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

From: "Michael S. Tsirkin" <mst@redhat.com>
To: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: virtualization@lists.linux-foundation.org,
	Richard Weinberger <richard@nod.at>,
	Anton Ivanov <anton.ivanov@cambridgegreys.com>,
	Johannes Berg <johannes@sipsolutions.net>,
	Jason Wang <jasowang@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Hans de Goede <hdegoede@redhat.com>,
	Mark Gross <markgross@kernel.org>,
	Vadim Pasternak <vadimp@nvidia.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Cornelia Huck <cohuck@redhat.com>,
	Halil Pasic <pasic@linux.ibm.com>,
	Eric Farman <farman@linux.ibm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
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	Sven Schnelle <svens@linux.ibm.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
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	John Fastabend <john.fastabend@gmail.com>,
	Vincent Whitchurch <vincent.whitchurch@axis.com>,
	linux-um@lists.infradead.org, netdev@vger.kernel.org,
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	kangjie.xu@linux.alibaba.com
Subject: Re: [PATCH v14 30/42] virtio_pci: introduce helper to get/set queue reset
Date: Mon, 15 Aug 2022 02:07:05 -0400	[thread overview]
Message-ID: <20220815020548-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20220801063902.129329-31-xuanzhuo@linux.alibaba.com>

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