[Qemu-devel] [RFC PATCH v2 1/3] virtio-bus : Introduce VirtioBus.

[fred . konrad]

From: KONRAD Frederic <address@hidden>

This patch create a new VirtioBus, which can be added to Virtio transports like
virtio-pci, virtio-mmio,...

One VirtIODevice can be connected to this device, like virtio-blk in the 3rd
patch.

The VirtioBus shares through a VirtioBusInfo structure :

    * two callbacks with the transport : init_cb and exit_cb, which must be
      called by the VirtIODevice, after the initialization and before the
      destruction, to put the right PCI IDs and/or stop the event fd.

    * a VirtIOBindings structure.

Signed-off-by: KONRAD Frederic <address@hidden>
---
 hw/Makefile.objs |   1 +
 hw/virtio-bus.c  | 148 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/virtio-bus.h  |  58 ++++++++++++++++++++++
 3 files changed, 207 insertions(+)
 create mode 100644 hw/virtio-bus.c
 create mode 100644 hw/virtio-bus.h

diff --git a/hw/Makefile.objs b/hw/Makefile.objs
index ea46f81..bd14d1b 100644
--- a/hw/Makefile.objs
+++ b/hw/Makefile.objs
@@ -2,6 +2,7 @@ common-obj-y = usb/ ide/
 common-obj-y += loader.o
 common-obj-$(CONFIG_VIRTIO) += virtio-console.o
 common-obj-$(CONFIG_VIRTIO) += virtio-rng.o
+common-obj-$(CONFIG_VIRTIO) += virtio-bus.o
 common-obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o
 common-obj-y += fw_cfg.o
 common-obj-$(CONFIG_PCI) += pci.o pci_bridge.o pci_bridge_dev.o
diff --git a/hw/virtio-bus.c b/hw/virtio-bus.c
new file mode 100644
index 0000000..991b6f5
--- /dev/null
+++ b/hw/virtio-bus.c
@@ -0,0 +1,148 @@
+/*
+ * VirtioBus
+ *
+ *  Copyright (C) 2012 : GreenSocs Ltd
+ *      http://www.greensocs.com/ , email: address@hidden
+ *
+ *  Developed by :
+ *  Frederic Konrad   <address@hidden>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "hw.h"
+#include "qemu-error.h"
+#include "qdev.h"
+#include "virtio-bus.h"
+#include "virtio.h"
+
+#define DEBUG_VIRTIO_BUS 1
+
+#define DPRINTF(fmt, ...) if (DEBUG_VIRTIO_BUS) {                        \
+                            printf("virtio_bus: " fmt , ## __VA_ARGS__); \
+                          }
+
+static void virtio_bus_init_cb(VirtioBus *bus);
+static int virtio_bus_reset(BusState *qbus);
+
+static void virtio_bus_class_init(ObjectClass *klass, void *data)
+{
+    BusClass *k = BUS_CLASS(klass);
+    k->reset = virtio_bus_reset;
+}
+
+static TypeInfo virtio_bus_info = {
+    .name = TYPE_VIRTIO_BUS,
+    .parent = TYPE_BUS,
+    .instance_size = sizeof(VirtioBus),
+    .class_init = virtio_bus_class_init,
+};
+
+/* Reset the bus */
+static int virtio_bus_reset(BusState *qbus)
+{
+    VirtioBus *bus = VIRTIO_BUS(qbus);
+    if (bus->bus_in_use) {
+        virtio_reset(bus->vdev);
+    }
+    return 1;
+}
+
+/* Plug the VirtIODevice */
+int virtio_bus_plug_device(VirtioBus *bus, VirtIODevice *vdev)
+{
+    BusState *qbus = BUS(bus);
+    /*
+     * This is a problem, when bus= option is not set, the last created
+     * virtio-bus is used. So it give the following error.
+     */
+    DPRINTF("plug device into %s.\n", qbus->name);
+    if (bus->bus_in_use) {
+        error_report("%s in use.\n", qbus->name);
+        return -1;
+    }
+    bus->bus_in_use = true;
+
+    /* keep the VirtIODevice in the VirtioBus. */
+    bus->vdev = vdev;
+
+    /* call the "transport" callback. */
+    virtio_bus_init_cb(bus);
+    return 0;
+}
+
+/* Create a virtio bus.  */
+VirtioBus *virtio_bus_new(DeviceState *host, const VirtioBusInfo *info)
+{
+    /*
+     * This is needed, as we want to have different names for each virtio-bus.
+     * If we don't do that, we can't add more than one VirtIODevice.
+     */
+    static int next_virtio_bus;
+    char *bus_name = g_strdup_printf("virtio-bus.%d", next_virtio_bus++);
+
+    BusState *qbus = qbus_create(TYPE_VIRTIO_BUS, host, bus_name);
+    VirtioBus *bus = VIRTIO_BUS(qbus);
+    bus->info = info;
+    qbus->allow_hotplug = 0;
+    bus->bus_in_use = false;
+    DPRINTF("%s bus created\n", bus_name);
+    return bus;
+}
+
+/* Bind the VirtIODevice to the VirtioBus. */
+void virtio_bus_bind_device(VirtioBus *bus)
+{
+    BusState *qbus = BUS(bus);
+    assert(bus != NULL);
+    assert(bus->vdev != NULL);
+    virtio_bind_device(bus->vdev, &(bus->info->virtio_bindings), qbus->parent);
+}
+
+/*
+ * Transport independent init.
+ * This must be called after VirtIODevice initialization.
+ */
+static void virtio_bus_init_cb(VirtioBus *bus)
+{
+    BusState *qbus = BUS(bus);
+    assert(bus->info->init_cb != NULL);
+    bus->info->init_cb(qbus->parent);
+}
+
+/*
+ * Transport independent exit.
+ * This must be called by the VirtIODevice before destroying it.
+ */
+void virtio_bus_exit_cb(VirtioBus *bus)
+{
+    BusState *qbus = BUS(bus);
+    assert(bus->info->exit_cb != NULL);
+    bus->info->exit_cb(qbus->parent);
+    bus->bus_in_use = false;
+}
+
+/* Return the virtio device id of the plugged device. */
+uint16_t get_virtio_device_id(VirtioBus *bus)
+{
+    return bus->vdev->device_id;
+}
+
+static void virtio_register_types(void)
+{
+    type_register_static(&virtio_bus_info);
+}
+
+type_init(virtio_register_types)
diff --git a/hw/virtio-bus.h b/hw/virtio-bus.h
new file mode 100644
index 0000000..31aad53
--- /dev/null
+++ b/hw/virtio-bus.h
@@ -0,0 +1,58 @@
+/*
+ * VirtioBus
+ *
+ *  Copyright (C) 2012 : GreenSocs Ltd
+ *      http://www.greensocs.com/ , email: address@hidden
+ *
+ *  Developed by :
+ *  Frederic Konrad   <address@hidden>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef VIRTIO_BUS_H
+#define VIRTIO_BUS_H
+
+#include "qdev.h"
+#include "sysemu.h"
+#include "virtio.h"
+
+#define TYPE_VIRTIO_BUS "virtio-bus"
+#define VIRTIO_BUS(obj) OBJECT_CHECK(VirtioBus, (obj), TYPE_VIRTIO_BUS)
+
+typedef struct VirtioBus VirtioBus;
+typedef struct VirtioBusInfo VirtioBusInfo;
+
+struct VirtioBusInfo {
+    void (*init_cb)(DeviceState *dev);
+    void (*exit_cb)(DeviceState *dev);
+    VirtIOBindings virtio_bindings;
+};
+
+struct VirtioBus {
+    BusState qbus;
+    bool bus_in_use;
+    /* Only one VirtIODevice can be plugged on the bus. */
+    VirtIODevice *vdev;
+    const VirtioBusInfo *info;
+};
+
+VirtioBus *virtio_bus_new(DeviceState *host, const VirtioBusInfo *info);
+void virtio_bus_bind_device(VirtioBus *bus);
+int virtio_bus_plug_device(VirtioBus *bus, VirtIODevice *vdev);
+void virtio_bus_exit_cb(VirtioBus *bus);
+uint16_t get_virtio_device_id(VirtioBus *bus);
+
+#endif /* VIRTIO_BUS_H */
-- 
1.7.11.7