Adding upstream version 1:7.2+dfsg.upstream/1%7.2+dfsgupstream

Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>

1 files changed, 309 insertions, 0 deletions

diff --git a/hw/char/virtio-console.c b/hw/char/virtio-console.c
new file mode 100644
index 00000000..dd5a02e3
--- /dev/null
+++ b/hw/char/virtio-console.c
@@ -0,0 +1,309 @@
+/*
+ * Virtio Console and Generic Serial Port Devices
+ *
+ * Copyright Red Hat, Inc. 2009, 2010
+ *
+ * Authors:
+ *  Amit Shah <amit.shah@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "chardev/char-fe.h"
+#include "qemu/error-report.h"
+#include "qemu/module.h"
+#include "trace.h"
+#include "hw/qdev-properties.h"
+#include "hw/qdev-properties-system.h"
+#include "hw/virtio/virtio-serial.h"
+#include "qapi/error.h"
+#include "qapi/qapi-events-char.h"
+#include "qom/object.h"
+
+#define TYPE_VIRTIO_CONSOLE_SERIAL_PORT "virtserialport"
+typedef struct VirtConsole VirtConsole;
+DECLARE_INSTANCE_CHECKER(VirtConsole, VIRTIO_CONSOLE,
+                         TYPE_VIRTIO_CONSOLE_SERIAL_PORT)
+
+struct VirtConsole {
+    VirtIOSerialPort parent_obj;
+
+    CharBackend chr;
+    guint watch;
+};
+
+/*
+ * Callback function that's called from chardevs when backend becomes
+ * writable.
+ */
+static gboolean chr_write_unblocked(void *do_not_use, GIOCondition cond,
+                                    void *opaque)
+{
+    VirtConsole *vcon = opaque;
+
+    vcon->watch = 0;
+    virtio_serial_throttle_port(VIRTIO_SERIAL_PORT(vcon), 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, ssize_t len)
+{
+    VirtConsole *vcon = VIRTIO_CONSOLE(port);
+    ssize_t ret;
+
+    if (!qemu_chr_fe_backend_connected(&vcon->chr)) {
+        /* If there's no backend, we can just say we consumed all data. */
+        return len;
+    }
+
+    ret = qemu_chr_fe_write(&vcon->chr, buf, len);
+    trace_virtio_console_flush_buf(port->id, len, ret);
+
+    if (ret < len) {
+        VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
+
+        /*
+         * Ideally we'd get a better error code than just -1, but
+         * that's what the chardev interface gives us right now.  If
+         * we had a finer-grained message, like -EPIPE, we could close
+         * this connection.
+         */
+        if (ret < 0)
+            ret = 0;
+
+        /* XXX we should be queuing data to send later for the
+         * console devices too rather than silently dropping
+         * console data on EAGAIN. The Linux virtio-console
+         * hvc driver though does sends with spinlocks held,
+         * so if we enable throttling that'll stall the entire
+         * guest kernel, not merely the process writing to the
+         * console.
+         *
+         * While we could queue data for later write without
+         * enabling throttling, this would result in the guest
+         * being able to trigger arbitrary memory usage in QEMU
+         * buffering data for later writes.
+         *
+         * So fixing this problem likely requires fixing the
+         * Linux virtio-console hvc driver to not hold spinlocks
+         * while writing, and instead merely block the process
+         * that's writing. QEMU would then need some way to detect
+         * if the guest had the fixed driver too, before we can
+         * use throttling on host side.
+         */
+        if (!k->is_console) {
+            virtio_serial_throttle_port(port, true);
+            if (!vcon->watch) {
+                vcon->watch = qemu_chr_fe_add_watch(&vcon->chr,
+                                                    G_IO_OUT|G_IO_HUP,
+                                                    chr_write_unblocked, vcon);
+            }
+        }
+    }
+    return ret;
+}
+
+/* Callback function that's called when the guest opens/closes the port */
+static void set_guest_connected(VirtIOSerialPort *port, int guest_connected)
+{
+    VirtConsole *vcon = VIRTIO_CONSOLE(port);
+    DeviceState *dev = DEVICE(port);
+    VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
+
+    if (!k->is_console) {
+        qemu_chr_fe_set_open(&vcon->chr, guest_connected);
+    }
+
+    if (dev->id) {
+        qapi_event_send_vserport_change(dev->id, guest_connected);
+    }
+}
+
+static void guest_writable(VirtIOSerialPort *port)
+{
+    VirtConsole *vcon = VIRTIO_CONSOLE(port);
+
+    qemu_chr_fe_accept_input(&vcon->chr);
+}
+
+/* Readiness of the guest to accept data on a port */
+static int chr_can_read(void *opaque)
+{
+    VirtConsole *vcon = opaque;
+
+    return virtio_serial_guest_ready(VIRTIO_SERIAL_PORT(vcon));
+}
+
+/* Send data from a char device over to the guest */
+static void chr_read(void *opaque, const uint8_t *buf, int size)
+{
+    VirtConsole *vcon = opaque;
+    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon);
+
+    trace_virtio_console_chr_read(port->id, size);
+    virtio_serial_write(port, buf, size);
+}
+
+static void chr_event(void *opaque, QEMUChrEvent event)
+{
+    VirtConsole *vcon = opaque;
+    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon);
+
+    trace_virtio_console_chr_event(port->id, event);
+    switch (event) {
+    case CHR_EVENT_OPENED:
+        virtio_serial_open(port);
+        break;
+    case CHR_EVENT_CLOSED:
+        if (vcon->watch) {
+            g_source_remove(vcon->watch);
+            vcon->watch = 0;
+        }
+        virtio_serial_close(port);
+        break;
+    case CHR_EVENT_BREAK:
+    case CHR_EVENT_MUX_IN:
+    case CHR_EVENT_MUX_OUT:
+        /* Ignore */
+        break;
+    }
+}
+
+static int chr_be_change(void *opaque)
+{
+    VirtConsole *vcon = opaque;
+    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon);
+    VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
+
+    if (k->is_console) {
+        qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
+                                 NULL, chr_be_change, vcon, NULL, true);
+    } else {
+        qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
+                                 chr_event, chr_be_change, vcon, NULL, false);
+    }
+
+    if (vcon->watch) {
+        g_source_remove(vcon->watch);
+        vcon->watch = qemu_chr_fe_add_watch(&vcon->chr,
+                                            G_IO_OUT | G_IO_HUP,
+                                            chr_write_unblocked, vcon);
+    }
+
+    return 0;
+}
+
+static void virtconsole_enable_backend(VirtIOSerialPort *port, bool enable)
+{
+    VirtConsole *vcon = VIRTIO_CONSOLE(port);
+
+    if (!qemu_chr_fe_backend_connected(&vcon->chr)) {
+        return;
+    }
+
+    if (enable) {
+        VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
+
+        qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
+                                 k->is_console ? NULL : chr_event,
+                                 chr_be_change, vcon, NULL, false);
+    } else {
+        qemu_chr_fe_set_handlers(&vcon->chr, NULL, NULL, NULL,
+                                 NULL, NULL, NULL, false);
+    }
+}
+
+static void virtconsole_realize(DeviceState *dev, Error **errp)
+{
+    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
+    VirtConsole *vcon = VIRTIO_CONSOLE(dev);
+    VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
+
+    if (port->id == 0 && !k->is_console) {
+        error_setg(errp, "Port number 0 on virtio-serial devices reserved "
+                   "for virtconsole devices for backward compatibility.");
+        return;
+    }
+
+    if (qemu_chr_fe_backend_connected(&vcon->chr)) {
+        /*
+         * For consoles we don't block guest data transfer just
+         * because nothing is connected - we'll just let it go
+         * whetherever the chardev wants - /dev/null probably.
+         *
+         * For serial ports we need 100% reliable data transfer
+         * so we use the opened/closed signals from chardev to
+         * trigger open/close of the device
+         */
+        if (k->is_console) {
+            qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
+                                     NULL, chr_be_change,
+                                     vcon, NULL, true);
+            virtio_serial_open(port);
+        } else {
+            qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
+                                     chr_event, chr_be_change,
+                                     vcon, NULL, false);
+        }
+    }
+}
+
+static void virtconsole_unrealize(DeviceState *dev)
+{
+    VirtConsole *vcon = VIRTIO_CONSOLE(dev);
+
+    if (vcon->watch) {
+        g_source_remove(vcon->watch);
+    }
+}
+
+static void virtconsole_class_init(ObjectClass *klass, void *data)
+{
+    VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass);
+
+    k->is_console = true;
+}
+
+static const TypeInfo virtconsole_info = {
+    .name          = "virtconsole",
+    .parent        = TYPE_VIRTIO_CONSOLE_SERIAL_PORT,
+    .class_init    = virtconsole_class_init,
+};
+
+static Property virtserialport_properties[] = {
+    DEFINE_PROP_CHR("chardev", VirtConsole, chr),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void virtserialport_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass);
+
+    k->realize = virtconsole_realize;
+    k->unrealize = virtconsole_unrealize;
+    k->have_data = flush_buf;
+    k->set_guest_connected = set_guest_connected;
+    k->enable_backend = virtconsole_enable_backend;
+    k->guest_writable = guest_writable;
+    device_class_set_props(dc, virtserialport_properties);
+}
+
+static const TypeInfo virtserialport_info = {
+    .name          = TYPE_VIRTIO_CONSOLE_SERIAL_PORT,
+    .parent        = TYPE_VIRTIO_SERIAL_PORT,
+    .instance_size = sizeof(VirtConsole),
+    .class_init    = virtserialport_class_init,
+};
+
+static void virtconsole_register_types(void)
+{
+    type_register_static(&virtserialport_info);
+    type_register_static(&virtconsole_info);
+}
+
+type_init(virtconsole_register_types)