. For full licensing details, consult the LICENSE file.


Documentation
=============

Documentation can be found hosted online at
`<https://www.qemu.org/documentation/>`_. The documentation for the
current development version that is available at
`<https://www.qemu.org/docs/master/>`_ is generated from the ``docs/``
folder in the source tree, and is built by `Sphinx
<https://www.sphinx-doc.org/en/master/>`_.


Building
========

QEMU is multi-platform software intended to be buildable on all modern
Linux platforms, OS-X, Win32 (via the Mingw64 toolchain) and a variety
of other UNIX targets. The simple steps to build QEMU are:


.. code-block:: shell

  mkdir build
  cd build
  ../configure
  make

Additional information can also be found online via the QEMU website:

* `<https://wiki.qemu.org/Hosts/Linux>`_
* `<https://wiki.qemu.org/Hosts/Mac>`_
* `<https://wiki.qemu.org/Hosts/W32>`_


Submitting patches
==================

The QEMU source code is maintained under the GIT version control system.

.. code-block:: shell

   git clone https://gitlab.com/qemu-project/qemu.git

When submitting patches, one common approach is to use 'git
format-patch' and/or 'git send-email' to format & send the mail to the
qemu-devel@nongnu.org mailing list. All patches submitted must contain
a 'Signed-off-by' line from the author. Patches should follow the
guidelines set out in the `style section
<https://www.qemu.org/docs/master/devel/style.html>`_ of
the Developers Guide.

Additional information on submitting patches can be found online via
the QEMU website

* `<https://wiki.qemu.org/Contribute/SubmitAPatch>`_
* `<https://wiki.qemu.org/Contribute/TrivialPatches>`_

The QEMU website is also maintained under source control.

.. code-block:: shell

  git clone https://gitlab.com/qemu-project/qemu-web.git

* `<https://www.qemu.org/2017/02/04/the-new-qemu-website-is-up/>`_

A 'git-publish' utility was created to make above process less
cumbersome, and is highly recommended for making regular contributions,
or even just for sending consecutive patch series revisions. It also
requires a working 'git send-email' setup, and by default doesn't
automate everything, so you may want to go through the above steps
manually for once.

For installation instructions, please go to

*  `<https://github.com/stefanha/git-publish>`_

The workflow with 'git-publish' is:

.. code-block:: shell

  $ git checkout master -b my-feature
  $ # work on new commits, add your 'Signed-off-by' lines to each
  $ git publish

Your patch series will be sent and tagged as my-feature-v1 if you need to refer
back to it in the future.

Sending v2:

.. code-block:: shell

  $ git checkout my-feature # same topic branch
  $ # making changes to the commits (using 'git rebase', for example)
  $ git publish

Your patch series will be sent with 'v2' tag in the subject and the git tip
will be tagged as my-feature-v2.

Bug reporting
=============

The QEMU project uses GitLab issues to track bugs. Bugs
found when running code built from QEMU git or upstream released sources
should be reported via:

* `<https://gitlab.com/qemu-project/qemu/-/issues>`_

If using QEMU via an operating system vendor pre-built binary package, it
is preferable to report bugs to the vendor's own bug tracker first. If
the bug is also known to affect latest upstream code, it can also be
reported via GitLab.

For additional information on bug reporting consult:

* `<https://wiki.qemu.org/Contribute/ReportABug>`_


ChangeLog
=========

For version history and release notes, please visit
`<https://wiki.qemu.org/ChangeLog/>`_ or look at the git history for
more detailed information.


Contact
=======

The QEMU community can be contacted in a number of ways, with the two
main methods being email and IRC

* `<mailto:qemu-devel@nongnu.org>`_
* `<https://lists.nongnu.org/mailman/listinfo/qemu-devel>`_
* #qemu on irc.oftc.net

Information on additional methods of contacting the community can be
found online via the QEMU website:

* `<https://wiki.qemu.org/Contribute/StartHere>`_