virtio: console: add flow control

[qemu.git] / hw / virtio-console.c

diff --git a/hw/virtio-console.c b/hw/virtio-console.c
index 46072a086fd6153e7546a565524940c02739a1b1..b3ee074a87648f743b3c4f1823d4e78d9b2711f4 100644 (file)
--- a/hw/virtio-console.c
+++ b/hw/virtio-console.c
@@ -20,6 +20,18 @@ typedef struct VirtConsole {
     CharDriverState *chr;
 } VirtConsole;
 
+/*
+ * Callback function that's called from chardevs when backend becomes
+ * writable.
+ */
+static gboolean chr_write_unblocked(GIOChannel *chan, GIOCondition cond,
+                                    void *opaque)
+{
+    VirtConsole *vcon = opaque;
+
+    virtio_serial_throttle_port(&vcon->port, false);
+    return FALSE;
+}
 
 /* Callback function that's called when the guest sends us data */
 static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
@@ -48,6 +60,7 @@ static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
          * do_flush_queued_data().
          */
         ret = 0;
+        qemu_chr_fe_add_watch(vcon->chr, G_IO_OUT, chr_write_unblocked, vcon);
     }
     return ret;
 }