This patch implements a new chardev backend `hub` device, which
aggregates input from multiple backend devices and forwards it to a
single frontend device. Additionally, `hub` device takes the output
from the frontend device and sends it back to all the connected
backend devices. This allows for seamless interaction between
different backend devices and a single frontend interface.
The idea of the change is trivial: keep list of backend devices
(up to 4), init them on demand and forward data buffer back and
forth.
The following is QEMU command line example:
-chardev pty,path=/tmp/pty,id=pty0 \
-chardev vc,id=vc0 \
-chardev hub,id=hub0,chardevs.0=pty0,chardevs.1=vc0 \
-device virtconsole,chardev=hub0 \
-vnc 0.0.0.0:0
Which creates 2 backend devices: text virtual console (`vc0`) and a
pseudo TTY (`pty0`) connected to the single virtio hvc console with
the backend aggregator (`hub0`) help. `vc0` renders text to an image,
which can be shared over the VNC protocol. `pty0` is a pseudo TTY
backend which provides biderectional communication to the virtio hvc
console.
'chardevs.N' list syntax is used for the sake of compatibility with
the representation of JSON lists in 'key=val' pairs format of the
util/keyval.c, despite the fact that modern QAPI way of parsing,
namely qobject_input_visitor_new_str(), is not used. Choice of keeping
QAPI list syntax may help to smoothly switch to modern parsing in the
future.
Signed-off-by: Roman Penyaev <r.peniaev@gmail.com>
Reviewed-by: "Marc-André Lureau" <marcandre.lureau@redhat.com>
Cc: qemu-devel@nongnu.org
Message-ID: <20250123085327.965501-3-r.peniaev@gmail.com>
The 'reconnect' option only allows to specify the time in seconds,
which is way too long for certain workflows.
We have a lightweight disk backend server, which takes about 20ms to
live update, but due to this limitation in QEMU, previously the guest
disk controller would hang for one second because it would take this
long for QEMU to reinitialize the socket connection.
Introduce a new option called 'reconnect-ms', which is the same as
'reconnect', except the value is treated as milliseconds. These are
mutually exclusive and specifying both results in an error.
'reconnect' is also deprecated by this commit to make it possible to
remove it in the future as to not keep two options that control the
same thing.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Acked-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Acked-by: Markus Armbruster <armbru@redhat.com>
Tested-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240913094604.269135-1-d-tatianin@yandex-team.ru>
The function qemu_chr_fe_init already treats be->fe_open as a bool and
if it acts like a bool it should be one. While we are at it make the
variable name more descriptive and add kdoc decorations.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20231211145959.93759-1-alex.bennee@linaro.org>
In commit 6f974c843c ("gtk: overwrite the console.c char driver"), I
shared the VC console parse handler with GTK. And later on in commit
d8aec9d9 ("display: add -display spice-app launching a Spice client"),
I also used it to handle spice-app VC.
This is not necessary, the VC console options (width/height/cols/rows)
are specific, and unused by tty-level GTK/Spice VC.
This is not a breaking change, as those options are still being parsed
by QAPI ChardevVC. Adjust the documentation about it.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20230830093843.3531473-44-marcandre.lureau@redhat.com>
Make source buffers const for char be write functions.
This allows using buffers returned by fifo as buf parameter and source buffer
should not be changed by write functions anyway.
Signed-off-by: Arwed Meyer <arwed.meyer@gmx.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220911181840.8933-3-arwed.meyer@gmx.de>
Leading underscores are ill-advised because such identifiers are
reserved. Trailing underscores are merely ugly. Strip both.
Our header guards commonly end in _H. Normalize the exceptions.
Macros should be ALL_CAPS. Normalize the exception.
Done with scripts/clean-header-guards.pl.
include/hw/xen/interface/ and tools/virtiofsd/ left alone, because
these were imported from Xen and libfuse respectively.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20220506134911.2856099-3-armbru@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
One less qemu-specific macro. It also helps to make some headers/units
only depend on glib, and thus moved in standalone projects eventually.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
Add a new chardev backend which allows D-Bus client to handle the
chardev stream & events.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
"chr_option_parsed" is only implemented by the "mux" chardev, we can
specialize the code there to avoid the needless generic class method.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Since commit 9894dc0cdc "char: convert
from GIOChannel to QIOChannel", the first argument to the watch callback
can actually be a QIOChannel, which is not a GIOChannel (but a QEMU
Object).
Even though we never used that pointer, change the callback type to warn
the users. Possibly a better fix later, we may want to store the
callback and call it from intermediary functions.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
When changing from chardev-socket (which supports yank) to
chardev-socket again, it fails, because the new chardev attempts
to register a new yank instance. This in turn fails, as there
still is the yank instance from the current chardev. Also,
the old chardev shouldn't unregister the yank instance when it
is freed.
To fix this, now the new chardev only registers a yank instance if
the current chardev doesn't support yank and thus hasn't registered
one already. Also, when the old chardev is freed, it now only
unregisters the yank instance if the new chardev doesn't need it.
If the initialization of the new chardev fails, it still has
chr->handover_yank_instance set and won't unregister the yank
instance when it is freed.
s->registered_yank is always true here, as chardev-change only works
on user-visible chardevs and those are guraranteed to register a
yank instance as they are initialized via
chardev_new()
qemu_char_open()
cc->open() (qmp_chardev_open_socket()).
Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Li Zhang <li.zhang@cloud.ionos.com>
Message-Id: <9637888d7591d2971975188478bb707299a1dc04.1617127849.git.lukasstraub2@web.de>
machine_init_done is not the right flag to check when preconfig
is taken into account; for example "./qemu-system-x86_64 -serial
mon:stdio -preconfig" does not print the QEMU monitor header until after
exit_preconfig. Add back a custom bool for mux character devices. This
partially undoes commit c7278b4355 ("chardev: introduce chr_machine_done
hook", 2018-03-12), but it keeps the cleaner logic using a function
pointer in ChardevClass.
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Initialize spice before chardevs. That allows to register the spice
chardevs directly in the init function and removes the need to maintain
a linked list of chardevs just for registration.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20201014121120.13482-5-kraxel@redhat.com
