qemu/include
Roman Penyaev b66ed23238 chardev/char-hub: implement backend chardev aggregator
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>
2025-02-03 13:57:08 +04:00
..
authz Prefer 'on' | 'off' over 'yes' | 'no' for bool options 2021-01-29 17:07:53 +00:00
block include: Include missing 'qemu/clang-tsa.h' header 2024-12-20 17:44:57 +01:00
chardev chardev/char-hub: implement backend chardev aggregator 2025-02-03 13:57:08 +04:00
crypto crypto: Introduce SM3 hash hmac pbkdf algorithm 2024-11-05 18:37:18 +00:00
disas disas: Fix build against Capstone v6 (again) 2024-11-05 10:09:59 +00:00
exec Migration pull request 2025-01-30 10:29:22 -05:00
fpu fpu: Fix a comment in softfloat-types.h 2025-01-28 18:40:19 +00:00
gdbstub gdbstub/helpers: Introduce ldtul_$endian_p() helpers 2024-10-15 11:55:09 -03:00
hw Misc HW patches 2025-02-02 11:09:03 -05:00
io qio: add support for SO_PEERCRED for socket channel 2024-07-22 13:47:41 +02:00
libdecnumber Replace config-time define HOST_WORDS_BIGENDIAN 2022-04-06 10:50:37 +02:00
migration migration: cpr-transfer mode 2025-01-29 11:56:24 -03:00
monitor monitor: Remove obsolete stubs 2024-06-30 19:51:44 +03:00
net net: checksum: Convert data to void * 2024-11-25 13:59:50 +08:00
qapi qerror: QERR_PROPERTY_VALUE_OUT_OF_RANGE is no longer used, drop 2024-10-18 15:03:35 +02:00
qemu backends/hostmem-shm: factor out allocation of "anonymous shared memory with an fd" 2025-01-29 11:43:03 -03:00
qom qom: remove unused field 2025-01-10 23:34:44 +01:00
scsi hw/ufs: Support for UFS logical unit 2023-09-07 14:01:29 -04:00
semihosting semihosting/console: Avoid including 'cpu.h' 2025-01-17 10:44:00 +00:00
standard-headers hw/acpi: Add vmclock device 2025-01-15 17:43:24 -05:00
system system/runstate: Fix regression, clarify BQL status of exit notifiers 2025-01-15 18:05:19 +00:00
tcg tcg: Document tb_lookup() and tcg_tb_lookup() 2025-01-17 08:24:43 -08:00
ui ui/input-legacy.c: remove unused legacy qemu_add_kbd_event_handler() function 2024-11-08 11:06:42 +01:00
user user: Move various declarations out of 'exec/exec-all.h' 2024-12-20 17:44:57 +01:00
elf.h util: spelling fixes 2023-08-31 19:47:43 +02:00
glib-compat.h Bump minimum glib version to v2.66 2024-05-14 12:46:24 +02:00
qemu-io.h Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
qemu-main.h ui & main loop: Redesign of system-specific main thread event handling 2024-12-31 21:21:34 +01:00