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

[Cindy Lu]

On Thu, Jun 3, 2021 at 2:45 PM Jason Wang <jasowang@redhat.com> wrote:
>
>
> 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?
>
sure, will fix this , I have tried checkpatch.pl?, but seems it not
working correctly in my environment
>
> > +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.
>
sure ,I  will move this section
>
> >       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.
>
>
Will do this
> >   }
> >
> >   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
>
>
will correct this

> > +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);
>