2 files changed, 54 insertions, 7 deletions

diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
index dbbc167425..a5736cbc07 100644
--- a/hw/char/cadence_uart.c
+++ b/hw/char/cadence_uart.c
@@ -175,8 +175,10 @@ static void uart_send_breaks(UartState *s)
 {
     int break_enabled = 1;
 
-    qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
-                               &break_enabled);
+    if (s->chr) {
+        qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
+                                   &break_enabled);
+    }
 }
 
 static void uart_parameters_setup(UartState *s)
@@ -227,7 +229,9 @@ static void uart_parameters_setup(UartState *s)
 
     packet_size += ssp.data_bits + ssp.stop_bits;
     s->char_tx_time = (get_ticks_per_sec() / ssp.speed) * packet_size;
-    qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_PARAMS, &ssp);
+    if (s->chr) {
+        qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_PARAMS, &ssp);
+    }
 }
 
 static int uart_can_receive(void *opaque)
@@ -295,6 +299,7 @@ static gboolean cadence_uart_xmit(GIOChannel *chan, GIOCondition cond,
     /* instant drain the fifo when there's no back-end */
     if (!s->chr) {
         s->tx_count = 0;
+        return FALSE;
     }
 
     if (!s->tx_count) {
@@ -375,7 +380,9 @@ static void uart_read_rx_fifo(UartState *s, uint32_t *c)
         *c = s->rx_fifo[rx_rpos];
         s->rx_count--;
 
-        qemu_chr_accept_input(s->chr);
+        if (s->chr) {
+            qemu_chr_accept_input(s->chr);
+        }
     } else {
         *c = 0;
     }
diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
index 07bebc03ac..3931085983 100644
--- a/hw/char/virtio-serial-bus.c
+++ b/hw/char/virtio-serial-bus.c
@@ -26,6 +26,10 @@
 #include "hw/virtio/virtio-serial.h"
 #include "hw/virtio/virtio-access.h"
 
+struct VirtIOSerialDevices {
+    QLIST_HEAD(, VirtIOSerial) devices;
+} vserdevices;
+
 static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
 {
     VirtIOSerialPort *port;
@@ -52,6 +56,22 @@ static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
     return NULL;
 }
 
+static VirtIOSerialPort *find_port_by_name(char *name)
+{
+    VirtIOSerial *vser;
+
+    QLIST_FOREACH(vser, &vserdevices.devices, next) {
+        VirtIOSerialPort *port;
+
+        QTAILQ_FOREACH(port, &vser->ports, next) {
+            if (!strcmp(port->name, name)) {
+                return port;
+            }
+        }
+    }
+    return NULL;
+}
+
 static bool use_multiport(VirtIOSerial *vser)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(vser);
@@ -797,10 +817,18 @@ static void add_port(VirtIOSerial *vser, uint32_t port_id)
 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 {
     VirtIOSerialPort *port;
-    unsigned int i;
 
-    i = port_id / 32;
-    vser->ports_map[i] &= ~(1U << (port_id % 32));
+    /*
+     * Don't mark port 0 removed -- we explicitly reserve it for
+     * backward compat with older guests, ensure a virtconsole device
+     * unplug retains the reservation.
+     */
+    if (port_id) {
+        unsigned int i;
+
+        i = port_id / 32;
+        vser->ports_map[i] &= ~(1U << (port_id % 32));
+    }
 
     port = find_port_by_id(vser, port_id);
     /*
@@ -843,6 +871,12 @@ static void virtser_port_device_realize(DeviceState *dev, Error **errp)
         return;
     }
 
+    if (find_port_by_name(port->name)) {
+        error_setg(errp, "virtio-serial-bus: A port already exists by name %s",
+                   port->name);
+        return;
+    }
+
     if (port->id == VIRTIO_CONSOLE_BAD_ID) {
         if (plugging_port0) {
             port->id = 0;
@@ -975,6 +1009,8 @@ static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
      */
     register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
                     virtio_serial_load, vser);
+
+    QLIST_INSERT_HEAD(&vserdevices.devices, vser, next);
 }
 
 static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
@@ -1003,6 +1039,8 @@ static void virtio_serial_device_unrealize(DeviceState *dev, Error **errp)
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VirtIOSerial *vser = VIRTIO_SERIAL(dev);
 
+    QLIST_REMOVE(vser, next);
+
     unregister_savevm(dev, "virtio-console", vser);
 
     g_free(vser->ivqs);
@@ -1027,6 +1065,8 @@ static void virtio_serial_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 
+    QLIST_INIT(&vserdevices.devices);
+
     dc->props = virtio_serial_properties;
     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
     vdc->realize = virtio_serial_device_realize;