Re: [PATCH v7 09/10] virtio-pci: add support for configure interrupt

[Jason Wang <jasowang@redhat.com>]

在 2021/6/2 上午11:47, Cindy Lu 写道:
> 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 | 63 ++++++++++++++++++++++++++++++++++++++++--
>   1 file changed, 60 insertions(+), 3 deletions(-)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index f863c89de6..1e03f11a85 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -717,7 +717,8 @@ static int virtio_pci_get_notifier(VirtIOPCIProxy *proxy, int queue_no,
>       VirtQueue *vq;
>   
>       if (queue_no == VIRTIO_CONFIG_IRQ_IDX) {
> -        return -1;
> +        *n = virtio_get_config_notifier(vdev);
> +        *vector = vdev->config_vector;
>       } else {
>           if (!virtio_queue_get_num(vdev, queue_no)) {
>               return -1;
> @@ -764,6 +765,10 @@ static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs)
>       return ret;
>   }
>   
> +static int kvm_virtio_pci_vector_config_use(VirtIOPCIProxy *proxy)
> +{
> +    return kvm_virtio_pci_vector_use_one(proxy, VIRTIO_CONFIG_IRQ_IDX);
> +}
>   
>   static void kvm_virtio_pci_vector_release_one(VirtIOPCIProxy *proxy,
>                           int queue_no)
> @@ -792,6 +797,28 @@ static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
>       }
>   }
>   
> +static void kvm_virtio_pci_vector_config_release(VirtIOPCIProxy *proxy)
> +{
> +    kvm_virtio_pci_vector_release_one(proxy, VIRTIO_CONFIG_IRQ_IDX);
> +}


Newline please, can this survive from checkpatch.pl?


> +static int virtio_pci_set_config_notifier(DeviceState *d, bool assign)
> +{
> +    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);
> +    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> +    EventNotifier *notifier = virtio_get_config_notifier(vdev);
> +    int r = 0;
> +    if (assign) {
> +        r = event_notifier_init(notifier, 0);
> +        virtio_set_notifier_fd_handler(vdev, VIRTIO_CONFIG_IRQ_IDX, true, true);
> +        kvm_virtio_pci_vector_config_use(proxy);
> +    } else {
> +        virtio_set_notifier_fd_handler(vdev, VIRTIO_CONFIG_IRQ_IDX,
> +                                             false, true);
> +        kvm_virtio_pci_vector_config_release(proxy);
> +        event_notifier_cleanup(notifier);
> +    }
> +    return r;
> +}
>   static int virtio_pci_vq_vector_unmask(VirtIOPCIProxy *proxy,
>                                          unsigned int queue_no,
>                                          unsigned int vector,
> @@ -873,9 +900,17 @@ static int virtio_pci_vector_unmask(PCIDevice *dev, unsigned vector,
>           }
>           vq = virtio_vector_next_queue(vq);
>       }
> -
> +    n = virtio_get_config_notifier(vdev);
> +    ret = virtio_pci_vq_vector_unmask(proxy, VIRTIO_CONFIG_IRQ_IDX,
> +                        vector, msg, n);
> +    if (ret < 0) {
> +        goto config_undo;
> +    }


I'd do this before the loop, but need to validate whether the vector is 
the one that is used by the config interrupt.


>       return 0;
>   
> +config_undo:
> +    n = virtio_get_config_notifier(vdev);
> +    virtio_pci_vq_vector_mask(proxy, VIRTIO_CONFIG_IRQ_IDX, vector, n);


So unmask fail means it is still masked, we don't need to mask it again.


>   undo:
>       vq = virtio_vector_first_queue(vdev, vector);
>       while (vq && unmasked >= 0) {
> @@ -909,6 +944,8 @@ static void virtio_pci_vector_mask(PCIDevice *dev, unsigned vector)
>           }
>           vq = virtio_vector_next_queue(vq);
>       }
> +    n = virtio_get_config_notifier(vdev);
> +    virtio_pci_vq_vector_mask(proxy, VIRTIO_CONFIG_IRQ_IDX, vector, n);
>   }
>   
>   static void virtio_pci_vector_poll(PCIDevice *dev,
> @@ -942,6 +979,20 @@ static void virtio_pci_vector_poll(PCIDevice *dev,
>               msix_set_pending(dev, vector);
>           }
>       }
> +   /*check for config interrupt*/
> +   vector = vdev->config_vector;
> +   notifier = virtio_get_config_notifier(vdev);
> +   if (vector < vector_start || vector >= vector_end ||
> +            !msix_is_masked(dev, vector)) {
> +        return;
> +   }
> +   if (k->guest_notifier_pending) {
> +        if (k->guest_notifier_pending(vdev, VIRTIO_CONFIG_IRQ_IDX)) {
> +            msix_set_pending(dev, vector);
> +        }
> +   } else if (event_notifier_test_and_clear(notifier)) {
> +        msix_set_pending(dev, vector);
> +   }


Let's consider to unify the codes with vq vector here.


>   }
>   
>   static int virtio_pci_set_guest_notifier(DeviceState *d, int n, bool assign,
> @@ -1002,6 +1053,7 @@ static int virtio_pci_set_guest_notifiers(DeviceState *d, int nvqs, bool assign)
>           msix_unset_vector_notifiers(&proxy->pci_dev);
>           if (proxy->vector_irqfd) {
>               kvm_virtio_pci_vector_release(proxy, nvqs);
> +            kvm_virtio_pci_vector_config_release(proxy);
>               g_free(proxy->vector_irqfd);
>               proxy->vector_irqfd = NULL;
>           }
> @@ -1029,6 +1081,10 @@ static int virtio_pci_set_guest_notifiers(DeviceState *d, int nvqs, bool assign)
>                   goto assign_error;
>               }
>           }
> +        r = virtio_pci_set_config_notifier(d, assign);
> +        if (r < 0) {
> +            goto config_error;
> +        }
>           r = msix_set_vector_notifiers(&proxy->pci_dev,
>                                         virtio_pci_vector_unmask,
>                                         virtio_pci_vector_mask,
> @@ -1045,7 +1101,8 @@ notifiers_error:
>           assert(assign);
>           kvm_virtio_pci_vector_release(proxy, nvqs);
>       }
> -


Newline should be kept here.

Thanks


> +config_error:
> +    kvm_virtio_pci_vector_config_release(proxy);
>   assign_error:
>       /* We get here on assignment failure. Recover by undoing for VQs 0 .. n. */
>       assert(assign);