Re: [PATCH v3 3/5] virtio-pci: add support for configure interrupt

[Cindy Lu]

On Wed, Jan 27, 2021 at 1:44 PM Jason Wang <jasowang@redhat.com> wrote:
>
>
> On 2021/1/26 下午3:42, 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 | 92 ++++++++++++++++++++++++++++++++++--------
> >   1 file changed, 75 insertions(+), 17 deletions(-)
> >
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > index 36524a5728..8e192600b8 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -664,7 +664,6 @@ static uint32_t virtio_read_config(PCIDevice *pci_dev,
> >   }
> >
> >   static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy,
> > -                                        unsigned int queue_no,
> >                                           unsigned int vector)
> >   {
> >       VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
> > @@ -691,23 +690,17 @@ static void 
> > kvm_virtio_pci_vq_vector_release(VirtIOPCIProxy *proxy,
> >   }
> >
> >   static int kvm_virtio_pci_irqfd_use(VirtIOPCIProxy *proxy,
> > -                                 unsigned int queue_no,
> > +                                 EventNotifier *n,
> >                                    unsigned int vector)
> >   {
> >       VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
> > -    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> > -    VirtQueue *vq = virtio_get_queue(vdev, queue_no);
> > -    EventNotifier *n = virtio_queue_get_guest_notifier(vq);
> >       return kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL, 
> > irqfd->virq);
> >   }
> >
> >   static void kvm_virtio_pci_irqfd_release(VirtIOPCIProxy *proxy,
> > -                                      unsigned int queue_no,
> > +                                      EventNotifier *n ,
> >                                         unsigned int vector)
> >   {
> > -    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> > -    VirtQueue *vq = virtio_get_queue(vdev, queue_no);
> > -    EventNotifier *n = virtio_queue_get_guest_notifier(vq);
> >       VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
> >       int ret;
> >
> > @@ -722,7 +715,8 @@ static int kvm_virtio_pci_vector_use(VirtIOPCIProxy 
> > *proxy, int nvqs)
> >       VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
> >       unsigned int vector;
> >       int ret, queue_no;
> > -
> > +    VirtQueue *vq;
> > +    EventNotifier *n;
>
>
> new line is needed.
>
will fix this
>
> >       for (queue_no = 0; queue_no < nvqs; queue_no++) {
> >           if (!virtio_queue_get_num(vdev, queue_no)) {
> >               break;
> > @@ -731,7 +725,7 @@ static int kvm_virtio_pci_vector_use(VirtIOPCIProxy 
> > *proxy, int nvqs)
> >           if (vector >= msix_nr_vectors_allocated(dev)) {
> >               continue;
> >           }
> > -        ret = kvm_virtio_pci_vq_vector_use(proxy, queue_no, vector);
> > +        ret = kvm_virtio_pci_vq_vector_use(proxy,  vector);
> >           if (ret < 0) {
> >               goto undo;
> >           }
> > @@ -739,7 +733,9 @@ static int kvm_virtio_pci_vector_use(VirtIOPCIProxy 
> > *proxy, int nvqs)
> >            * Otherwise, delay until unmasked in the frontend.
> >            */
> >           if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
> > -            ret = kvm_virtio_pci_irqfd_use(proxy, queue_no, vector);
> > +            vq = virtio_get_queue(vdev, queue_no);
> > +            n = virtio_queue_get_guest_notifier(vq);
> > +            ret = kvm_virtio_pci_irqfd_use(proxy, n, vector);
> >               if (ret < 0) {
> >                   kvm_virtio_pci_vq_vector_release(proxy, vector);
> >                   goto undo;
> > @@ -755,13 +751,69 @@ undo:
> >               continue;
> >           }
> >           if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
> > -            kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
> > +            vq = virtio_get_queue(vdev, queue_no);
> > +            n = virtio_queue_get_guest_notifier(vq);
> > +            kvm_virtio_pci_irqfd_release(proxy, n, vector);
> >           }
> >           kvm_virtio_pci_vq_vector_release(proxy, vector);
> >       }
> >       return ret;
> >   }
> >
> > +static int kvm_virtio_pci_vector_config_use(VirtIOPCIProxy *proxy)
> > +{
> > +
> > +    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> > +    unsigned int vector;
> > +    int ret;
> > +    EventNotifier *n = virtio_get_config_notifier(vdev);
> > +
> > +    vector = vdev->config_vector ;
> > +    ret = kvm_virtio_pci_vq_vector_use(proxy, vector);
> > +    if (ret < 0) {
> > +        goto undo;
> > +    }
> > +    ret = kvm_virtio_pci_irqfd_use(proxy,  n, vector);
> > +    if (ret < 0) {
> > +        goto undo;
> > +    }
> > +    return 0;
> > +undo:
> > +    kvm_virtio_pci_irqfd_release(proxy, n, vector);
> > +    return ret;
> > +}
>
>
> newline is needed.
>
will fix this
>
> > +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;
> > +    EventNotifier *n = virtio_get_config_notifier(vdev);
> > +    vector = vdev->config_vector ;
> > +    if (vector >= msix_nr_vectors_allocated(dev)) {
> > +        return;
> > +    }
> > +    kvm_virtio_pci_irqfd_release(proxy, n, vector);
> > +    kvm_virtio_pci_vq_vector_release(proxy, vector);
> > +}
> > +
> > +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_config_notifier_fd_handler(vdev, true, true);
> > +        kvm_virtio_pci_vector_config_use(proxy);
> > +    } else {
> > +        virtio_set_config_notifier_fd_handler(vdev, false, true);
> > +        kvm_virtio_pci_vector_config_release(proxy);
> > +        event_notifier_cleanup(notifier);
> > +    }
> > +    return r;
> > +}
>
>
> Two questions, don't we need to check whether or not MSIX is enalbed in
> this case? Instead of introducing new helpers that is easy to be buggy I
> still prefer to re-use virtio_pci_set_guest_notifier:
>
> We can switch to use accepts EventNotifier instead of virtqueue index.
> And we need also convert virtqueue_set_guest_notifier_fd_handler() to
> accept EventNotifier.
>
sure, I will fix this
>
> > +
> >   static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
> >   {
> >       PCIDevice *dev = &proxy->pci_dev;
> > @@ -769,7 +821,8 @@ static void 
> > kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
> >       unsigned int vector;
> >       int queue_no;
> >       VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
> > -
> > +    VirtQueue *vq;
> > +    EventNotifier *n;
>
>
> newline is needed.
>
> Thanks
>
>
> >       for (queue_no = 0; queue_no < nvqs; queue_no++) {
> >           if (!virtio_queue_get_num(vdev, queue_no)) {
> >               break;
> > @@ -782,7 +835,9 @@ static void 
> > kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
> >            * Otherwise, it was cleaned when masked in the frontend.
> >            */
> >           if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
> > -            kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
> > +            vq = virtio_get_queue(vdev, queue_no);
> > +            n = virtio_queue_get_guest_notifier(vq);
> > +            kvm_virtio_pci_irqfd_release(proxy, n, vector);
> >           }
> >           kvm_virtio_pci_vq_vector_release(proxy, vector);
> >       }
> > @@ -823,7 +878,7 @@ static int virtio_pci_vq_vector_unmask(VirtIOPCIProxy 
> > *proxy,
> >               event_notifier_set(n);
> >           }
> >       } else {
> > -        ret = kvm_virtio_pci_irqfd_use(proxy, queue_no, vector);
> > +        ret = kvm_virtio_pci_irqfd_use(proxy, n, vector);
> >       }
> >       return ret;
> >   }
> > @@ -835,13 +890,15 @@ static void virtio_pci_vq_vector_mask(VirtIOPCIProxy 
> > *proxy,
> >       VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> >       VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
> >
> > +    VirtQueue *vq = virtio_get_queue(vdev, queue_no);
> > +    EventNotifier *n = virtio_queue_get_guest_notifier(vq);
> >       /* If guest supports masking, keep irqfd but mask it.
> >        * Otherwise, clean it up now.
> >        */
> >       if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
> >           k->guest_notifier_mask(vdev, queue_no, true);
> >       } else {
> > -        kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
> > +        kvm_virtio_pci_irqfd_release(proxy, n, vector);
> >       }
> >   }
> >
> > @@ -2137,6 +2194,7 @@ 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_config_notifier;
> >   }
> >
> >   static const TypeInfo virtio_pci_bus_info = {
>