Re: [PATCH v2 12/13] hw/virtio: derive vhost-user-i2c from vhost-user-base

[Mark Cave-Ayland]

On 18/04/2023 17:21, Alex Bennée wrote:

> Now we can take advantage of the new base class and make
> vhost-user-i2c a much simpler boilerplate wrapper. Also as this
> doesn't require any target specific hacks we only need to build the
> stubs once.
>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>
> ---
> v2
>    - update to new inheritance scheme
>    - move build to common code
> ---
>   include/hw/virtio/vhost-user-i2c.h |  18 +-
>   hw/virtio/vhost-user-i2c.c         | 255 ++---------------------------
>   hw/virtio/meson.build              |   5 +-
>   3 files changed, 26 insertions(+), 252 deletions(-)
>
> diff --git a/include/hw/virtio/vhost-user-i2c.h 
> b/include/hw/virtio/vhost-user-i2c.h
> index 0f7acd40e3..47153782d1 100644
> --- a/include/hw/virtio/vhost-user-i2c.h
> +++ b/include/hw/virtio/vhost-user-i2c.h
> @@ -12,20 +12,18 @@
>   #include "hw/virtio/vhost.h"
>   #include "hw/virtio/vhost-user.h"
>   
> +#include "hw/virtio/virtio.h"
> +#include "hw/virtio/vhost.h"
> +#include "hw/virtio/vhost-user.h"
> +#include "hw/virtio/vhost-user-device.h"
> +
>   #define TYPE_VHOST_USER_I2C "vhost-user-i2c-device"
>   OBJECT_DECLARE_SIMPLE_TYPE(VHostUserI2C, VHOST_USER_I2C)
>   
>   struct VHostUserI2C {
> -    VirtIODevice parent;
> -    CharBackend chardev;
> -    struct vhost_virtqueue *vhost_vq;
> -    struct vhost_dev vhost_dev;
> -    VhostUserState vhost_user;
> -    VirtQueue *vq;
> -    bool connected;
> +    /*< private >*/
> +    VHostUserBase parent;
> +    /*< public >*/
>   };

And same again:

struct VHostUserI2C {
    VHostUserBase parent_obj;
};

> -/* Virtio Feature bits */
> -#define VIRTIO_I2C_F_ZERO_LENGTH_REQUEST               0
> -
>   #endif /* QEMU_VHOST_USER_I2C_H */
> diff --git a/hw/virtio/vhost-user-i2c.c b/hw/virtio/vhost-user-i2c.c
> index 60eaf0d95b..4a1f644a87 100644
> --- a/hw/virtio/vhost-user-i2c.c
> +++ b/hw/virtio/vhost-user-i2c.c
> @@ -14,237 +14,21 @@
>   #include "qemu/error-report.h"
>   #include "standard-headers/linux/virtio_ids.h"
>   
> -static const int feature_bits[] = {
> -    VIRTIO_I2C_F_ZERO_LENGTH_REQUEST,
> -    VIRTIO_F_RING_RESET,
> -    VHOST_INVALID_FEATURE_BIT
> +static Property vi2c_properties[] = {
> +    DEFINE_PROP_CHR("chardev", VHostUserBase, chardev),
> +    DEFINE_PROP_END_OF_LIST(),
>   };
>   
> -static void vu_i2c_start(VirtIODevice *vdev)
> -{
> -    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> -    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> -    VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
> -    int ret, i;
> -
> -    if (!k->set_guest_notifiers) {
> -        error_report("binding does not support guest notifiers");
> -        return;
> -    }
> -
> -    ret = vhost_dev_enable_notifiers(&i2c->vhost_dev, vdev);
> -    if (ret < 0) {
> -        error_report("Error enabling host notifiers: %d", -ret);
> -        return;
> -    }
> -
> -    ret = k->set_guest_notifiers(qbus->parent, i2c->vhost_dev.nvqs, true);
> -    if (ret < 0) {
> -        error_report("Error binding guest notifier: %d", -ret);
> -        goto err_host_notifiers;
> -    }
> -
> -    i2c->vhost_dev.acked_features = vdev->guest_features;
> -
> -    ret = vhost_dev_start(&i2c->vhost_dev, vdev, true);
> -    if (ret < 0) {
> -        error_report("Error starting vhost-user-i2c: %d", -ret);
> -        goto err_guest_notifiers;
> -    }
> -
> -    /*
> -     * guest_notifier_mask/pending not used yet, so just unmask
> -     * everything here. virtio-pci will do the right thing by
> -     * enabling/disabling irqfd.
> -     */
> -    for (i = 0; i < i2c->vhost_dev.nvqs; i++) {
> -        vhost_virtqueue_mask(&i2c->vhost_dev, vdev, i, false);
> -    }
> -
> -    return;
> -
> -err_guest_notifiers:
> -    k->set_guest_notifiers(qbus->parent, i2c->vhost_dev.nvqs, false);
> -err_host_notifiers:
> -    vhost_dev_disable_notifiers(&i2c->vhost_dev, vdev);
> -}
> -
> -static void vu_i2c_stop(VirtIODevice *vdev)
> -{
> -    VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
> -    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> -    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> -    int ret;
> -
> -    if (!k->set_guest_notifiers) {
> -        return;
> -    }
> -
> -    vhost_dev_stop(&i2c->vhost_dev, vdev, true);
> -
> -    ret = k->set_guest_notifiers(qbus->parent, i2c->vhost_dev.nvqs, false);
> -    if (ret < 0) {
> -        error_report("vhost guest notifier cleanup failed: %d", ret);
> -        return;
> -    }
> -
> -    vhost_dev_disable_notifiers(&i2c->vhost_dev, vdev);
> -}
> -
> -static void vu_i2c_set_status(VirtIODevice *vdev, uint8_t status)
> -{
> -    VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
> -    bool should_start = virtio_device_should_start(vdev, status);
> -
> -    if (vhost_dev_is_started(&i2c->vhost_dev) == should_start) {
> -        return;
> -    }
> -
> -    if (should_start) {
> -        vu_i2c_start(vdev);
> -    } else {
> -        vu_i2c_stop(vdev);
> -    }
> -}
> -
> -static uint64_t vu_i2c_get_features(VirtIODevice *vdev,
> -                                    uint64_t requested_features, Error **errp)
> -{
> -    VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
> -
> -    virtio_add_feature(&requested_features, VIRTIO_I2C_F_ZERO_LENGTH_REQUEST);
> -    return vhost_get_features(&i2c->vhost_dev, feature_bits, 
> requested_features);
> -}
> -
> -static void vu_i2c_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> -{
> -    /*
> -     * Not normally called; it's the daemon that handles the queue;
> -     * however virtio's cleanup path can call this.
> -     */
> -}
> -
> -static void vu_i2c_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
> -{
> -    VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
> -
> -    vhost_virtqueue_mask(&i2c->vhost_dev, vdev, idx, mask);
> -}
> -
> -static bool vu_i2c_guest_notifier_pending(VirtIODevice *vdev, int idx)
> -{
> -    VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
> -
> -    return vhost_virtqueue_pending(&i2c->vhost_dev, idx);
> -}
> -
> -static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserI2C *i2c)
> -{
> -    vhost_user_cleanup(&i2c->vhost_user);
> -    virtio_delete_queue(i2c->vq);
> -    virtio_cleanup(vdev);
> -}
> -
> -static int vu_i2c_connect(DeviceState *dev)
> -{
> -    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> -    VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
> -
> -    if (i2c->connected) {
> -        return 0;
> -    }
> -    i2c->connected = true;
> -
> -    /* restore vhost state */
> -    if (virtio_device_started(vdev, vdev->status)) {
> -        vu_i2c_start(vdev);
> -    }
> -
> -    return 0;
> -}
> -
> -static void vu_i2c_disconnect(DeviceState *dev)
> -{
> -    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> -    VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
> -
> -    if (!i2c->connected) {
> -        return;
> -    }
> -    i2c->connected = false;
> -
> -    if (vhost_dev_is_started(&i2c->vhost_dev)) {
> -        vu_i2c_stop(vdev);
> -    }
> -}
> -
> -static void vu_i2c_event(void *opaque, QEMUChrEvent event)
> +static void vi2c_realize(DeviceState *dev, Error **errp)
>   {
> -    DeviceState *dev = opaque;
> -    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> -    VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
> -
> -    switch (event) {
> -    case CHR_EVENT_OPENED:
> -        if (vu_i2c_connect(dev) < 0) {
> -            qemu_chr_fe_disconnect(&i2c->chardev);
> -            return;
> -        }
> -        break;
> -    case CHR_EVENT_CLOSED:
> -        vu_i2c_disconnect(dev);
> -        break;
> -    case CHR_EVENT_BREAK:
> -    case CHR_EVENT_MUX_IN:
> -    case CHR_EVENT_MUX_OUT:
> -        /* Ignore */
> -        break;
> -    }
> -}
> -
> -static void vu_i2c_device_realize(DeviceState *dev, Error **errp)
> -{
> -    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> -    VHostUserI2C *i2c = VHOST_USER_I2C(dev);
> -    int ret;
> -
> -    if (!i2c->chardev.chr) {
> -        error_setg(errp, "vhost-user-i2c: missing chardev");
> -        return;
> -    }
> -
> -    if (!vhost_user_init(&i2c->vhost_user, &i2c->chardev, errp)) {
> -        return;
> -    }
> -
> -    virtio_init(vdev, VIRTIO_ID_I2C_ADAPTER, 0);
> +    VHostUserBase *vub = VHOST_USER_BASE(dev);
> +    VHostUserBaseClass *vubc = VHOST_USER_BASE_GET_CLASS(dev);
>   
> -    i2c->vhost_dev.nvqs = 1;
> -    i2c->vq = virtio_add_queue(vdev, 4, vu_i2c_handle_output);
> -    i2c->vhost_dev.vqs = g_new0(struct vhost_virtqueue, i2c->vhost_dev.nvqs);
> +    /* Fixed for I2C */
> +    vub->virtio_id = VIRTIO_ID_I2C_ADAPTER;
> +    vub->num_vqs = 1;
>   
> -    ret = vhost_dev_init(&i2c->vhost_dev, &i2c->vhost_user,
> -                         VHOST_BACKEND_TYPE_USER, 0, errp);
> -    if (ret < 0) {
> -        g_free(i2c->vhost_dev.vqs);
> -        do_vhost_user_cleanup(vdev, i2c);
> -    }
> -
> -    qemu_chr_fe_set_handlers(&i2c->chardev, NULL, NULL, vu_i2c_event, NULL,
> -                             dev, NULL, true);
> -}
> -
> -static void vu_i2c_device_unrealize(DeviceState *dev)
> -{
> -    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> -    VHostUserI2C *i2c = VHOST_USER_I2C(dev);
> -    struct vhost_virtqueue *vhost_vqs = i2c->vhost_dev.vqs;
> -
> -    /* This will stop vhost backend if appropriate. */
> -    vu_i2c_set_status(vdev, 0);
> -    vhost_dev_cleanup(&i2c->vhost_dev);
> -    g_free(vhost_vqs);
> -    do_vhost_user_cleanup(vdev, i2c);
> +    vubc->parent_realize(dev, errp);
>   }
>   
>   static const VMStateDescription vu_i2c_vmstate = {
> @@ -252,30 +36,21 @@ static const VMStateDescription vu_i2c_vmstate = {
>       .unmigratable = 1,
>   };
>   
> -static Property vu_i2c_properties[] = {
> -    DEFINE_PROP_CHR("chardev", VHostUserI2C, chardev),
> -    DEFINE_PROP_END_OF_LIST(),
> -};
> -
>   static void vu_i2c_class_init(ObjectClass *klass, void *data)
>   {
>       DeviceClass *dc = DEVICE_CLASS(klass);
> -    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
> +    VHostUserBaseClass *vubc = VHOST_USER_BASE_CLASS(klass);
>   
> -    device_class_set_props(dc, vu_i2c_properties);
>       dc->vmsd = &vu_i2c_vmstate;
> +    device_class_set_props(dc, vi2c_properties);
> +    device_class_set_parent_realize(dc, vi2c_realize,
> +                                    &vubc->parent_realize);
>       set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
> -    vdc->realize = vu_i2c_device_realize;
> -    vdc->unrealize = vu_i2c_device_unrealize;
> -    vdc->get_features = vu_i2c_get_features;
> -    vdc->set_status = vu_i2c_set_status;
> -    vdc->guest_notifier_mask = vu_i2c_guest_notifier_mask;
> -    vdc->guest_notifier_pending = vu_i2c_guest_notifier_pending;
>   }
>   
>   static const TypeInfo vu_i2c_info = {
>       .name = TYPE_VHOST_USER_I2C,
> -    .parent = TYPE_VIRTIO_DEVICE,
> +    .parent = TYPE_VHOST_USER_BASE,
>       .instance_size = sizeof(VHostUserI2C),
>       .class_init = vu_i2c_class_init,
>   };
> diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
> index 8c6cb2143d..31c0406f05 100644
> --- a/hw/virtio/meson.build
> +++ b/hw/virtio/meson.build
> @@ -10,6 +10,9 @@ softmmu_virtio_ss.add(when: ['CONFIG_VIRTIO_PCI', 
> 'CONFIG_VHOST_USER_RNG'],
>   softmmu_virtio_ss.add(when: 'CONFIG_VHOST_USER_GPIO', if_true: 
> files('vhost-user-gpio.c'))
>   softmmu_virtio_ss.add(when: ['CONFIG_VIRTIO_PCI', 'CONFIG_VHOST_USER_GPIO'],
>                         if_true: files('vhost-user-gpio-pci.c'))
> +softmmu_virtio_ss.add(when: 'CONFIG_VHOST_USER_I2C', if_true: 
> files('vhost-user-i2c.c'))
> +softmmu_virtio_ss.add(when: ['CONFIG_VIRTIO_PCI', 'CONFIG_VHOST_USER_I2C'],
> +                       if_true: files('vhost-user-i2c-pci.c'))
>   
>   specific_virtio_ss = ss.source_set()
>   specific_virtio_ss.add(files('virtio.c'))
> @@ -39,14 +42,12 @@ specific_virtio_ss.add(when: 'CONFIG_VHOST_USER_VSOCK', 
> if_true: files('vhost-us
>   specific_virtio_ss.add(when: 'CONFIG_VIRTIO_RNG', if_true: 
> files('virtio-rng.c'))
>   specific_virtio_ss.add(when: 'CONFIG_VIRTIO_IOMMU', if_true: 
> files('virtio-iommu.c'))
>   specific_virtio_ss.add(when: 'CONFIG_VIRTIO_MEM', if_true: 
> files('virtio-mem.c'))
> -specific_virtio_ss.add(when: 'CONFIG_VHOST_USER_I2C', if_true: 
> files('vhost-user-i2c.c'))
>   specific_virtio_ss.add(when: 'CONFIG_VHOST_VDPA_DEV', if_true: 
> files('vdpa-dev.c'))
>   
>   virtio_pci_ss = ss.source_set()
>   virtio_pci_ss.add(when: 'CONFIG_VHOST_VSOCK', if_true: 
> files('vhost-vsock-pci.c'))
>   virtio_pci_ss.add(when: 'CONFIG_VHOST_USER_VSOCK', if_true: 
> files('vhost-user-vsock-pci.c'))
>   virtio_pci_ss.add(when: 'CONFIG_VHOST_USER_BLK', if_true: 
> files('vhost-user-blk-pci.c'))
> -virtio_pci_ss.add(when: 'CONFIG_VHOST_USER_I2C', if_true: 
> files('vhost-user-i2c-pci.c'))
>   virtio_pci_ss.add(when: 'CONFIG_VHOST_USER_INPUT', if_true: 
> files('vhost-user-input-pci.c'))
>   virtio_pci_ss.add(when: 'CONFIG_VHOST_USER_SCSI', if_true: 
> files('vhost-user-scsi-pci.c'))
>   virtio_pci_ss.add(when: 'CONFIG_VHOST_SCSI', if_true: 
> files('vhost-scsi-pci.c'))

Otherwise:

Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>


ATB,

Mark.