QEMU With E2K User Support
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Peter Xu bc6a69dd4b qemu-error: introduce {error|warn}_report_once
There are many error_report()s that can be used in frequently called
functions, especially on IO paths.  That can be unideal in that
malicious guest can try to trigger the error tons of time which might
use up the log space on the host (e.g., libvirt can capture the stderr
of QEMU and put it persistently onto disk).  In VT-d emulation code, we
have trace_vtd_error() tracer.  AFAIU all those places can be replaced
by something like error_report() but trace points are mostly used to
avoid the DDOS attack that mentioned above.  However using trace points
mean that errors are not dumped if trace not enabled.

It's not a big deal in most modern server managements since we have
things like logrotate to maintain the logs and make sure the quota is
expected.  However it'll still be nice that we just provide another way
to restrict message generations.  In most cases, this kind of
error_report()s will only provide valid information on the first message
sent, and all the rest of similar messages will be mostly talking about
the same thing.  This patch introduces *_report_once() helpers to allow
a message to be dumped only once during one QEMU process's life cycle.
It will make sure: (1) it's on by deffault, so we can even get something
without turning the trace on and reproducing, and (2) it won't be
affected by DDOS attack.

To implement it, I stole the printk_once() macro from Linux.

CC: Eric Blake <eblake@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180815095328.32414-2-peterx@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Whitespace adjusted, comments improved]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2018-08-27 06:38:45 +02:00
accel KVM: cleanup unnecessary #ifdef KVM_CAP_... 2018-08-23 18:46:25 +02:00
audio audio: add audio timer trace points 2018-07-03 11:46:47 +02:00
backends hostmem-file: add the 'pmem' option 2018-08-10 13:29:39 +03:00
block Block layer patches: 2018-08-15 22:11:08 +01:00
bsd-user bsd-user: Use the IEC binary prefix definitions 2018-07-02 15:41:18 +02:00
capstone@22ead3e0bf disas: Add capstone as submodule 2017-10-26 11:56:20 +02:00
chardev qemu-char: check errno together with ret < 0 2018-07-06 18:39:19 +02:00
contrib vhost-blk: turn on pre-defined RO feature bit 2018-06-01 19:20:38 +03:00
crypto crypto: Implement TLS Pre-Shared Keys (PSK). 2018-07-03 13:04:38 +01:00
default-configs hw/misc/tz-msc: Model TrustZone Master Security Controller 2018-08-24 13:17:43 +01:00
disas fix "Missing break in switch" coverity reports 2018-08-23 13:32:50 +02:00
docs QObject patches for 2018-08-24 2018-08-25 10:11:54 +01:00
dtc@e54388015a Update dtc to fix compilation problem on Mac OS 10.6 2018-01-10 12:53:00 +11:00
fpu softfloat: Add scaling float-to-int routines 2018-08-24 13:17:30 +01:00
fsdev fsdev: fix compilation with VIRTIO but not VIRTIO_9P 2018-08-22 12:21:13 +02:00
gdb-xml s390x/gdb: add gs registers 2017-07-14 12:29:49 +02:00
hw VFIO fixes 2018-08-23 2018-08-25 10:59:06 +01:00
include qemu-error: introduce {error|warn}_report_once 2018-08-27 06:38:45 +02:00
io Delete AF_UNIX socket after close 2018-06-28 13:36:59 +01:00
libdecnumber build: remove CONFIG_LIBDECNUMBER 2017-10-16 18:03:52 +02:00
linux-headers linux-headers: update 2018-08-20 14:18:49 +02:00
linux-user elf: Don't check FCR31_NAN2008 bit for nanoMIPS 2018-08-24 17:51:59 +02:00
migration VFIO fixes 2018-08-23 2018-08-25 10:59:06 +01:00
nbd nbd/server: fix nbd_co_send_block_status 2018-07-07 20:30:09 -05:00
net tap: fix memory leak on success to create a tap device 2018-07-20 08:30:49 +08:00
pc-bios * x86 TCG fixes for 64-bit call gates (Andrew) 2018-08-23 19:03:54 +01:00
po po: Don't include comments with location 2018-07-23 10:50:54 +01:00
qapi QObject patches for 2018-08-24 2018-08-25 10:11:54 +01:00
qga json: Clean up headers 2018-08-24 20:26:37 +02:00
qobject json: Update references to RFC 7159 to RFC 8259 2018-08-24 20:27:14 +02:00
qom qom/object: Add a new function object_initialize_child() 2018-07-17 13:12:49 +01:00
replay replay: save vmstate of the asynchronous events 2018-03-12 17:10:38 +01:00
roms pseries: Update SLOF firmware image 2018-08-21 14:28:45 +10:00
scripts qemu-guest-agent: freeze-hook to ignore dpkg files as well 2018-08-23 18:46:25 +02:00
scsi qemu-pr-helper: Fix build on CentOS 7 2018-08-23 13:32:50 +02:00
slirp slirp: Correct size check in m_inc() 2018-08-07 14:13:22 +01:00
stubs qsp: track BQL callers explicitly 2018-08-23 18:46:25 +02:00
target target/mips: Add definition of nanoMIPS I7200 CPU 2018-08-24 17:51:59 +02:00
tcg tcg/optimize: Do not skip default processing of dup_vec 2018-08-06 14:57:48 +01:00
tests json: Support %% in JSON strings when interpolating 2018-08-24 20:26:37 +02:00
trace tracing: Use double-dash spelling for trace option 2018-07-19 13:09:04 +01:00
ui ui/cocoa.m: prevent stuck command key when going into full screen mode 2018-07-24 11:41:48 +01:00
util json: Reject invalid UTF-8 sequences 2018-08-24 20:26:37 +02:00
.dir-locals.el Add .dir-locals.el file to configure emacs coding style 2015-10-08 19:46:01 +03:00
.editorconfig add editorconfig 2017-07-20 09:56:56 +02:00
.exrc
.gdbinit .gdbinit: load QEMU sub-commands when gdb starts 2017-06-07 14:38:45 +01:00
.gitignore .gitignore: add .gcov files 2018-07-05 15:59:41 +01:00
.gitmodules vgabios: remove submodule and build rules. 2018-07-02 17:20:54 +02:00
.gitpublish Add a git-publish configuration file 2018-03-05 09:03:17 +00:00
.mailmap MAINTAINERS: Update target/mips maintainer's email addresses 2018-08-16 19:18:45 +02:00
.shippable.yml shippable: Remove Debian 8 libfdt kludge 2018-05-11 14:33:40 +02:00
.travis.yml travis: add gcovr summary for GCOV build 2018-07-05 15:59:41 +01:00
arch_init.c arch_init: sort architectures 2018-06-01 19:20:38 +03:00
balloon.c balloon: Allow multiple inhibit users 2018-08-17 09:27:15 -06:00
block.c qjson: Have qobject_from_json() & friends reject empty and blank 2018-08-24 20:26:37 +02:00
blockdev-nbd.c qapi: new qmp command nbd-server-add-bitmap 2018-06-21 09:23:59 -05:00
blockdev.c block: Remove dead deprecation warning code 2018-08-15 12:50:39 +02:00
blockjob.c block: Really pause block jobs on drain 2018-06-18 15:03:25 +02:00
bootdevice.c fw_cfg: ignore suffixes in the bootdevice list dependent on machine class 2018-08-16 22:27:43 -03:00
bt-host.c all: Clean up includes 2016-02-04 17:41:30 +00:00
bt-vhci.c all: Clean up includes 2016-02-04 17:41:30 +00:00
Changelog Use HTTPS for qemu.org and other domains 2017-11-21 13:34:13 +00:00
CODING_STYLE CODING_STYLE: Define our preferred form for multiline comments 2018-06-15 15:23:34 +01:00
configure pull-seccomp-20180823 2018-08-25 13:08:57 +01:00
COPYING
COPYING.LIB
cpus-common.c qom: convert the CPU list to RCU 2018-08-23 18:46:25 +02:00
cpus.c cpus: allow cpu_get_ticks out of BQL 2018-08-23 18:46:25 +02:00
device_tree.c device_tree: Add qemu_fdt_node_unit_path 2018-06-29 15:11:01 +01:00
device-hotplug.c block: Remove deprecated -drive option addr 2018-08-15 12:50:39 +02:00
disas.c RISC-V Disassembler 2018-03-07 08:30:28 +13:00
dma-helpers.c block: explicitly acquire aiocontext in bottom halves that need it 2017-02-21 11:39:39 +00:00
dump.c fw_cfg: import & use linux/qemu_fw_cfg.h 2018-08-23 18:46:25 +02:00
exec.c pc: fixes 2018-08-21 10:23:53 +01:00
gdbstub.c gdbstub: Prevent fd leakage 2018-06-01 15:14:31 +02:00
HACKING HACKING: document preference for g_new instead of g_malloc 2018-05-20 08:32:09 +03:00
hmp-commands-info.hx hmp-commands-info: add sync-profile 2018-08-23 18:46:25 +02:00
hmp-commands.hx hmp-commands: add sync-profile 2018-08-23 18:46:25 +02:00
hmp.c migration/next for 20180822 2018-08-24 16:31:53 +01:00
hmp.h hmp-commands: add sync-profile 2018-08-23 18:46:25 +02:00
ioport.c trace: switch to modular code generation for sub-directories 2017-01-31 17:11:18 +00:00
iothread.c iothread: workaround glib bug which hangs qmp-test 2018-04-10 07:43:52 -05:00
job-qmp.c job: Add error message for failing jobs 2018-05-30 13:31:01 +02:00
job.c block: for jobs, do not clear user_paused until after the resume 2018-08-21 14:59:30 -04:00
LICENSE vfio: move hw/misc/vfio.c to hw/vfio/pci.c Move vfio.h into include/hw/vfio 2014-12-19 15:24:06 -07:00
MAINTAINERS qmp-cmd-test: Split off qmp-test 2018-08-24 20:25:48 +02:00
Makefile docs: add guidance on configuring CPU models for x86 2018-08-16 13:43:01 -03:00
Makefile.objs hw/watchdog/cmsdk_apb_watchdog: Implement CMSDK APB watchdog module 2018-08-20 11:24:33 +01:00
Makefile.target dump: add Windows dump format to dump-guest-memory 2018-06-29 13:02:48 +02:00
memory_ldst.inc.c exec: Fix MAP_RAM for cached access 2018-06-28 19:05:30 +02:00
memory_mapping.c Replace all occurances of __FUNCTION__ with __func__ 2018-01-22 09:46:18 +01:00
memory.c pc: fixes 2018-08-21 10:23:53 +01:00
module-common.c all: Clean up includes 2016-02-04 17:41:30 +00:00
monitor.c json: Clean up headers 2018-08-24 20:26:37 +02:00
numa.c memory, exec: switch file ram allocation functions to 'flags' parameters 2018-08-10 13:29:39 +03:00
os-posix.c qemu-options: Bail out on unsupported options instead of silently ignoring them 2018-05-09 00:13:39 +02:00
os-win32.c qemu-options: Bail out on unsupported options instead of silently ignoring them 2018-05-09 00:13:39 +02:00
qdev-monitor.c qom: introduce object_class_get_list_sorted 2018-03-12 15:21:10 +01:00
qdict-test-data.txt
qemu-bridge-helper.c all: Remove unnecessary glib.h includes 2016-06-07 18:19:24 +03:00
qemu-deprecated.texi qemu-doc: mark ppc/prep machine as deprecated 2018-08-21 14:28:45 +10:00
qemu-doc.texi x86 queue, 2018-08-16 2018-08-17 09:46:00 +01:00
qemu-ga.texi qemu-ga: Remove stray 'q' in documentation 2016-10-28 18:17:23 +03:00
qemu-img-cmds.hx qemu-img: Add -C option for convert with copy offloading 2018-07-30 15:35:37 +02:00
qemu-img.c qemu-img: fix regression copying secrets during convert 2018-08-15 12:50:39 +02:00
qemu-img.texi qemu-img: Add -C option for convert with copy offloading 2018-07-30 15:35:37 +02:00
qemu-io-cmds.c qemu-io: Let command functions return error code 2018-06-11 16:18:45 +02:00
qemu-io.c qemu-io: Exit with error when a command failed 2018-06-11 16:18:45 +02:00
qemu-keymap.c Drop superfluous includes of qapi-types.h and test-qapi-types.h 2018-02-09 05:05:11 +01:00
qemu-nbd.c block: Cancel job in bdrv_close_all() callers 2018-05-23 14:30:51 +02:00
qemu-nbd.texi nbd: Add qemu-nbd -D for human-readable description 2016-11-02 09:28:55 +01:00
qemu-option-trace.texi qemu-option-trace: -trace enable= is a pattern, not a file 2018-05-20 08:29:01 +03:00
qemu-options-wrapper.h qemu-img: remove references to GEN_DOCS 2018-05-20 08:35:54 +03:00
qemu-options.h Clean up ill-advised or unusual header guards 2016-07-12 16:20:46 +02:00
qemu-options.hx vl: add -enable-sync-profile 2018-08-23 18:46:25 +02:00
qemu-seccomp.c seccomp: set the seccomp filter to all threads 2018-08-23 16:45:44 +02:00
qemu-tech.texi cli qmp: Mark --preconfig, exit-preconfig experimental 2018-07-16 15:38:19 +02:00
qemu.nsi Use HTTPS for qemu.org and other domains 2017-11-21 13:34:13 +00:00
qemu.sasl Default to GSSAPI (Kerberos) instead of DIGEST-MD5 for SASL 2017-05-09 14:41:47 +01:00
qmp.c cli qmp: Mark --preconfig, exit-preconfig experimental 2018-07-16 15:38:19 +02:00
qtest.c qtest: Use cpu address space instead of system memory 2018-07-06 18:39:19 +02:00
README README: Fix typo 'git-publish' 2018-03-08 15:45:14 +00:00
replication.c replication: Introduce new APIs to do replication operation 2016-09-13 11:00:56 +01:00
replication.h block/replication: Remove protocol_name field 2018-03-26 12:16:00 +02:00
rules.mak tests/docker/Makefile.include: handle empty TARGET_LIST 2018-06-04 14:39:18 +08:00
thunk.c thunk: assert nb_fields is valid 2017-07-31 13:06:39 +03:00
tpm.c qapi: Move qapi-schema.json to qapi/, rename generated files 2018-03-02 13:45:57 -06:00
trace-events job: Add lifecycle QMP commands 2018-05-23 14:30:51 +02:00
VERSION Open 3.1 development tree 2018-08-14 17:10:49 +01:00
version.rc Use HTTPS for qemu.org and other domains 2017-11-21 13:34:13 +00:00
vl.c kvm: add call to qemu_add_opts() for -overcommit option 2018-08-23 18:46:25 +02:00
win_dump.c dump: add Windows live system dump 2018-06-29 13:02:50 +02:00
win_dump.h dump: add Windows live system dump 2018-06-29 13:02:50 +02:00

         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.


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:

  mkdir build
  cd build
  ../configure
  make

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

  https://qemu.org/Hosts/Linux
  https://qemu.org/Hosts/Mac
  https://qemu.org/Hosts/W32


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

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

   git clone git://git.qemu.org/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 HACKING and CODING_STYLE files.

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

  https://qemu.org/Contribute/SubmitAPatch
  https://qemu.org/Contribute/TrivialPatches

The QEMU website is also maintained under source control.

  git clone git://git.qemu.org/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:

  $ 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:

  $ 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 Launchpad as its primary upstream bug tracker. Bugs
found when running code built from QEMU git or upstream released sources
should be reported via:

  https://bugs.launchpad.net/qemu/

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 launchpad.

For additional information on bug reporting consult:

  https://qemu.org/Contribute/ReportABug


Contact
=======

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

 - 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://qemu.org/Contribute/StartHere

-- End