Go to file
Kevin Wolf 1cc8e54ada block: Avoid unnecessary aio_poll() in AIO_WAIT_WHILE()
Commit 91af091f92 added an additional aio_poll() to BDRV_POLL_WHILE()
in order to make sure that all pending BHs are executed on drain. This
was the wrong place to make the fix, as it is useless overhead for all
other users of the macro and unnecessarily complicates the mechanism.

This patch effectively reverts said commit (the context has changed a
bit and the code has moved to AIO_WAIT_WHILE()) and instead polls in the
loop condition for drain.

The effect is probably hard to measure in any real-world use case
because actual I/O will dominate, but if I run only the initialisation
part of 'qemu-img convert' where it calls bdrv_block_status() for the
whole image to find out how much data there is copy, this phase actually
needs only roughly half the time after this patch.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2018-06-18 15:03:25 +02:00
accel exec.c: Handle IOMMUs in address_space_translate_for_iotlb() 2018-06-15 15:23:34 +01:00
audio audio/sdl: build as module 2018-03-12 11:18:27 +01:00
backends vhost-user: introduce shared vhost-user state 2018-05-24 21:14:11 +03:00
block block: Avoid unnecessary aio_poll() in AIO_WAIT_WHILE() 2018-06-18 15:03:25 +02:00
bsd-user target: Do not include "exec/exec-all.h" if it is not necessary 2018-06-01 14:15:10 +02:00
capstone@22ead3e0bf disas: Add capstone as submodule 2017-10-26 11:56:20 +02:00
chardev chardev: Restore CR,LF on stdio 2018-06-08 11:45:16 +01:00
contrib vhost-blk: turn on pre-defined RO feature bit 2018-06-01 19:20:38 +03:00
crypto crypto: use local path for local headers 2018-06-01 19:20:37 +03:00
default-configs misc: add pca9552 LED blinker model 2018-06-08 13:15:32 +01:00
disas RISC-V: Fix missing break statement in disassembler 2018-05-06 10:39:38 +12:00
docs bswap: Add new stn_*_p() and ldn_*_p() memory access functions 2018-06-15 15:23:34 +01:00
dtc@e54388015a Update dtc to fix compilation problem on Mac OS 10.6 2018-01-10 12:53:00 +11:00
fpu fpu/softfloat: Define floatN_silence_nan in terms of parts_silence_nan 2018-05-17 15:27:15 -07:00
fsdev use g_path_get_basename instead of basename 2018-03-06 14:01:29 +01:00
gdb-xml s390x/gdb: add gs registers 2017-07-14 12:29:49 +02:00
hw Block layer patches: 2018-06-15 16:30:27 +01:00
include block: Avoid unnecessary aio_poll() in AIO_WAIT_WHILE() 2018-06-18 15:03:25 +02:00
io Remove unnecessary variables for function return value 2018-05-20 08:48:13 +03:00
libdecnumber build: remove CONFIG_LIBDECNUMBER 2017-10-16 18:03:52 +02:00
linux-headers Update Linux headers to 4.17-rc6 2018-06-01 15:14:31 +02:00
linux-user linux-user/sparc64: Add inotify_rm_watch and tee syscalls 2018-06-11 14:47:45 +02:00
migration migration: calculate expected_downtime with ram_bytes_remaining() 2018-06-15 14:40:56 +01:00
nbd nbd/client: Fix error messages during NBD_INFO_BLOCK_SIZE 2018-05-04 08:23:37 -05:00
net vhost-user: delete net client if necessary 2018-06-15 10:39:53 +08:00
pc-bios pc-bios/s390-ccw: struct tpi_info must be declared as aligned(4) 2018-05-14 17:10:02 +02:00
po po: add missing translations in de, fr, it, zh 2016-12-14 18:47:19 +00:00
qapi Migration pull 2018-06-15 2018-06-15 18:13:35 +01:00
qga qga: use local path for local headers 2018-06-01 19:20:38 +03:00
qobject block: Fix -blockdev / blockdev-add for empty objects and arrays 2018-06-15 14:49:44 +02:00
qom Purge uses of banned g_assert_FOO() 2018-06-13 13:47:35 +02:00
replay replay: save vmstate of the asynchronous events 2018-03-12 17:10:38 +01:00
roms roms/u-boot-sam460ex: Change to qemu git mirror and update 2018-04-10 10:05:38 +10:00
scripts Miscellaneous patches for 2018-06-13 2018-06-14 11:35:22 +01:00
scsi qemu-pr-helper: Write pidfile more often 2018-04-09 16:36:40 +02:00
slirp slirp: reformat m_inc routine 2018-06-08 09:08:30 +03:00
stubs pc-dimm: factor out MemoryDevice interface 2018-05-07 10:00:02 -03:00
target xilinx-next-2018-06-15.for-upstream 2018-06-15 17:28:37 +01:00
tcg tcg-next queue 2018-06-04 11:28:31 +01:00
tests tests/test-bdrv-drain: bdrv_drain_all() works in coroutines now 2018-06-18 15:03:25 +02:00
trace trace: use local path for local headers 2018-06-01 19:20:37 +03:00
ui sdl2: restore window dimensions by resize 2018-06-14 09:55:09 +02:00
util block: Add block-specific QDict header 2018-06-15 14:49:44 +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 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
.gitignore block: Ignore generated job QAPI files 2018-06-13 10:51:49 -04:00
.gitmodules roms/u-boot-sam460ex: Change to qemu git mirror and update 2018-04-10 10:05:38 +10:00
.gitpublish Add a git-publish configuration file 2018-03-05 09:03:17 +00:00
.mailmap maint: Add .mailmap entries for patches claiming list authorship 2018-04-09 16:36:40 +02:00
.shippable.yml shippable: Remove Debian 8 libfdt kludge 2018-05-11 14:33:40 +02:00
.travis.yml travis: reduce time taken for trace-backend testing 2018-06-14 20:24:07 +01:00
CODING_STYLE CODING_STYLE: Define our preferred form for multiline comments 2018-06-15 15:23:34 +01:00
COPYING
COPYING.LIB
COPYING.PYTHON scripts: add argparse module for Python 2.6 compatibility 2017-08-30 12:02:11 +01:00
Changelog Use HTTPS for qemu.org and other domains 2017-11-21 13:34:13 +00:00
HACKING HACKING: document preference for g_new instead of g_malloc 2018-05-20 08:32:09 +03:00
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 qobject: Move block-specific qdict code to block-qdict.c 2018-06-15 14:49:44 +02:00
Makefile ui: bugfixes for sdl and gtk 2018-06-14 14:04:14 +01:00
Makefile.objs hw/i2c: Add trace events 2018-06-08 13:15:33 +01:00
Makefile.target tcg: remove softfloat from --disable-tcg builds 2018-06-01 15:13:46 +02:00
README README: Fix typo 'git-publish' 2018-03-08 15:45:14 +00:00
VERSION Open 2.13 development tree 2018-04-26 11:48:27 +01:00
arch_init.c arch_init: sort architectures 2018-06-01 19:20:38 +03:00
balloon.c qapi: Empty out qapi-schema.json 2018-03-02 13:45:50 -06:00
block.c block: Add block-specific QDict header 2018-06-15 14:49:44 +02:00
blockdev-nbd.c Include less of the generated modular QAPI headers 2018-03-02 13:45:50 -06:00
blockdev.c block: Remove dead deprecation warning code 2018-06-15 14:49:44 +02:00
blockjob.c blockjob: Remove BlockJob.driver 2018-05-23 14:30:51 +02:00
bootdevice.c Makefile: Move bootdevice.o to common-obj-y 2017-07-04 14:39:27 +02:00
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
configure configure: Require Python 2.7 or newer 2018-06-08 16:40:49 -03:00
cpus-common.c *_run_on_cpu: introduce run_on_cpu_data type 2016-10-31 15:00:25 +01:00
cpus.c cpus: tcg: fix never exiting loop on unplug 2018-05-09 00:13:37 +02:00
device-hotplug.c block: Remove deprecated -drive option addr 2018-06-15 14:49:44 +02:00
device_tree.c device_tree: Increase FDT_MAX_SIZE to 1 MiB 2018-04-26 11:04:38 +01:00
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 dump: Fix build with newer gcc 2018-04-09 16:36:40 +02:00
exec.c exec.c: Handle IOMMUs in address_space_translate_for_iotlb() 2018-06-15 15:23:34 +01:00
gdbstub.c gdbstub: Prevent fd leakage 2018-06-01 15:14:31 +02:00
hmp-commands-info.hx sev/i386: hmp: add 'info sev' command 2018-03-13 17:36:05 +01:00
hmp-commands.hx block: Remove deprecated -drive geometry options 2018-06-15 14:49:44 +02:00
hmp.c migration/postcopy: Add max-postcopy-bandwidth parameter 2018-06-15 14:40:56 +01:00
hmp.h migration/hmp: add migrate_pause command 2018-05-15 22:13:08 +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 job: Add error message for failing jobs 2018-05-30 13:31:01 +02:00
memory.c iommu: Add IOMMU index argument to translate method 2018-06-15 15:23:34 +01:00
memory_ldst.inc.c Make address_space_translate{, _cached}() take a MemTxAttrs argument 2018-05-31 14:50:52 +01:00
memory_mapping.c Replace all occurances of __FUNCTION__ with __func__ 2018-01-22 09:46:18 +01:00
module-common.c all: Clean up includes 2016-02-04 17:41:30 +00:00
monitor.c * Linux header upgrade (Peter) 2018-06-01 18:24:16 +01:00
numa.c qmp: add set-numa-node command 2018-05-30 13:19:14 -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-doc.texi block: Remove deprecated -drive option serial 2018-06-15 14:49:44 +02:00
qemu-ga.texi qemu-ga: Remove stray 'q' in documentation 2016-10-28 18:17:23 +03:00
qemu-img-cmds.hx qemu-img: Remove deprecated -s snapshot_id_or_name option 2018-06-11 16:18:45 +02:00
qemu-img.c qemu-img: Fix assert when mapping unaligned raw file 2018-06-15 14:49:44 +02:00
qemu-img.texi qemu-img: Remove deprecated -s snapshot_id_or_name option 2018-06-11 16:18:45 +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 block: Remove deprecated -drive option serial 2018-06-15 14:49:44 +02:00
qemu-seccomp.c sandbox: disable -sandbox if CONFIG_SECCOMP undefined 2018-06-01 13:44:15 +02:00
qemu-tech.texi cli: add --preconfig option 2018-05-30 13:19:14 -03:00
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: add --preconfig option 2018-05-30 13:19:14 -03:00
qtest.c qtest: Don't perform side effects inside assertion 2017-09-15 09:05:19 +02:00
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.rc Use HTTPS for qemu.org and other domains 2017-11-21 13:34:13 +00:00
vl.c cli: Don't run early event loop if no --preconfig was specified 2018-06-11 14:25:49 -03:00

README

         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