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Ziyue Yang 508b4ecc39 gdbstub.c: fix GDB connection segfault caused by empty machines
This patch is to fix the segmentation fault caused by attaching
GDB to a QEMU instance initialized with "-M none" option.

The bug can be reproduced by

> ./qemu-system-x86_64 -M none -nographic -S -s

and attach a GDB to it by

> gdb -ex 'target remote :1234

The segmentation fault was originally caused by trying to read
the information about CPU when communicating with GDB. However,
it's impossible for any control flow to exist on an empty machine,
nor can CPU's be hot plugged to an empty machine later by QOM
commands. So I think simply disabling GDB connections on empty
machines makes sense.

Signed-off-by: Ziyue Yang <skiver.cloud.yzy@gmail.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2017-01-24 23:26:53 +03:00
audio
backends monitor: fix qmp/hmp query-memdev not reporting IDs of memory backends 2017-01-12 15:35:06 -02:00
block block: get rid of bdrv_io_unplugged_begin/end 2017-01-16 13:25:17 +00:00
bsd-user translate-all: add DEBUG_LOCKING asserts 2016-10-31 10:24:45 +01:00
contrib contrib: add libvhost-user 2016-12-16 01:14:38 +02:00
crypto crypto: support HMAC algorithms based on nettle 2016-12-22 09:24:59 +00:00
default-configs target-hppa: Add framework and enable compilation 2017-01-23 09:52:40 -08:00
disas disas/cris.c: Fix Coverity warning about unchecked NULL 2017-01-24 23:26:53 +03:00
docs docs: sync pci-ids.txt 2017-01-24 23:26:53 +03:00
dtc@65cc4d2748
fpu target-hppa: Add softfloat specializations 2017-01-23 09:52:40 -08:00
fsdev 9pfs: add cleanup operation in FileOperations 2016-11-23 13:53:34 +01:00
gdb-xml
hw scsi-disk: add 'fall through' comment to switch VERIFY cases 2017-01-24 23:26:53 +03:00
include win32: use glib gpoll if glib >= 2.50 2017-01-24 23:26:53 +03:00
io io: introduce a DNS resolver API 2017-01-23 15:32:46 +00:00
libdecnumber
linux-headers vhost: drop VHOST_F_DEVICE_IOTLB 2017-01-18 22:59:54 +02:00
linux-user linux-user: Add HPPA startup and main loop 2017-01-23 09:52:40 -08:00
migration io: change the QIOTask callback signature 2017-01-23 15:32:18 +00:00
nbd io: change the QIOTask callback signature 2017-01-23 15:32:18 +00:00
net -----BEGIN PGP SIGNATURE----- 2017-01-20 14:56:40 +00:00
pc-bios Update OpenBIOS images to ef8a14e built from submodule. 2016-11-24 21:26:00 +00:00
pixman@87eea99e44
po po: add missing translations in de, fr, it, zh 2016-12-14 18:47:19 +00:00
qapi qmp-events: move 'MIGRATION_PASS' doc to schema 2017-01-16 09:19:50 +01:00
qga qga: fix erroneous argument to strerror 2017-01-24 23:26:53 +03:00
qobject qdict: implement a qdict_crumple method for un-flattening a dict 2016-10-25 17:56:14 +02:00
qom object: make some funcs static 2017-01-24 23:26:53 +03:00
replay record/replay: add network support 2017-01-06 10:38:00 +08:00
roms Update OpenBIOS images to ef8a14e built from submodule. 2016-11-24 21:26:00 +00:00
scripts * QOM interface fix (Eduardo) 2017-01-20 16:42:07 +00:00
slirp slirp: support dynamic block size for TFTP transfers 2016-12-21 00:02:15 +01:00
stubs machine: Make possible_cpu_arch_ids() return const pointer 2017-01-23 21:25:37 -02:00
target Two s390x fixes: One for the kvm.c build failure, and one for a bug 2017-01-24 17:26:26 +00:00
tcg tcg/i386: Always use TZCNT when available 2017-01-17 12:02:08 -08:00
tests io: remove Error parameter from QIOTask thread worker 2017-01-23 15:32:19 +00:00
trace trace: Add event "guest_cpu_exit" 2017-01-16 13:40:56 +00:00
ui io: change the QIOTask callback signature 2017-01-23 15:32:18 +00:00
util win32: use glib gpoll if glib >= 2.50 2017-01-24 23:26:53 +03:00
.dir-locals.el
.exrc
.gitignore build-sys: add qapi doc generation targets 2017-01-16 10:11:43 +01:00
.gitmodules ppc: add skiboot firmware for the pnv platform 2016-10-28 09:36:58 +11:00
.mailmap
.travis.yml travis: add Trusty with clang stable build 2017-01-12 10:04:17 +00:00
accel.c clean-up: removed duplicate #includes 2016-10-28 18:17:24 +03:00
aio-posix.c aio-posix: remove walking_handlers, protecting AioHandler list with list_lock 2017-01-16 13:25:18 +00:00
aio-win32.c aio-win32: remove walking_handlers, protecting AioHandler list with list_lock 2017-01-16 13:25:18 +00:00
arch_init.c arch_init: Remove unnecessary default_config_files table 2017-01-23 21:25:36 -02:00
async.c async: optimize aio_bh_poll 2017-01-16 13:25:18 +00:00
atomic_template.h tcg: Add atomic128 helpers 2016-10-26 08:29:01 -07:00
balloon.c
block.c block: remove dead check 2017-01-24 23:26:53 +03:00
blockdev-nbd.c nbd: set name for all I/O channels created 2016-10-27 09:13:10 +02:00
blockdev.c blockjob: refactor backup_start as backup_job_create 2016-11-14 22:47:34 -05:00
blockjob.c blockjob: add block_job_start 2016-11-14 22:47:34 -05:00
bootdevice.c
bt-host.c
bt-vhci.c
Changelog
CODING_STYLE
configure hppa-linux target support 2017-01-24 09:52:42 +00:00
COPYING
COPYING.LIB
cpu-exec-common.c tcg: Add EXCP_ATOMIC 2016-10-26 08:29:00 -07:00
cpu-exec.c log: Add locking to large logging blocks 2016-11-01 10:29:03 -06:00
cpus-common.c *_run_on_cpu: introduce run_on_cpu_data type 2016-10-31 15:00:25 +01:00
cpus.c Plumb the HAXM-based hardware acceleration support 2017-01-19 22:07:46 +01:00
cputlb.c cputlb: drop flush_global flag from tlb_flush 2017-01-13 14:24:37 +00:00
device-hotplug.c
device_tree.c
disas.c Revert "Remove remainders of HPPA backend" 2017-01-22 18:13:56 -08:00
dma-helpers.c dma-helpers: explicitly pass alignment into DMA helpers 2016-10-27 16:29:13 -04:00
dump.c
exec.c * QOM interface fix (Eduardo) 2017-01-20 16:42:07 +00:00
gdbstub.c gdbstub.c: fix GDB connection segfault caused by empty machines 2017-01-24 23:26:53 +03:00
HACKING HACKING: document #include order 2017-01-03 16:38:47 +00:00
hax-stub.c Plumb the HAXM-based hardware acceleration support 2017-01-19 22:07:46 +01:00
hmp-commands-info.hx
hmp-commands.hx COLO: Add 'x-colo-lost-heartbeat' command to trigger failover 2016-10-30 15:17:39 +05:30
hmp.c monitor: fix qmp/hmp query-memdev not reporting IDs of memory backends 2017-01-12 15:35:06 -02:00
hmp.h COLO: Add 'x-colo-lost-heartbeat' command to trigger failover 2016-10-30 15:17:39 +05:30
iohandler.c event_notifier: cleanups around event_notifier_set_handler 2017-01-16 17:52:35 +01:00
ioport.c
iothread.c iothread: add poll-grow and poll-shrink parameters 2017-01-03 16:38:50 +00:00
kvm-all.c *_run_on_cpu: introduce run_on_cpu_data type 2016-10-31 15:00:25 +01:00
kvm-stub.c
LICENSE
main-loop.c main-loop: Suppress I/O thread warning under qtest 2016-11-02 09:28:57 +01:00
MAINTAINERS x86, machine, numa queue (2017-01-23) 2017-01-24 15:39:09 +00:00
Makefile Makefile: Add qemu-doc.txt to distclean and dependencies 2017-01-24 14:32:05 +00:00
Makefile.objs virtio, vhost, pc: fixes 2017-01-09 15:30:45 +00:00
Makefile.target Plumb the HAXM-based hardware acceleration support 2017-01-19 22:07:46 +01:00
memory.c memory: handle alias for iommu notifier 2017-01-10 05:56:59 +02:00
memory_ldst.inc.c exec: introduce memory_ldst.inc.c 2016-12-22 16:00:23 +01:00
memory_mapping.c memory: Replace skip_dump flag with "ram_device" 2016-10-31 09:53:03 -06:00
module-common.c
monitor.c * QOM interface fix (Eduardo) 2017-01-20 16:42:07 +00:00
numa.c ramblock-notifier: new 2017-01-16 17:52:35 +01:00
os-posix.c
os-win32.c
page_cache.c
qapi-schema.json sockets: add ability to disable DNS resolution for InetSocketAddress 2017-01-23 15:32:17 +00:00
qdev-monitor.c qdev: add function qdev_set_id() 2016-11-22 10:29:37 -08:00
qdict-test-data.txt
qemu-bridge-helper.c
qemu-char.c io: change the QIOTask callback signature 2017-01-23 15:32:18 +00:00
qemu-doc.texi Fix documentation and some comments (article, grammar) 2017-01-24 23:26:52 +03:00
qemu-ga.texi qemu-ga: Remove stray 'q' in documentation 2016-10-28 18:17:23 +03:00
qemu-img-cmds.hx
qemu-img.c qemu-img: remove dead check 2017-01-24 23:26:53 +03:00
qemu-img.texi
qemu-io-cmds.c trivial patches for 2016-10-28 2016-10-31 11:58:30 +00:00
qemu-io.c
qemu-nbd.c nbd: Add qemu-nbd -D for human-readable description 2016-11-02 09:28:55 +01:00
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-options-wrapper.h hxtool: emit Texinfo headings as @subsection 2017-01-16 17:52:35 +01:00
qemu-options.h
qemu-options.hx Drop duplicate display option documentation 2017-01-24 23:26:53 +03:00
qemu-seccomp.c
qemu-tech.texi
qemu-timer.c qemu-timer: check active_timers outside lock/event 2016-12-22 16:00:24 +01:00
qemu.nsi
qemu.sasl
qmp.c clean-up: removed duplicate #includes 2016-10-28 18:17:24 +03:00
qtest.c libqtest: handle zero length memwrite/memread 2017-01-12 10:45:59 +00:00
README README: Add linux to macOS build info 2017-01-24 23:26:52 +03:00
replication.c
replication.h
rules.mak build-sys: add qapi doc generation targets 2017-01-16 10:11:43 +01:00
softmmu_template.h cputlb: Tidy some macros 2016-10-26 08:29:00 -07:00
spice-qemu-char.c char: remove explicit_be_open from CharDriverState 2016-10-24 15:46:11 +02:00
tcg-runtime.c tcg: Add opcode for ctpop 2017-01-10 08:48:56 -08:00
tci.c
thread-pool.c
thunk.c
tpm.c
trace-events trace: Add event "guest_cpu_exit" 2017-01-16 13:40:56 +00:00
translate-all.c translate-all: Avoid -Werror=switch-bool 2017-01-08 09:48:34 -08:00
translate-all.h
translate-common.c
user-exec-stub.c stubs: group stubs for user-mode emulation 2017-01-16 17:52:35 +01:00
user-exec.c
VERSION Open 2.9 development tree 2016-12-20 16:20:16 +00:00
version.rc
vl.c arch_init: Remove unnecessary default_config_files table 2017-01-23 21:25:36 -02:00
xen-common-stub.c
xen-common.c xen: Fix xenpv machine initialisation 2016-11-08 11:17:30 -08:00
xen-hvm-stub.c
xen-hvm.c xen: ignore direction in bufioreq handling 2016-11-28 11:26:29 -08:00
xen-mapcache.c ramblock-notifier: new 2017-01-16 17:52:35 +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.


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:

  http://qemu-project.org/Hosts/Linux
  http://qemu-project.org/Hosts/Mac
  http://qemu-project.org/Hosts/W32


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

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

   git clone git://git.qemu-project.org/qemu.git

When submitting patches, the preferred 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

  http://qemu-project.org/Contribute/SubmitAPatch
  http://qemu-project.org/Contribute/TrivialPatches


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:

  http://qemu-project.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
   http://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:

  http://qemu-project.org/Contribute/StartHere

-- End