Re: [PATCH v9 22/32] virtio_pci: queue_reset: extract the logic of active vq for modern pci

Jason Wang
2022-04-14T09:38:14Z

On Thu, Apr 14, 2022 at 2:25 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
>
> On Tue, 12 Apr 2022 14:58:19 +0800, Jason Wang <jasowang@redhat.com> wrote:
> >
> > 在 2022/4/6 上午11:43, Xuan Zhuo 写道:
> > > Introduce vp_active_vq() to configure vring to backend after vq attach
> > > vring. And configure vq vector if necessary.
> > >
> > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > > ---
> > > drivers/virtio/virtio_pci_modern.c | 46 ++++++++++++++++++------------
> > > 1 file changed, 28 insertions(+), 18 deletions(-)
> > >
> > > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> > > index 86d301f272b8..49a4493732cf 100644
> > > --- a/drivers/virtio/virtio_pci_modern.c
> > > +++ b/drivers/virtio/virtio_pci_modern.c
> > > @@ -176,6 +176,29 @@ static void vp_reset(struct virtio_device *vdev)
> > > vp_disable_cbs(vdev);
> > > }
> > >
> > > +static int vp_active_vq(struct virtqueue *vq, u16 msix_vec)
> > > +{
> > > + struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
> > > + struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> > > + unsigned long index;
> > > +
> > > + index = vq->index;
> > > +
> > > + /* activate the queue */
> > > + vp_modern_set_queue_size(mdev, index, virtqueue_get_vring_size(vq));
> > > + vp_modern_queue_address(mdev, index, virtqueue_get_desc_addr(vq),
> > > + virtqueue_get_avail_addr(vq),
> > > + virtqueue_get_used_addr(vq));
> > > +
> > > + if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
> > > + msix_vec = vp_modern_queue_vector(mdev, index, msix_vec);
> > > + if (msix_vec == VIRTIO_MSI_NO_VECTOR)
> > > + return -EBUSY;
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
> > > {
> > > return vp_modern_config_vector(&vp_dev->mdev, vector);
> > > @@ -220,32 +243,19 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > >
> > > vq->num_max = num;
> > >
> > > - /* activate the queue */
> > > - vp_modern_set_queue_size(mdev, index, virtqueue_get_vring_size(vq));
> > > - vp_modern_queue_address(mdev, index, virtqueue_get_desc_addr(vq),
> > > - virtqueue_get_avail_addr(vq),
> > > - virtqueue_get_used_addr(vq));
> > > + err = vp_active_vq(vq, msix_vec);
> > > + if (err)
> > > + goto err;
> > >
> > > vq->priv = (void __force *)vp_modern_map_vq_notify(mdev, index, NULL);
> > > if (!vq->priv) {
> > > err = -ENOMEM;
> > > - goto err_map_notify;
> > > - }
> > > -
> > > - if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
> > > - msix_vec = vp_modern_queue_vector(mdev, index, msix_vec);
> > > - if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
> > > - err = -EBUSY;
> > > - goto err_assign_vector;
> > > - }
> > > + goto err;
> > > }
> > >
> > > return vq;
> > >
> > > -err_assign_vector:
> > > - if (!mdev->notify_base)
> > > - pci_iounmap(mdev->pci_dev, (void __iomem __force *)vq->priv);
> >
> >
> > We need keep this or anything I missed?
>
> I think so, after modification, vp_modern_map_vq_notify is the last step before
> returning vq. If it fails, then vq->priv is equal to NULL, so there is no need
> to execute pci_iounmap.
>
> Did I miss something?

Nope I miss that the vector is configured before the mapping.

So

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

>
> Thanks.
>
> >
> > Thanks
> >
> >
> > > -err_map_notify:
> > > +err:
> > > vring_del_virtqueue(vq);
> > > return ERR_PTR(err);
> > > }
> >
>