aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorPaolo Bonzini <pbonzini@redhat.com>2016-06-14 14:46:51 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2016-06-29 14:03:47 +0200
commit9f34a35e0020b0b2b2e21c086a486d7dfd18df4f (patch)
tree71634306618e72cfa9bab75006c1fe03a07a73e9
parenta1df76da57aa8772a75e7c49f8e3829d07b4c46c (diff)
downloadqemu-9f34a35e0020b0b2b2e21c086a486d7dfd18df4f.zip
qemu-9f34a35e0020b0b2b2e21c086a486d7dfd18df4f.tar.gz
qemu-9f34a35e0020b0b2b2e21c086a486d7dfd18df4f.tar.bz2
serial: reinstate watch after migration
Otherwise, a serial port can get stuck if it is migrated while flow control is in effect. Tested-by: Bret Ketchum <bcketchum@gmail.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--hw/char/serial.c25
1 files changed, 23 insertions, 2 deletions
diff --git a/hw/char/serial.c b/hw/char/serial.c
index af39e8f..3442f47 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -644,8 +644,29 @@ static int serial_post_load(void *opaque, int version_id)
if (s->thr_ipending == -1) {
s->thr_ipending = ((s->iir & UART_IIR_ID) == UART_IIR_THRI);
}
- if (s->tsr_retry > MAX_XMIT_RETRY) {
- s->tsr_retry = MAX_XMIT_RETRY;
+
+ if (s->tsr_retry > 0) {
+ /* tsr_retry > 0 implies LSR.TEMT = 0 (transmitter not empty). */
+ if (s->lsr & UART_LSR_TEMT) {
+ error_report("inconsistent state in serial device "
+ "(tsr empty, tsr_retry=%d", s->tsr_retry);
+ return -1;
+ }
+
+ if (s->tsr_retry > MAX_XMIT_RETRY) {
+ s->tsr_retry = MAX_XMIT_RETRY;
+ }
+
+ assert(s->watch_tag == 0);
+ s->watch_tag = qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP,
+ serial_watch_cb, s);
+ } else {
+ /* tsr_retry == 0 implies LSR.TEMT = 1 (transmitter empty). */
+ if (!(s->lsr & UART_LSR_TEMT)) {
+ error_report("inconsistent state in serial device "
+ "(tsr not empty, tsr_retry=0");
+ return -1;
+ }
}
s->last_break_enable = (s->lcr >> 6) & 1;