QEMU With E2K User Support
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Emilio G. Cota 194125e3eb translate-all: protect TB jumps with a per-destination-TB lock
This applies to both user-mode and !user-mode emulation.

Instead of relying on a global lock, protect the list of incoming
jumps with tb->jmp_lock. This lock also protects tb->cflags,
so update all tb->cflags readers outside tb->jmp_lock to use
atomic reads via tb_cflags().

In order to find the destination TB (and therefore its jmp_lock)
from the origin TB, we introduce tb->jmp_dest[].

I considered not using a linked list of jumps, which simplifies
code and makes the struct smaller. However, it unnecessarily increases
memory usage, which results in a performance decrease. See for
instance these numbers booting+shutting down debian-arm:
                      Time (s)  Rel. err (%)  Abs. err (s)  Rel. slowdown (%)
------------------------------------------------------------------------------
 before                  20.88          0.74      0.154512                 0.
 after                   20.81          0.38      0.079078        -0.33524904
 GTree                   21.02          0.28      0.058856         0.67049808
 GHashTable + xxhash     21.63          1.08      0.233604          3.5919540

Using a hash table or a binary tree to keep track of the jumps
doesn't really pay off, not only due to the increased memory usage,
but also because most TBs have only 0 or 1 jumps to them. The maximum
number of jumps when booting debian-arm that I measured is 35, but
as we can see in the histogram below a TB with that many incoming jumps
is extremely rare; the average TB has 0.80 incoming jumps.

n_jumps: 379208; avg jumps/tb: 0.801099
dist: [0.0,1.0)|▄█▁▁▁▁▁▁▁▁▁▁▁ ▁▁▁▁▁▁ ▁▁▁  ▁▁▁     ▁|[34.0,35.0]

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-06-15 08:18:48 -10:00
accel translate-all: protect TB jumps with a per-destination-TB lock 2018-06-15 08:18:48 -10:00
audio
backends vhost-user: introduce shared vhost-user state 2018-05-24 21:14:11 +03:00
block block: Remove deprecated -drive option serial 2018-06-15 14:49:44 +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
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 translate-all: protect TB jumps with a per-destination-TB lock 2018-06-15 08:18:48 -10:00
dtc@e54388015a
fpu fpu/softfloat: Define floatN_silence_nan in terms of parts_silence_nan 2018-05-17 15:27:15 -07:00
fsdev
gdb-xml
hw Block layer patches: 2018-06-15 16:30:27 +01:00
include translate-all: protect TB jumps with a per-destination-TB lock 2018-06-15 08:18:48 -10:00
io Remove unnecessary variables for function return value 2018-05-20 08:48:13 +03:00
libdecnumber
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/next for 20180604 2018-06-04 12:54:00 +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
qapi rbd: New parameter key-secret 2018-06-15 14:49:44 +02:00
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
roms
scripts Miscellaneous patches for 2018-06-13 2018-06-14 11:35:22 +01:00
scsi
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: move tb_ctx.tb_phys_invalidate_count to tcg_ctx 2018-06-15 07:42:55 -10:00
tests qht: return existing entry when qht_insert fails 2018-06-15 07:42:55 -10:00
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 qht: return existing entry when qht_insert fails 2018-06-15 07:42:55 -10:00
.dir-locals.el
.editorconfig
.exrc
.gdbinit
.gitignore block: Ignore generated job QAPI files 2018-06-13 10:51:49 -04:00
.gitmodules
.gitpublish
.mailmap
.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
arch_init.c arch_init: sort architectures 2018-06-01 19:20:38 +03:00
balloon.c
block.c block: Add block-specific QDict header 2018-06-15 14:49:44 +02:00
blockdev-nbd.c
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
bt-host.c
bt-vhci.c
Changelog
CODING_STYLE CODING_STYLE: Define our preferred form for multiline comments 2018-06-15 15:23:34 +01:00
configure configure: Require Python 2.7 or newer 2018-06-08 16:40:49 -03:00
COPYING
COPYING.LIB
COPYING.PYTHON
cpus-common.c
cpus.c cpus: tcg: fix never exiting loop on unplug 2018-05-09 00:13:37 +02:00
device_tree.c
device-hotplug.c block: Remove deprecated -drive option addr 2018-06-15 14:49:44 +02:00
disas.c
dma-helpers.c
dump.c
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
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.hx block: Remove deprecated -drive geometry options 2018-06-15 14:49:44 +02:00
hmp.c migration/hmp: add migrate_pause command 2018-05-15 22:13:08 +02:00
hmp.h migration/hmp: add migrate_pause command 2018-05-15 22:13:08 +02:00
ioport.c
iothread.c
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
LICENSE
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
memory_ldst.inc.c Make address_space_translate{, _cached}() take a MemTxAttrs argument 2018-05-31 14:50:52 +01:00
memory_mapping.c
memory.c iommu: Add IOMMU index argument to translate method 2018-06-15 15:23:34 +01:00
module-common.c
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
qdict-test-data.txt
qemu-bridge-helper.c
qemu-doc.texi block: Remove deprecated -drive option serial 2018-06-15 14:49:44 +02:00
qemu-ga.texi
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
qemu-nbd.c block: Cancel job in bdrv_close_all() callers 2018-05-23 14:30:51 +02:00
qemu-nbd.texi
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
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
qemu.sasl
qmp.c cli: add --preconfig option 2018-05-30 13:19:14 -03:00
qtest.c
README
replication.c
replication.h
rules.mak tests/docker/Makefile.include: handle empty TARGET_LIST 2018-06-04 14:39:18 +08:00
thunk.c
tpm.c
trace-events job: Add lifecycle QMP commands 2018-05-23 14:30:51 +02:00
VERSION
version.rc
vl.c cli: Don't run early event loop if no --preconfig was specified 2018-06-11 14:25:49 -03:00

         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