Subject: Re: [PATCH v14 30/42] virtio_pci: introduce helper to get/set queue reset

From: "Michael S. Tsirkin" <[email-masked]>
Date: Mon, 15 Aug 2022 02:07:05 -0400

On Mon, Aug 01, 2022 at 02:38:50PM +0800, Xuan Zhuo wrote:
> Introduce new helpers to implement queue reset and get queue reset
> status.
> 
>  https://github.com/oasis-tcs/virtio-spec/issues/124
>  https://github.com/oasis-tcs/virtio-spec/issues/139
> 
> Signed-off-by: Xuan Zhuo <[email-masked]>
> Acked-by: Jason Wang <[email-masked]>
> ---
>  drivers/virtio/virtio_pci_modern_dev.c | 39 ++++++++++++++++++++++++++
>  include/linux/virtio_pci_modern.h      |  2 ++
>  2 files changed, 41 insertions(+)
> 
> diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
> index fa2a9445bb18..869cb46bef96 100644
> --- a/drivers/virtio/virtio_pci_modern_dev.c
> +++ b/drivers/virtio/virtio_pci_modern_dev.c
> @@ -3,6 +3,7 @@
>  #include <linux/virtio_pci_modern.h>
>  #include <linux/module.h>
>  #include <linux/pci.h>
> +#include <linux/delay.h>
>  
>  /*
>   * vp_modern_map_capability - map a part of virtio pci capability
> @@ -474,6 +475,44 @@ void vp_modern_set_status(struct virtio_pci_modern_device *mdev,
>  }
>  EXPORT_SYMBOL_GPL(vp_modern_set_status);
>  
> +/*
> + * vp_modern_get_queue_reset - get the queue reset status
> + * @mdev: the modern virtio-pci device
> + * @index: queue index
> + */
> +int vp_modern_get_queue_reset(struct virtio_pci_modern_device *mdev, u16 index)
> +{
> +	struct virtio_pci_modern_common_cfg __iomem *cfg;
> +
> +	cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;

This should use container_of, and assignment combined with the
declaration.

> +
> +	vp_iowrite16(index, &cfg->cfg.queue_select);
> +	return vp_ioread16(&cfg->queue_reset);
> +}
> +EXPORT_SYMBOL_GPL(vp_modern_get_queue_reset);
> +
> +/*
> + * vp_modern_set_queue_reset - reset the queue
> + * @mdev: the modern virtio-pci device
> + * @index: queue index
> + */
> +void vp_modern_set_queue_reset(struct virtio_pci_modern_device *mdev, u16 index)
> +{
> +	struct virtio_pci_modern_common_cfg __iomem *cfg;
> +
> +	cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;
> +
> +	vp_iowrite16(index, &cfg->cfg.queue_select);
> +	vp_iowrite16(1, &cfg->queue_reset);
> +
> +	while (vp_ioread16(&cfg->queue_reset))
> +		msleep(1);
> +
> +	while (vp_ioread16(&cfg->cfg.queue_enable))
> +		msleep(1);
> +}
> +EXPORT_SYMBOL_GPL(vp_modern_set_queue_reset);
> +
>  /*
>   * vp_modern_queue_vector - set the MSIX vector for a specific virtqueue
>   * @mdev: the modern virtio-pci device
> diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
> index 05123b9a606f..c4eeb79b0139 100644
> --- a/include/linux/virtio_pci_modern.h
> +++ b/include/linux/virtio_pci_modern.h
> @@ -113,4 +113,6 @@ void __iomem * vp_modern_map_vq_notify(struct virtio_pci_modern_device *mdev,
>  				       u16 index, resource_size_t *pa);
>  int vp_modern_probe(struct virtio_pci_modern_device *mdev);
>  void vp_modern_remove(struct virtio_pci_modern_device *mdev);
> +int vp_modern_get_queue_reset(struct virtio_pci_modern_device *mdev, u16 index);
> +void vp_modern_set_queue_reset(struct virtio_pci_modern_device *mdev, u16 index);
>  #endif
> -- 
> 2.31.0