From 9c6b84014b3650e478494d3c19b7461b947b3b14 Mon Sep 17 00:00:00 2001
From: Gal Hammer <ghammer@redhat.com>
Date: Sun, 16 Mar 2014 09:57:09 +0100
Subject: [PATCH 01/31] char: restore read callback on a reattached (hotplug) chardev

RH-Author: Gal Hammer <ghammer@redhat.com>
Message-id: <1394963829-5384-1-git-send-email-ghammer@redhat.com>
Patchwork-id: 58105
O-Subject: [RHEL-7.0 qemu-kvm PATCH] char: restore read callback on a reattached (hotplug) chardev
Bugzilla: 1038914
RH-Acked-by: Gerd Hoffmann <kraxel@redhat.com>
RH-Acked-by: Amit Shah <amit.shah@redhat.com>
RH-Acked-by: Amos Kong <akong@redhat.com>

Bugzilla: 1027181
Brew: https://brewweb.devel.redhat.com/taskinfo?taskID=7207613
Upstream: commit ac1b84dd1e020648db82a99260891aa982d1142c

Fix a bug that was introduced in commit 386a5a1e. A removal of a device
set the chr handlers to NULL. However when the device is plugged back,
its read callback is not restored so data can't be transferred from the
host to the guest (e.g. via the virtio-serial port).

https://bugzilla.redhat.com/show_bug.cgi?id=1027181

Signed-off-by: Gal Hammer <ghammer@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 qemu-char.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 qemu-char.c |   17 +++++++++++++++--
 1 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 983f686..930f3d4 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -215,7 +215,7 @@ void qemu_chr_add_handlers(CharDriverState *s,
     s->chr_read = fd_read;
     s->chr_event = fd_event;
     s->handler_opaque = opaque;
-    if (s->chr_update_read_handler)
+    if (fe_open && s->chr_update_read_handler)
         s->chr_update_read_handler(s);
 
     if (!s->explicit_fe_open) {
@@ -1140,13 +1140,14 @@ static void pty_chr_state(CharDriverState *chr, int connected)
         if (!s->connected) {
             s->connected = 1;
             qemu_chr_be_generic_open(chr);
+        }
+        if (!chr->fd_in_tag) {
             chr->fd_in_tag = io_add_watch_poll(s->fd, pty_chr_read_poll,
                                                pty_chr_read, chr);
         }
     }
 }
 
-
 static void pty_chr_close(struct CharDriverState *chr)
 {
     PtyCharDriver *s = chr->opaque;
@@ -2514,6 +2515,17 @@ static void tcp_chr_connect(void *opaque)
     qemu_chr_be_generic_open(chr);
 }
 
+static void tcp_chr_update_read_handler(CharDriverState *chr)
+{
+    TCPCharDriver *s = chr->opaque;
+
+    remove_fd_in_watch(chr);
+    if (s->chan) {
+        chr->fd_in_tag = io_add_watch_poll(s->chan, tcp_chr_read_poll,
+                                           tcp_chr_read, chr);
+    }
+}
+
 #define IACSET(x,a,b,c) x[0] = a; x[1] = b; x[2] = c;
 static void tcp_chr_telnet_init(int fd)
 {
@@ -2669,6 +2681,7 @@ static CharDriverState *qemu_chr_open_socket_fd(int fd, bool do_nodelay,
     chr->get_msgfd = tcp_get_msgfd;
     chr->chr_add_client = tcp_chr_add_client;
     chr->chr_add_watch = tcp_chr_add_watch;
+    chr->chr_update_read_handler = tcp_chr_update_read_handler;
     /* be isn't opened until we get a connection */
     chr->explicit_be_open = true;
 
-- 
1.7.1