From: Dr. David Alan Gilbert <dgilbert@redhat.com>
Date: Mon, 26 Feb 2018 13:04:52 +0000 (+0000)
Subject: serial: Open non-block
X-Git-Tag: v3.0.0-rc0~34^2~3
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=76b004d10da09bb77a4343edf7b98b2d662fb4f2;p=thirdparty%2Fqemu.git

serial: Open non-block

On a real serial device, the open can block if the handshake
lines are in a particular state.  If a QEMU is passing the serial
device to the guest, the QEMU startup is blocked opening the device
(with a symptom seen as a timeout from libvirt).

Open the serial port with O_NONBLOCK.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/chardev/char-serial.c b/chardev/char-serial.c
index ae548d28da9..3299b468530 100644
--- a/chardev/char-serial.c
+++ b/chardev/char-serial.c
@@ -265,7 +265,8 @@ static void qmp_chardev_open_serial(Chardev *chr,
     ChardevHostdev *serial = backend->u.serial.data;
     int fd;
 
-    fd = qmp_chardev_open_file_source(serial->device, O_RDWR, errp);
+    fd = qmp_chardev_open_file_source(serial->device, O_RDWR | O_NONBLOCK,
+                                      errp);
     if (fd < 0) {
         return;
     }