Re: [PATCH v7 03/26] virtio: add helper virtqueue_get_vring_max_size()

[Jason Wang <jasowang@redhat.com>]

在 2022/3/8 下午8:34, 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>


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


> ---
>   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 ++++++++++++++
>   include/linux/virtio.h             |  2 ++
>   5 files changed, 22 insertions(+)
>
> 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/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);