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

Jason Wang
2022-04-14T09:16:39Z

On Wed, Apr 13, 2022 at 10:30 AM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
>
> On Tue, 12 Apr 2022 10:41:03 +0800, Jason Wang <jasowang@redhat.com> 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@linux.alibaba.com>
> > > ---
> > > 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);
> >
>