Re: [PATCH v1 2/4] virtio-pci:add support for configure interrupt

[Jason Wang]

On 2021/1/13 下午11:45, Cindy Lu wrote:
> Add support for configure interrupt, use kvm_irqfd_assign and set the
> gsi to kernel. When the configure notifier was eventfd_signal by host
> kernel, this will finally inject an msix interrupt to guest
>
> Signed-off-by: Cindy Lu <lulu@redhat.com>
> ---
>   hw/virtio/virtio-pci.c         | 93 ++++++++++++++++++++++++++++++++++
>   include/hw/virtio/virtio-bus.h |  2 +
>   2 files changed, 95 insertions(+)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 36524a5728..f8053e1fab 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -762,6 +762,98 @@ undo:
>       return ret;
>   }
>   
> + static int kvm_virtio_pci_config_irqfd_use(VirtIOPCIProxy *proxy,
> +                                 unsigned int vector)
> +{
> +    VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
> +    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> +    EventNotifier *n = virtio_queue_get_config_notifier(vdev);
> +    assert(irqfd);
> +    return kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL, irqfd->virq);
> +}
> +
> +static void kvm_virtio_pci_config_irqfd_release(VirtIOPCIProxy *proxy,
> +                                      unsigned int vector)
> +{
> +    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> +    EventNotifier *n = virtio_queue_get_config_notifier(vdev);
> +    VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
> +    assert(irqfd);
> +    kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state, n, irqfd->virq);
> +    return;
> +}
> +static int kvm_virtio_pci_config_vector_use(VirtIOPCIProxy *proxy,
> +                                        unsigned int vector)
> +{
> +    VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
> +    int ret;
> +
> +    if (irqfd->users == 0) {
> +        ret = kvm_irqchip_add_msi_route(kvm_state, vector, &proxy->pci_dev);
> +        if (ret < 0) {
> +            return ret;
> +        }
> +        irqfd->virq = ret;
> +    }
> +    irqfd->users++;
> +
> +    return 0;
> +}


Any reason that we can't resue kvm_virtio_pci_vq_vector_use()? Note that 
at MSIX level there's no difference if it belongs to vq or config.


> +static int kvm_virtio_pci_vector_config_use(VirtIOPCIProxy *proxy)
> +{
> +
> +    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> +    unsigned int vector;
> +    int ret;
> +    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
> +
> +    vector = vdev->config_vector ;
> +    ret = kvm_virtio_pci_config_vector_use(proxy, vector);
> +    if (ret < 0) {
> +        goto undo;
> +    }
> +    ret = kvm_virtio_pci_config_irqfd_use(proxy,  vector);
> +    if (ret < 0) {
> +        goto undo;
> +    }
> +    return 0;
> +undo:
> +    kvm_virtio_pci_config_irqfd_release(proxy, vector);
> +    return ret;
> +}
> +static void kvm_virtio_pci_vector_config_release(VirtIOPCIProxy *proxy)
> +{
> +    PCIDevice *dev = &proxy->pci_dev;
> +    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> +    unsigned int vector;
> +    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
> +    vector = vdev->config_vector ;
> +    if (vector >= msix_nr_vectors_allocated(dev)) {
> +        return;
> +    }
> +    kvm_virtio_pci_config_irqfd_release(proxy, vector);
> +    kvm_virtio_pci_vq_vector_release(proxy, vector);
> +}
> +
> +static int virtio_pci_set_guest_config_notifier(DeviceState *d,  bool assign,
> +                                         bool with_irqfd)
> +{
> +    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);
> +    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> +    EventNotifier *notifier = virtio_queue_get_config_notifier(vdev);
> +    int r = 0;
> +    if (assign) {
> +        r = event_notifier_init(notifier, 1);
> +        virtio_set_config_notifier_fd_handler(vdev, true, with_irqfd);
> +        kvm_virtio_pci_vector_config_use(proxy);
> +    } else {
> +        virtio_set_config_notifier_fd_handler(vdev, false, with_irqfd);
> +        kvm_virtio_pci_vector_config_release(proxy);
> +        event_notifier_cleanup(notifier);
> +    }
> +    return r;
> +}


Any way to re-use virtio_pci_set_guest_notifier() here?

Thanks


> +
>   static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
>   {
>       PCIDevice *dev = &proxy->pci_dev;
> @@ -2137,6 +2229,7 @@ static void virtio_pci_bus_class_init(ObjectClass *klass, 
> void *data)
>       k->ioeventfd_assign = virtio_pci_ioeventfd_assign;
>       k->get_dma_as = virtio_pci_get_dma_as;
>       k->queue_enabled = virtio_pci_queue_enabled;
> +    k->set_config_notifiers = virtio_pci_set_guest_config_notifier;
>   }
>   
>   static const TypeInfo virtio_pci_bus_info = {
> diff --git a/include/hw/virtio/virtio-bus.h b/include/hw/virtio/virtio-bus.h
> index ef8abe49c5..dae81ee414 100644
> --- a/include/hw/virtio/virtio-bus.h
> +++ b/include/hw/virtio/virtio-bus.h
> @@ -93,6 +93,8 @@ struct VirtioBusClass {
>        */
>       bool has_variable_vring_alignment;
>       AddressSpace *(*get_dma_as)(DeviceState *d);
> +    int (*set_config_notifiers)(DeviceState *d, bool assign, bool with_irqfd);
> +
>   };
>   
>   struct VirtioBusState {