Re: [PATCH v9 01/32] virtio: add helper virtqueue_get_vring_max_size()

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On Wed, Apr 13, 2022 at 10:30 AM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> On Tue, 12 Apr 2022 10:41:03 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote:
> >
> > 在 2022/4/6 上午11:43, Xuan Zhuo 写道:
> > > Record the maximum queue num supported by the device.
> > >
> > > virtio-net can display the maximum (supported by hardware) ring size in
> > > ethtool -g eth0.
> > >
> > > When the subsequent patch implements vring reset, it can judge whether
> > > the ring size passed by the driver is legal based on this.
> > >
> > > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> > > ---
> > >   arch/um/drivers/virtio_uml.c             |  1 +
> > >   drivers/platform/mellanox/mlxbf-tmfifo.c |  2 ++
> > >   drivers/remoteproc/remoteproc_virtio.c   |  2 ++
> > >   drivers/s390/virtio/virtio_ccw.c         |  3 +++
> > >   drivers/virtio/virtio_mmio.c             |  2 ++
> > >   drivers/virtio/virtio_pci_legacy.c       |  2 ++
> > >   drivers/virtio/virtio_pci_modern.c       |  2 ++
> > >   drivers/virtio/virtio_ring.c             | 14 ++++++++++++++
> > >   drivers/virtio/virtio_vdpa.c             |  2 ++
> > >   include/linux/virtio.h                   |  2 ++
> > >   10 files changed, 32 insertions(+)
> > >
> > > diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
> > > index ba562d68dc04..904993d15a85 100644
> > > --- a/arch/um/drivers/virtio_uml.c
> > > +++ b/arch/um/drivers/virtio_uml.c
> > > @@ -945,6 +945,7 @@ static struct virtqueue *vu_setup_vq(struct virtio_device *vdev,
> > >             goto error_create;
> > >     }
> > >     vq->priv = info;
> > > +   vq->num_max = num;
> > >     num = virtqueue_get_vring_size(vq);
> > >
> > >     if (vu_dev->protocol_features &
> > > diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c
> > > index 38800e86ed8a..1ae3c56b66b0 100644
> > > --- a/drivers/platform/mellanox/mlxbf-tmfifo.c
> > > +++ b/drivers/platform/mellanox/mlxbf-tmfifo.c
> > > @@ -959,6 +959,8 @@ static int mlxbf_tmfifo_virtio_find_vqs(struct virtio_device *vdev,
> > >                     goto error;
> > >             }
> > >
> > > +           vq->num_max = vring->num;
> > > +
> > >             vqs[i] = vq;
> > >             vring->vq = vq;
> > >             vq->priv = vring;
> > > diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
> > > index 70ab496d0431..7611755d0ae2 100644
> > > --- a/drivers/remoteproc/remoteproc_virtio.c
> > > +++ b/drivers/remoteproc/remoteproc_virtio.c
> > > @@ -125,6 +125,8 @@ static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
> > >             return ERR_PTR(-ENOMEM);
> > >     }
> > >
> > > +   vq->num_max = len;
> >
> >
> > I wonder if this is correct.
> >
> > It looks to me len is counted in bytes:
> >
> > /**
> >   * struct rproc_vring - remoteproc vring state
> >   * @va: virtual address
> >   * @len: length, in bytes
> >   * @da: device address
> >   * @align: vring alignment
> >   * @notifyid: rproc-specific unique vring index
> >   * @rvdev: remote vdev
> >   * @vq: the virtqueue of this vring
> >   */
> > struct rproc_vring {
> >          void *va;
> >          int len;
> >          u32 da;
> >          u32 align;
> >          int notifyid;
> >          struct rproc_vdev *rvdev;
> >          struct virtqueue *vq;
> > };
> >
>
> I think this comment is incorrect because here len is passed as num to
> vring_new_virtqueue().
>
> There is also this usage:
>
>         /* actual size of vring (in bytes) */
>         size = PAGE_ALIGN(vring_size(rvring->len, rvring->align));
>
>
> And this value comes from here:
>
>         static int
>         rproc_parse_vring(struct rproc_vdev *rvdev, struct fw_rsc_vdev *rsc, int i)
>         {
>                 struct rproc *rproc = rvdev->rproc;
>                 struct device *dev = &rproc->dev;
>                 struct fw_rsc_vdev_vring *vring = &rsc->vring[i];
>                 struct rproc_vring *rvring = &rvdev->vring[i];
>
>                 dev_dbg(dev, "vdev rsc: vring%d: da 0x%x, qsz %d, align %d\n",
>                         i, vring->da, vring->num, vring->align);
>
>                 /* verify queue size and vring alignment are sane */
>                 if (!vring->num || !vring->align) {
>                         dev_err(dev, "invalid qsz (%d) or alignment (%d)\n",
>                                 vring->num, vring->align);
>                         return -EINVAL;
>                 }
>
>        >        rvring->len = vring->num;
>                 rvring->align = vring->align;
>                 rvring->rvdev = rvdev;
>
>                 return 0;
>         }
>
> /**
>  * struct fw_rsc_vdev_vring - vring descriptor entry
>  * @da: device address
>  * @align: the alignment between the consumer and producer parts of the vring
>  * @num: num of buffers supported by this vring (must be power of two)
>  * @notifyid: a unique rproc-wide notify index for this vring. This notify
>  * index is used when kicking a remote processor, to let it know that this
>  * vring is triggered.
>  * @pa: physical address
>  *
>  * This descriptor is not a resource entry by itself; it is part of the
>  * vdev resource type (see below).
>  *
>  * Note that @da should either contain the device address where
>  * the remote processor is expecting the vring, or indicate that
>  * dynamically allocation of the vring's device address is supported.
>  */
> struct fw_rsc_vdev_vring {
>         u32 da;
>         u32 align;
>         u32 num;
>         u32 notifyid;
>         u32 pa;
> } __packed;
>
> So I think the 'len' here may have changed its meaning in a version update.

I think you're right, let's have a patch to fix the comment (probably
with the name since len is confusing here).

Thanks

>
> Thanks.
>
> >
> > Other looks good.
> >
> > Thanks
> >
> >
> > > +
> > >     rvring->vq = vq;
> > >     vq->priv = rvring;
> > >
> > > diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
> > > index d35e7a3f7067..468da60b56c5 100644
> > > --- a/drivers/s390/virtio/virtio_ccw.c
> > > +++ b/drivers/s390/virtio/virtio_ccw.c
> > > @@ -529,6 +529,9 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
> > >             err = -ENOMEM;
> > >             goto out_err;
> > >     }
> > > +
> > > +   vq->num_max = info->num;
> > > +
> > >     /* it may have been reduced */
> > >     info->num = virtqueue_get_vring_size(vq);
> > >
> > > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> > > index 56128b9c46eb..a41abc8051b9 100644
> > > --- a/drivers/virtio/virtio_mmio.c
> > > +++ b/drivers/virtio/virtio_mmio.c
> > > @@ -390,6 +390,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
> > >             goto error_new_virtqueue;
> > >     }
> > >
> > > +   vq->num_max = num;
> > > +
> > >     /* Activate the queue */
> > >     writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
> > >     if (vm_dev->version == 1) {
> > > diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
> > > index 34141b9abe27..b68934fe6b5d 100644
> > > --- a/drivers/virtio/virtio_pci_legacy.c
> > > +++ b/drivers/virtio/virtio_pci_legacy.c
> > > @@ -135,6 +135,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > >     if (!vq)
> > >             return ERR_PTR(-ENOMEM);
> > >
> > > +   vq->num_max = num;
> > > +
> > >     q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
> > >     if (q_pfn >> 32) {
> > >             dev_err(&vp_dev->pci_dev->dev,
> > > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> > > index 5455bc041fb6..86d301f272b8 100644
> > > --- a/drivers/virtio/virtio_pci_modern.c
> > > +++ b/drivers/virtio/virtio_pci_modern.c
> > > @@ -218,6 +218,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > >     if (!vq)
> > >             return ERR_PTR(-ENOMEM);
> > >
> > > +   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),
> > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > > index 962f1477b1fa..b87130c8f312 100644
> > > --- a/drivers/virtio/virtio_ring.c
> > > +++ b/drivers/virtio/virtio_ring.c
> > > @@ -2371,6 +2371,20 @@ void vring_transport_features(struct virtio_device *vdev)
> > >   }
> > >   EXPORT_SYMBOL_GPL(vring_transport_features);
> > >
> > > +/**
> > > + * virtqueue_get_vring_max_size - return the max size of the virtqueue's vring
> > > + * @_vq: the struct virtqueue containing the vring of interest.
> > > + *
> > > + * Returns the max size of the vring.
> > > + *
> > > + * Unlike other operations, this need not be serialized.
> > > + */
> > > +unsigned int virtqueue_get_vring_max_size(struct virtqueue *_vq)
> > > +{
> > > +   return _vq->num_max;
> > > +}
> > > +EXPORT_SYMBOL_GPL(virtqueue_get_vring_max_size);
> > > +
> > >   /**
> > >    * virtqueue_get_vring_size - return the size of the virtqueue's vring
> > >    * @_vq: the struct virtqueue containing the vring of interest.
> > > diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
> > > index 7767a7f0119b..39e4c08eb0f2 100644
> > > --- a/drivers/virtio/virtio_vdpa.c
> > > +++ b/drivers/virtio/virtio_vdpa.c
> > > @@ -183,6 +183,8 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
> > >             goto error_new_virtqueue;
> > >     }
> > >
> > > +   vq->num_max = max_num;
> > > +
> > >     /* Setup virtqueue callback */
> > >     cb.callback = virtio_vdpa_virtqueue_cb;
> > >     cb.private = info;
> > > diff --git a/include/linux/virtio.h b/include/linux/virtio.h
> > > index 72292a62cd90..d59adc4be068 100644
> > > --- a/include/linux/virtio.h
> > > +++ b/include/linux/virtio.h
> > > @@ -31,6 +31,7 @@ struct virtqueue {
> > >     struct virtio_device *vdev;
> > >     unsigned int index;
> > >     unsigned int num_free;
> > > +   unsigned int num_max;
> > >     void *priv;
> > >   };
> > >
> > > @@ -80,6 +81,7 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
> > >
> > >   void *virtqueue_detach_unused_buf(struct virtqueue *vq);
> > >
> > > +unsigned int virtqueue_get_vring_max_size(struct virtqueue *vq);
> > >   unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
> > >
> > >   bool virtqueue_is_broken(struct virtqueue *vq);
> >
>





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