diff options
| -rw-r--r-- | hw/char/cadence_uart.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c index c856fc30b2..844542fd5a 100644 --- a/hw/char/cadence_uart.c +++ b/hw/char/cadence_uart.c @@ -288,8 +288,11 @@ static gboolean cadence_uart_xmit(GIOChannel *chan, GIOCondition cond, } ret = qemu_chr_fe_write(s->chr, s->tx_fifo, s->tx_count); - s->tx_count -= ret; - memmove(s->tx_fifo, s->tx_fifo + ret, s->tx_count); + + if (ret >= 0) { + s->tx_count -= ret; + memmove(s->tx_fifo, s->tx_fifo + ret, s->tx_count); + } if (s->tx_count) { int r = qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP, |