From 1a29cc8f5ebd657e159dbe4be340102595846d42 Mon Sep 17 00:00:00 2001 From: Anton Nefedov Date: Thu, 6 Jul 2017 15:09:00 +0300 Subject: [PATCH] serial: chardev hotswap support This allows to change the port's backend runtime, e.g. change it from file to a socket making it possible to establish a debug session with WinDbg > qemu-system [..] -chardev file,id=charchannel2,path=/tmp/charchannel2 \ -device isa-serial,chardev=charchannel2,id=channel2 QEMU 2.9.50 monitor - type 'help' for more information (qemu) chardev-change charchannel2 \ socket,host=127.0.0.1,port=4242,server,nowait For a backend change, a number of ioctls has to be replayed to sync the current setup of a frontend to a backend tty. This is hopefully enough so we don't have to track, store and replay the whole original control byte sequence. Signed-off-by: Anton Nefedov Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <1499342940-56739-14-git-send-email-anton.nefedov@virtuozzo.com> Signed-off-by: Paolo Bonzini --- hw/char/serial.c | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/hw/char/serial.c b/hw/char/serial.c index 09157f981f..9aec6c60d8 100644 --- a/hw/char/serial.c +++ b/hw/char/serial.c @@ -891,6 +891,34 @@ static void serial_reset(void *opaque) s->msr &= ~UART_MSR_ANY_DELTA; } +static int serial_be_change(void *opaque) +{ + SerialState *s = opaque; + + qemu_chr_fe_set_handlers(&s->chr, serial_can_receive1, serial_receive1, + serial_event, serial_be_change, s, NULL, true); + + serial_update_parameters(s); + + qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_BREAK, + &s->last_break_enable); + + s->poll_msl = (s->ier & UART_IER_MSI) ? 1 : 0; + serial_update_msl(s); + + if (s->poll_msl >= 0 && !(s->mcr & UART_MCR_LOOP)) { + serial_update_tiocm(s); + } + + if (s->watch_tag > 0) { + g_source_remove(s->watch_tag); + s->watch_tag = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP, + serial_watch_cb, s); + } + + return 0; +} + void serial_realize_core(SerialState *s, Error **errp) { if (!qemu_chr_fe_backend_connected(&s->chr)) { @@ -904,7 +932,7 @@ void serial_realize_core(SerialState *s, Error **errp) qemu_register_reset(serial_reset, s); qemu_chr_fe_set_handlers(&s->chr, serial_can_receive1, serial_receive1, - serial_event, NULL, s, NULL, true); + serial_event, serial_be_change, s, NULL, true); fifo8_create(&s->recv_fifo, UART_FIFO_LENGTH); fifo8_create(&s->xmit_fifo, UART_FIFO_LENGTH); serial_reset(s); -- 2.11.0