Re: [Qemu-devel] [RFC PATCH V8 02/15] virtio-bus : Introduce virtio-bus

["KONRAD Frédéric" <fred.konrad@greensocs.com>]

On 02/01/2013 15:12, Anthony Liguori wrote:
> fred.konrad@greensocs.com writes:
>
>> From: KONRAD Frederic <fred.konrad@greensocs.com>
>>
>> Introduce virtio-bus. Refactored transport device will create a bus which
>> extends virtio-bus.
>>
>> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
>> ---
>>   hw/Makefile.objs |   1 +
>>   hw/virtio-bus.c  | 169 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   hw/virtio-bus.h  |  98 ++++++++++++++++++++++++++++++++
>>   3 files changed, 268 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 d581d8d..6fa4de4 100644
>> --- a/hw/Makefile.objs
>> +++ b/hw/Makefile.objs
>> @@ -3,6 +3,7 @@ common-obj-y += loader.o
>>   common-obj-$(CONFIG_VIRTIO) += virtio-console.o
>>   common-obj-$(CONFIG_VIRTIO) += virtio-rng.o
>>   common-obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o
>> +common-obj-$(CONFIG_VIRTIO) += virtio-bus.o
>>   common-obj-y += fw_cfg.o
>>   common-obj-$(CONFIG_PCI) += pci.o pci_bridge.o pci_bridge_dev.o
>>   common-obj-$(CONFIG_PCI) += msix.o msi.o
>> diff --git a/hw/virtio-bus.c b/hw/virtio-bus.c
>> new file mode 100644
>> index 0000000..7a3d06e
>> --- /dev/null
>> +++ b/hw/virtio-bus.c
>> @@ -0,0 +1,169 @@
>> +/*
>> + * VirtioBus
>> + *
>> + *  Copyright (C) 2012 : GreenSocs Ltd
>> + *      http://www.greensocs.com/ , email: info@greensocs.com
>> + *
>> + *  Developed by :
>> + *  Frederic Konrad   <fred.konrad@greensocs.com>
>> + *
>> + * 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 */
>> +
>> +#ifdef DEBUG_VIRTIO_BUS
>> +#define DPRINTF(fmt, ...) \
>> +do { printf("virtio_bus: " fmt , ## __VA_ARGS__); } while (0)
>> +#else
>> +#define DPRINTF(fmt, ...) do { } while (0)
>> +#endif
>> +
>> +/* Plug the VirtIODevice */
>> +int virtio_bus_plug_device(VirtIODevice *vdev)
>> +{
>> +    DeviceState *qdev = DEVICE(vdev);
>> +    BusState *qbus = BUS(qdev_get_parent_bus(qdev));
>> +    VirtioBusState *bus = VIRTIO_BUS(qbus);
>> +    VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
>> +    DPRINTF("%s : plug device.\n", qbus->name);
>> +
>> +    bus->vdev = vdev;
>> +
>> +    if (klass->device_plugged != NULL) {
>> +        klass->device_plugged(qbus->parent);
>> +    }
>> +
>> +    /*
>> +     * The lines below will disappear when we drop VirtIOBindings, at the end
>> +     * of the serie.
> s/serie/series/g
>
>> +     */
>> +    bus->bindings.notify = klass->notify;
>> +    bus->bindings.save_config = klass->save_config;
>> +    bus->bindings.save_queue = klass->save_queue;
>> +    bus->bindings.load_config = klass->load_config;
>> +    bus->bindings.load_queue = klass->load_queue;
>> +    bus->bindings.load_done = klass->load_done;
>> +    bus->bindings.get_features = klass->get_features;
>> +    bus->bindings.query_guest_notifiers = klass->query_guest_notifiers;
>> +    bus->bindings.set_guest_notifiers = klass->set_guest_notifiers;
>> +    bus->bindings.set_host_notifier = klass->set_host_notifier;
>> +    bus->bindings.vmstate_change = klass->vmstate_change;
>> +    virtio_bind_device(bus->vdev, &(bus->bindings), qbus->parent);
>> +    /*
>> +     */
> No need for empty comment or the parens around bus->bindings.
>
>> +
>> +    return 0;
>> +}
>> +
>> +/* Reset the virtio_bus */
>> +void virtio_bus_reset(VirtioBusState *bus)
>> +{
>> +    DPRINTF("%s : reset device.\n", qbus->name);
>> +    if (bus->vdev != NULL) {
>> +        virtio_reset(bus->vdev);
>> +    }
>> +}
>> +
>> +/* Destroy the VirtIODevice */
>> +void virtio_bus_destroy_device(VirtioBusState *bus)
>> +{
>> +    DeviceState *qdev;
>> +    BusState *qbus = BUS(bus);
>> +    VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
>> +    DPRINTF("%s : remove device.\n", qbus->name);
>> +
>> +    if (bus->vdev != NULL) {
>> +        if (klass->device_unplug != NULL) {
>> +            klass->device_unplug(qbus->parent);
>> +        }
>> +        qdev = DEVICE(bus->vdev);
>> +        qdev_free(qdev);
>> +        bus->vdev = NULL;
>> +    }
>> +}
>> +
>> +/* Get the device id of the plugged device. */
>> +uint16_t get_virtio_device_id(VirtioBusState *bus)
>> +{
>> +    assert(bus->vdev != NULL);
>> +    return bus->vdev->device_id;
>> +}
>> +
>> +/* Get the nvectors field of the plugged device. */
>> +int get_virtio_device_nvectors(VirtioBusState *bus)
>> +{
>> +    assert(bus->vdev != NULL);
>> +    return bus->vdev->nvectors;
>> +}
>> +
>> +/* Set the nvectors field of the plugged device. */
>> +void set_virtio_device_nvectors(VirtioBusState *bus, int nvectors)
>> +{
>> +    assert(bus->vdev != NULL);
>> +    bus->vdev->nvectors = nvectors;
>> +}
>> +
>> +/* Get the config_len field of the plugged device. */
>> +size_t get_virtio_device_config_len(VirtioBusState *bus)
>> +{
>> +    assert(bus->vdev != NULL);
>> +    return bus->vdev->config_len;
>> +}
>> +
>> +/* Get the features of the plugged device. */
>> +uint32_t get_virtio_device_features(VirtioBusState *bus,
>> +                                    uint32_t requested_features)
>> +{
>> +    VirtioDeviceClass *k;
>> +    assert(bus->vdev != NULL);
>> +    k = VIRTIO_DEVICE_GET_CLASS(bus->vdev);
>> +    assert(k->get_features != NULL);
>> +    return k->get_features(bus->vdev, requested_features);
>> +}
>> +
>> +/* Get the bad features of the plugged device. */
>> +uint32_t get_virtio_device_bad_features(VirtioBusState *bus)
>> +{
>> +    VirtioDeviceClass *k;
>> +    assert(bus->vdev != NULL);
>> +    k = VIRTIO_DEVICE_GET_CLASS(bus->vdev);
>> +    if (k->bad_features != NULL) {
>> +        return k->bad_features(bus->vdev);
>> +    } else {
>> +        return 0;
>> +    }
>> +}
> These functions should be in the form:
>
> virtio_device_get_bad_features()
>
> With 'virtio_device_' as the common prefix.
>
>> +static const TypeInfo virtio_bus_info = {
>> +    .name = TYPE_VIRTIO_BUS,
>> +    .parent = TYPE_BUS,
>> +    .instance_size = sizeof(VirtioBusState),
>> +    .abstract = true,
>> +    .class_size = sizeof(VirtioBusClass),
>> +};
>> +
>> +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..a2e2012
>> --- /dev/null
>> +++ b/hw/virtio-bus.h
>> @@ -0,0 +1,98 @@
>> +/*
>> + * VirtioBus
>> + *
>> + *  Copyright (C) 2012 : GreenSocs Ltd
>> + *      http://www.greensocs.com/ , email: info@greensocs.com
>> + *
>> + *  Developed by :
>> + *  Frederic Konrad   <fred.konrad@greensocs.com>
>> + *
>> + * 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_GET_CLASS(obj) \
>> +        OBJECT_GET_CLASS(VirtioBusClass, obj, TYPE_VIRTIO_BUS)
>> +#define VIRTIO_BUS_CLASS(klass) \
>> +        OBJECT_CLASS_CHECK(VirtioBusClass, klass, TYPE_VIRTIO_BUS)
>> +#define VIRTIO_BUS(obj) OBJECT_CHECK(VirtioBusState, (obj), TYPE_VIRTIO_BUS)
>> +
>> +typedef struct VirtioBusState VirtioBusState;
>> +
>> +typedef struct VirtioBusClass {
>> +    /* This is what a VirtioBus must implement */
>> +    BusClass parent;
>> +    void (*notify)(void *opaque, uint16_t vector);
>> +    void (*save_config)(void *opaque, QEMUFile *f);
>> +    void (*save_queue)(void *opaque, int n, QEMUFile *f);
>> +    int (*load_config)(void *opaque, QEMUFile *f);
>> +    int (*load_queue)(void *opaque, int n, QEMUFile *f);
>> +    int (*load_done)(void *opaque, QEMUFile *f);
>> +    unsigned (*get_features)(void *opaque);
>> +    bool (*query_guest_notifiers)(void *opaque);
>> +    int (*set_guest_notifiers)(void *opaque, bool assigned);
>> +    int (*set_host_notifier)(void *opaque, int n, bool assigned);
>> +    void (*vmstate_change)(void *opaque, bool running);
>> +    /*
>> +     * transport independent init function.
>> +     * This is called by virtio-bus just after the device is plugged.
>> +     */
>> +    void (*device_plugged)(void *opaque);
>> +    /*
>> +     * transport independent exit function.
>> +     * This is called by virtio-bus just before the device is unplugged.
>> +     */
>> +    void (*device_unplug)(void *opaque);
> These should not take a 'void *' but rather a VirtIODevice.  You can
> just do a cast in the short term to handle the mismatch with
> VirtIOBindings.
Are you sure ?

Here the opaque argument is not pointing a VirtIODevice but a transport.

eg for virtio-pci :

static void virtio_pci_notify(void *opaque, uint16_t vector)
{
     VirtIOPCIProxy *proxy = opaque;
     if (msix_enabled(&proxy->pci_dev))
         msix_notify(&proxy->pci_dev, vector);
     else
         qemu_set_irq(proxy->pci_dev.irq[0], proxy->vdev->isr & 1);
}

>
> Regards,
>
> Anthony Liguori
>
>> +} VirtioBusClass;
>> +
>> +struct VirtioBusState {
>> +    BusState parent_obj;
>> +    /*
>> +     * Only one VirtIODevice can be plugged on the bus.
>> +     */
>> +    VirtIODevice *vdev;
>> +    /*
>> +     * This will be removed at the end of the serie.
>> +     */
>> +    VirtIOBindings bindings;
>> +    /*
>> +     */
>> +};
>> +
>> +int virtio_bus_plug_device(VirtIODevice *vdev);
>> +void virtio_bus_reset(VirtioBusState *bus);
>> +void virtio_bus_destroy_device(VirtioBusState *bus);
>> +/* Get the device id of the plugged device. */
>> +uint16_t get_virtio_device_id(VirtioBusState *bus);
>> +/* Get the nvectors field of the plugged device. */
>> +int get_virtio_device_nvectors(VirtioBusState *bus);
>> +/* Set the nvectors field of the plugged device. */
>> +void set_virtio_device_nvectors(VirtioBusState *bus, int nvectors);
>> +/* Get the config_len field of the plugged device. */
>> +size_t get_virtio_device_config_len(VirtioBusState *bus);
>> +/* Get the features of the plugged device. */
>> +uint32_t get_virtio_device_features(VirtioBusState *bus,
>> +                                    uint32_t requested_features);
>> +/* Get the bad features of the plugged device. */
>> +uint32_t get_virtio_device_bad_features(VirtioBusState *bus);
>> +
>> +#endif /* VIRTIO_BUS_H */
>> -- 
>> 1.7.11.7