Commit Graph

269 Commits

Author SHA1 Message Date
Gerd Hoffmann
60d95386ab chardev: fix "info chardev" output
Fill unset CharDriverState->filename with the backend name, so
'info chardev' will return at least the chardev type.  Don't
touch it in case the chardev init function filled it already,
like the socket+pty chardevs do for example.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-05-27 12:47:28 +02:00
Gerd Hoffmann
3022e6b472 Revert "chardev: Get filename for new qapi backend"
Does not handle chardevs created via chardev-add monitor command.

This reverts commit 2b22002599.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-05-27 12:47:17 +02:00
Lei Li
2b22002599 chardev: Get filename for new qapi backend
This patch sets the filename when the new qapi backend
init from opts.

The previous patch and discussions as link below:

http://patchwork.ozlabs.org/patch/243896/

If anyone who have better idea to fix this please let
me know your suggestions.

Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
Message-id: 1369132079-11377-3-git-send-email-lilei@linux.vnet.ibm.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-22 07:40:10 -05:00
Lei Li
6a85e60cb9 chardev: Make the name of memory device consistent
Now we have memory char device, but the backend name of it
is a little confusion. We actually register it by 'memory', but
the description in qemu-option, the name of open functions
and the new api backend called it 'ringbuf'. It should keep
consistent. This patch named it all to 'memory'.

Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1369132079-11377-2-git-send-email-lilei@linux.vnet.ibm.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-22 07:40:10 -05:00
Peter Crosthwaite
3d1bba2091 glib: Fix some misuses of gsize/size_t types
This unbreaks cross compile builds:

configure --target-list="i386-softmmu" --cpu=i386

When building on a 64bit machine.

Reported-by: David Holsgrove <david.holsgrove@xilinx.com>
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Message-id: 926326e96fd8685d74e9d5bf430fe4ad97a55289.1369191585.git.peter.crosthwaite@xilinx.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-22 07:40:09 -05:00
Lei Li
08d0ab3fe6 chardev: Make consistent with udp device for new qapi backend
When register and open a chardev udp, the backend name should be udp
not dgram, and we do not have backend dgram in the chardev list. This
patch makes the new qapi udp backend consistent with the original
udp device.

Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
Message-id: 1369032665-18159-2-git-send-email-lilei@linux.vnet.ibm.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-20 08:20:07 -05:00
Paolo Bonzini
7791dba3ec portability: pty.h is glibc-specific
This should fix building the GTK+ front-end on BSDs.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1368533121-30796-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-14 08:53:18 -05:00
Hans de Goede
79f2007578 qemu-char: Set foo_tag = 0 when returning FALSE from callbacks
While reviewing some patches I found this problem where tcp_chr_accept
does not clear listen_tag when returning FALSE, leading to a double
g_source_remove of the underlying source. Not really a problem unless the id
gets re-used in between, but still something we should fix.

While at it I've also reviewed all the other code in qemu-char.c for
similar problems and found that pty_chr_timer has the same problem.

Cc: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1366890782-10311-1-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-25 14:45:47 -05:00
Paolo Bonzini
2b316774f6 qemu-char: do not operate on sources from finalize callbacks
Due to a glib bug, the finalize callback is called with the GMainContext
lock held.  Thus, any operation on the context from the callback will
cause recursive locking and a deadlock.  This happens, for example,
when a client disconnects from a socket chardev.

The fix for this is somewhat ugly, because we need to forego polymorphism
and implement our own function to destroy IOWatchPoll sources.  The
right thing to do here would be child sources, but we support older
glib versions that do not have them.  Not coincidentially, glib developers
found and fixed the deadlock as part of implementing child sources.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Message-id: 1366385529-10329-5-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-22 08:52:21 -05:00
Paolo Bonzini
cdbf6e1659 qemu-char: correct return value from chr_read functions
Even if a CharDriverState's source is blocked by the front-end,
it must not be dropped. The IOWatchPoll that wraps it will take
care of adding and removing it to the main loop.  Only remove
the source when the channel is closed; and in that case, make sure
that the wrapping IOWatchPoll is removed too.

These should just be theoretical bugs.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1366385529-10329-4-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-22 08:52:20 -05:00
Paolo Bonzini
85a67692d0 qemu-char: simplify pty polling
There is no need to use a timer and pty_chr_read to detect a connected
pty.  It is simpler to just call g_poll periodically and check for POLLHUP.
It is done once per second, and only if the pty is disconnected, so it
is cheap enough.

Tested with "-monitor pty" and "-serial mon:pty", both of which work
correctly and do not freeze QEMU.  (How to test ptys?  "socat -,raw,echo=0
/dev/pts/4,raw").

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1366385529-10329-3-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-22 08:52:20 -05:00
Paolo Bonzini
910b63682e qemu-char: use consistent idiom for removing sources
Always check that the source is active, and zero the tag afterwards.

The occurrence in pty_chr_state will trigger with the next patch, the
others are just theoretical.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1366385529-10329-2-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-22 08:52:20 -05:00
Anthony Liguori
4ceb193d30 Merge remote-tracking branch 'bonzini/hw-dirs' into staging
* bonzini/hw-dirs:
  exec: remove useless declarations from memory-internal.h
  memory: move core typedefs to qemu/typedefs.h
  include: avoid useless includes of exec/ headers
  sysemu: avoid proliferation of include/ subdirectories
  tpm: reorganize headers and split hardware part
  configure: fix TPM logic
  acpi.h: make it self contained
  acpi: move declarations from pc.h to acpi.h
  hw: Add lost ARM core again
  Fix failure to create q35 machine
  Add linux-headers to QEMU_INCLUDES
  arm: fix location of some include files

Conflicts:
	configure

aliguori: trivial conflict in configure output

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-15 17:06:04 -05:00
Paolo Bonzini
dccfcd0e5f sysemu: avoid proliferation of include/ subdirectories
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-04-15 18:19:25 +02:00
Paolo Bonzini
0ca5aa4f4c qemu-char: another io_add_watch_poll fix
After attaching the source, we have to remove the reference we hold
to it, because we do not hold anymore a pointer to the source.

If we do not do this, removing the source will not finalize it and
will not drop the "real" I/O watch source.

This showed up when backporting the new flow control patches to older
versions of QEMU that still used select.  The whole select then failed
with EBADF (poll instead will reporting POLLNVAL on a single pollfd)
and QEMU froze.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1365600207-21685-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-15 10:22:05 -05:00
Paolo Bonzini
1e885b2527 qemu-char: really fix behavior on can_read = 0
I misread the glib manual, g_source_remove does not let you re-attach
the source later.  This behavior (called "blocking" the source in glib)
is present in glib's source code, but private and not available outside
glib; hence, we have to resort to re-creating the source every time.

In fact, g_source_remove and g_source_destroy are the same thing,
except g_source_destroy is O(1) while g_source_remove scans a potentially
very long list of GSources in the current main loop.  Ugh.  Better
use g_source_destroy explicitly, and leave "tags" to those dummies who
cannot track their pointers' lifetimes.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1365426195-12596-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-08 10:38:41 -05:00
Paolo Bonzini
d185c094b4 qemu-char: eliminate busy waiting on can_read returning zero
The character backend refactoring introduced an undesirable busy wait.
The busy wait happens if can_read returns zero and there is data available
on the character device's file descriptor.  Then, the I/O watch will
fire continuously and, with TCG, the CPU thread will never run.

    1) Char backend asks front end if it can write
    2) Front end says no
    3) poll() finds the char backend's descriptor is available
    4) Goto (1)

What we really want is this (note that step 3 avoids the busy wait):

    1) Char backend asks front end if it can write
    2) Front end says no
    3) poll() goes on without char backend's descriptor
    4) Goto (1) until qemu_chr_accept_input() called

    5) Char backend asks front end if it can write
    6) Front end says yes
    7) poll() finds the char backend's descriptor is available
    8) Backend handler called

After this patch, the IOWatchPoll source and the watch source are
separated.  The IOWatchPoll is simply a hook that runs during the prepare
phase on each main loop iteration.  The hook adds/removes the actual
source depending on the return value from can_read.

A simple reproducer is

    qemu-system-i386 -serial mon:stdio

... followed by banging on the terminal as much as you can. :)  Without
this patch, emulation will hang.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1365177573-11817-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-05 12:53:07 -05:00
Luiz Capitulino
4bf0bb8014 chardev: drop the Memory chardev driver
It's not used anymore since the last commit.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
2013-04-05 08:42:29 -04:00
Hans de Goede
456d606923 qemu-char: Call fe_claim / fe_release when not using qdev chr properties
chardev-frontends need to explictly check, increase and decrement the
avail_connections "property" of the chardev when they are not using a
qdev-chardev-property for the chardev.

This fixes things like:
qemu-kvm -chardev stdio,id=foo -device isa-serial,chardev=foo \
  -mon chardev=foo

Working, where they should fail. Most of the changes here are due to
old hardware emulation code which is using serial_hds directly rather then
a qdev-chardev-property.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364412581-3672-3-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-04 19:21:25 -05:00
Hans de Goede
44c473decd qemu-char: Add qemu_chr_fe_claim / _release helper functions
Add qemu_chr_fe_claim / _release helper functions for properly dealing with
avail_connections.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364412581-3672-2-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-04-04 19:21:25 -05:00
Anthony Liguori
162cbbd173 Merge remote-tracking branch 'luiz/queue/qmp' into staging
# By Stefan Hajnoczi
# Via Luiz Capitulino
* luiz/queue/qmp:
  chardev: clear O_NONBLOCK on SCM_RIGHTS file descriptors
  qemu-socket: set passed fd non-blocking in socket_connect()
  net: ensure "socket" backend uses non-blocking fds
  oslib-posix: rename socket_set_nonblock() to qemu_set_nonblock()
2013-04-02 14:07:35 -05:00
Stefan Hajnoczi
9b938c7262 chardev: clear O_NONBLOCK on SCM_RIGHTS file descriptors
When we receive a file descriptor over a UNIX domain socket the
O_NONBLOCK flag is preserved.  Clear the O_NONBLOCK flag and rely on
QEMU file descriptor users like migration, SPICE, VNC, block layer, and
others to set non-blocking only when necessary.

This change ensures we don't accidentally expose O_NONBLOCK in the QMP
API.  QMP clients should not need to get the non-blocking state
"correct".

A recent real-world example was when libvirt passed a non-blocking TCP
socket for migration where we expected a blocking socket.  The source
QEMU produced a corrupted migration stream since its code did not cope
with non-blocking sockets.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2013-04-02 11:47:37 -04:00
Stefan Hajnoczi
f9e8cacc55 oslib-posix: rename socket_set_nonblock() to qemu_set_nonblock()
The fcntl(fd, F_SETFL, O_NONBLOCK) flag is not specific to sockets.
Rename to qemu_set_nonblock() just like qemu_set_cloexec().

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2013-04-02 11:47:37 -04:00
Anthony Liguori
684a096eaf qemu-char: rewrite io_channel_send_all and drop the '_all' suffix
The current code is oddly written and have equally odd semantics.
Despite the '_all' suffix, upon EAGAIN the result will be a partial
write but instead of returning the partial write, we return EAGAIN.

Change the behavior to write as much as we can until we get an EAGAIN
returning a partial write if we do.

Reported-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Message-id: 1364575190-731-1-git-send-email-aliguori@us.ibm.com
2013-04-02 08:13:58 -05:00
Hans de Goede
a59bcd31c9 qemu-char: add_handlers: Don't re-send the be_open event on unregister
Resending the be_open event only is useful when a frontend is registering, not
when it is unregistering.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364292483-16564-9-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-27 10:26:49 -05:00
Hans de Goede
85d91e3295 qemu-char: Move incrementing of avail_connections to qdev-properties-system
The decrement of avail_connections is done in qdev-properties-system move
the increment there too for proper balancing of the calls.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364292483-16564-8-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-27 10:26:49 -05:00
Hans de Goede
574b711a92 qemu-char: Consolidate guest_close/guest_open into a set_fe_open callback
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364292483-16564-7-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-27 10:26:49 -05:00
Hans de Goede
8e25daa87a qemu-char: Cleanup: consolidate fe_open/fe_close into fe_set_open
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364292483-16564-6-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-27 10:26:49 -05:00
Hans de Goede
190832289f qemu-char: Automatically do fe_open / fe_close on qemu_chr_add_handlers
Most frontends can't really determine if the guest actually has the frontend
side open. So lets automatically generate fe_open / fe_close as soon as a
frontend becomes ready (as signalled by calling qemu_chr_add_handlers) /
becomes non ready (as signalled by setting all handlers to NULL).

And allow frontends which can actually determine if the guest is listening to
opt-out of this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364292483-16564-5-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-27 10:26:49 -05:00
Hans de Goede
c0c4bd2cfa qemu-char: Add fe_open tracking
Add tracking of the fe_open state to struct CharDriverState.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364292483-16564-4-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-27 10:26:49 -05:00
Hans de Goede
fee204fd46 qemu-char: Rename qemu_chr_generic_open to qemu_chr_be_generic_open
To better reflect that it is for handling a backend being opened.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364292483-16564-3-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-27 10:26:49 -05:00
Hans de Goede
16665b943b qemu-char: Rename opened to be_open
Rename the opened variable to be_open to reflect that it contains the
opened state of the backend.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364292483-16564-2-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-27 10:26:48 -05:00
Anthony Liguori
cd18720a29 char: introduce a blocking version of qemu_chr_fe_write
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-26 10:08:07 -05:00
Kevin Wolf
2c8a59422c char: Fix return type of qemu_chr_fe_add_watch()
qemu_chr_fe_add_watch() can return negative errors, therefore it must
not have an unsigned return type. For consistency with other
qemu_chr_fe_* functions, this uses a standard C int instead of glib
types.

In situations where qemu_chr_fe_add_watch() is falsely assumed to have
succeeded, the serial ports would go into a state where it never becomes
ready for transmitting more data; this is fixed by this patch.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-19 07:56:07 -05:00
Igor Mitsyanko
e5545854dd qemu-char.c: fix waiting for telnet connection message
Current colon position in "waiting for telnet connection" message template
produces messages like:
QEMU waiting for connection on: telnet::127.0.0.16666,server

After moving a colon to the right, we will get a correct messages like:
QEMU waiting for connection on: telnet:127.0.0.1:6666,server

Signed-off-by: Igor Mitsyanko <i.mitsyanko@gmail.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:47 +01:00
Gerd Hoffmann
3ecc059dcd chardev: add udp support to qapi
This patch adds 'udp' support to qapi.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
1da48c658a chardev: add memory (ringbuf) support to qapi
This patch adds 'memory' support to qapi and also switches over
the memory chardev initialization to the new qapi code path.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
702ec69cc1 chardev: add vc support to qapi
This patch adds 'vc' support to qapi and also switches over the
vc chardev initialization to the new qapi code path.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
cd153e2aa2 chardev: add spice support to qapi
This patch adds 'spicevmc' and 'spiceport' support to qapi and also
switches over the spice chardev initialization to the new qapi code
path.
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
548cbb36f4 chardev: add pipe support to qapi
This patch adds 'pipe' support to qapi and also switches over the
pipe chardev initialization to the new qapi code path.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
d9ac374f0d chardev: add console support to qapi
This patch adds 'console' support to qapi and also switches over the
console chardev initialization to the new qapi code path.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
e68c595866 chardev: switch pty init to qapi
This patch switches over the pty chardev initialization
to the new qapi code path.

Bonus: Taking QemuOpts out of the loop allows some nice
cleanups along the way.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
dc37509769 chardev: switch parallel init to qapi
This patch switches over the parallel chardev initialization
to the new qapi code path.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
0f1cb51da7 chardev: switch serial/tty init to qapi
This patch switches over the serial chardev initialization
to the new qapi code path.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
7c358031ea chardev: add stdio support to qapi
This patch adds 'stdio' support to qapi and also switches over the
stdio chardev initialization to the new qapi code path.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
846e2e4938 chardev: switch file init to qapi
This patch switches over the 'file' chardev initialization
to the new qapi code path.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
2d57286da6 chardev: add braille support to qapi
This patch adds 'braille' support to qapi and also switches over
the braille chardev initialization to the new qapi code path.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
f5a51cab2a chardev: add msmouse support to qapi
This patch adds 'msmouse' support to qapi and also switches over
the msmouse chardev initialization to the new qapi code path.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:46 +01:00
Gerd Hoffmann
80dca9e643 chardev: switch null init to qapi
This patch switches over the 'null' chardev initialization
to the new qapi code path.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2013-03-13 10:27:45 +01:00
Gerd Hoffmann
edb2fb3cc8 chardev: add mux chardev support to qapi
This adds mux chardev support to the qapi and also makes the qapi-based
chardev creation path handle the "mux=on" option correctly.
2013-03-13 10:27:45 +01:00