Re: [PATCH V2 01/14] virtio-pci: do not access iomem via virtio_pci_device directly

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Nov 26, 2020 at 05:25:51PM +0800, Jason Wang wrote:
> Instead of accessing iomem via virito_pci_device directly. Add an
> indirect level

well this patch does not add any indirection it's just refactoring.
which is ok of course let's just say it as is.

> to ease the life of splitting out modern virito-pci

typo

> logic.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  drivers/virtio/virtio_pci_modern.c | 76 ++++++++++++++++++------------
>  1 file changed, 46 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index 3d6ae5a5e252..df1481fd400c 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -141,12 +141,13 @@ static void __iomem *map_capability(struct pci_dev *dev, int off,
>  static u64 vp_get_features(struct virtio_device *vdev)
>  {
>  	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
>  	u64 features;
>  
> -	vp_iowrite32(0, &vp_dev->common->device_feature_select);
> -	features = vp_ioread32(&vp_dev->common->device_feature);
> -	vp_iowrite32(1, &vp_dev->common->device_feature_select);
> -	features |= ((u64)vp_ioread32(&vp_dev->common->device_feature) << 32);
> +	vp_iowrite32(0, &cfg->device_feature_select);
> +	features = vp_ioread32(&cfg->device_feature);
> +	vp_iowrite32(1, &cfg->device_feature_select);
> +	features |= ((u64)vp_ioread32(&cfg->device_feature) << 32);
>  
>  	return features;
>  }
> @@ -165,6 +166,7 @@ static void vp_transport_features(struct virtio_device *vdev, u64 features)
>  static int vp_finalize_features(struct virtio_device *vdev)
>  {
>  	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
>  	u64 features = vdev->features;
>  
>  	/* Give virtio_ring a chance to accept features. */
> @@ -179,10 +181,10 @@ static int vp_finalize_features(struct virtio_device *vdev)
>  		return -EINVAL;
>  	}
>  
> -	vp_iowrite32(0, &vp_dev->common->guest_feature_select);
> -	vp_iowrite32((u32)vdev->features, &vp_dev->common->guest_feature);
> -	vp_iowrite32(1, &vp_dev->common->guest_feature_select);
> -	vp_iowrite32(vdev->features >> 32, &vp_dev->common->guest_feature);
> +	vp_iowrite32(0, &cfg->guest_feature_select);
> +	vp_iowrite32((u32)vdev->features, &cfg->guest_feature);
> +	vp_iowrite32(1, &cfg->guest_feature_select);
> +	vp_iowrite32(vdev->features >> 32, &cfg->guest_feature);
>  
>  	return 0;
>  }
> @@ -192,6 +194,7 @@ static void vp_get(struct virtio_device *vdev, unsigned offset,
>  		   void *buf, unsigned len)
>  {
>  	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +	void __iomem *device = vp_dev->device;
>  	u8 b;
>  	__le16 w;
>  	__le32 l;
> @@ -200,21 +203,21 @@ static void vp_get(struct virtio_device *vdev, unsigned offset,
>  
>  	switch (len) {
>  	case 1:
> -		b = ioread8(vp_dev->device + offset);
> +		b = ioread8(device + offset);
>  		memcpy(buf, &b, sizeof b);
>  		break;
>  	case 2:
> -		w = cpu_to_le16(ioread16(vp_dev->device + offset));
> +		w = cpu_to_le16(ioread16(device + offset));
>  		memcpy(buf, &w, sizeof w);
>  		break;
>  	case 4:
> -		l = cpu_to_le32(ioread32(vp_dev->device + offset));
> +		l = cpu_to_le32(ioread32(device + offset));
>  		memcpy(buf, &l, sizeof l);
>  		break;
>  	case 8:
> -		l = cpu_to_le32(ioread32(vp_dev->device + offset));
> +		l = cpu_to_le32(ioread32(device + offset));
>  		memcpy(buf, &l, sizeof l);
> -		l = cpu_to_le32(ioread32(vp_dev->device + offset + sizeof l));
> +		l = cpu_to_le32(ioread32(device + offset + sizeof l));
>  		memcpy(buf + sizeof l, &l, sizeof l);
>  		break;
>  	default:
> @@ -228,6 +231,7 @@ static void vp_set(struct virtio_device *vdev, unsigned offset,
>  		   const void *buf, unsigned len)
>  {
>  	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +	void __iomem *device = vp_dev->device;
>  	u8 b;
>  	__le16 w;
>  	__le32 l;
> @@ -237,21 +241,21 @@ static void vp_set(struct virtio_device *vdev, unsigned offset,
>  	switch (len) {
>  	case 1:
>  		memcpy(&b, buf, sizeof b);
> -		iowrite8(b, vp_dev->device + offset);
> +		iowrite8(b, device + offset);
>  		break;
>  	case 2:
>  		memcpy(&w, buf, sizeof w);
> -		iowrite16(le16_to_cpu(w), vp_dev->device + offset);
> +		iowrite16(le16_to_cpu(w), device + offset);
>  		break;
>  	case 4:
>  		memcpy(&l, buf, sizeof l);
> -		iowrite32(le32_to_cpu(l), vp_dev->device + offset);
> +		iowrite32(le32_to_cpu(l), device + offset);
>  		break;
>  	case 8:
>  		memcpy(&l, buf, sizeof l);
> -		iowrite32(le32_to_cpu(l), vp_dev->device + offset);
> +		iowrite32(le32_to_cpu(l), device + offset);
>  		memcpy(&l, buf + sizeof l, sizeof l);
> -		iowrite32(le32_to_cpu(l), vp_dev->device + offset + sizeof l);
> +		iowrite32(le32_to_cpu(l), device + offset + sizeof l);
>  		break;
>  	default:
>  		BUG();
> @@ -261,35 +265,43 @@ static void vp_set(struct virtio_device *vdev, unsigned offset,
>  static u32 vp_generation(struct virtio_device *vdev)
>  {
>  	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> -	return vp_ioread8(&vp_dev->common->config_generation);
> +	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
> +
> +	return vp_ioread8(&cfg->config_generation);
>  }
>  
>  /* config->{get,set}_status() implementations */
>  static u8 vp_get_status(struct virtio_device *vdev)
>  {
>  	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> -	return vp_ioread8(&vp_dev->common->device_status);
> +	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
> +
> +	return vp_ioread8(&cfg->device_status);
>  }
>  
>  static void vp_set_status(struct virtio_device *vdev, u8 status)
>  {
>  	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
> +
>  	/* We should never be setting status to 0. */
>  	BUG_ON(status == 0);
> -	vp_iowrite8(status, &vp_dev->common->device_status);
> +	vp_iowrite8(status, &cfg->device_status);
>  }
>  
>  static void vp_reset(struct virtio_device *vdev)
>  {
>  	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
> +
>  	/* 0 status means a reset. */
> -	vp_iowrite8(0, &vp_dev->common->device_status);
> +	vp_iowrite8(0, &cfg->device_status);
>  	/* After writing 0 to device_status, the driver MUST wait for a read of
>  	 * device_status to return 0 before reinitializing the device.
>  	 * This will flush out the status write, and flush in device writes,
>  	 * including MSI-X interrupts, if any.
>  	 */
> -	while (vp_ioread8(&vp_dev->common->device_status))
> +	while (vp_ioread8(&cfg->device_status))
>  		msleep(1);
>  	/* Flush pending VQ/configuration callbacks. */
>  	vp_synchronize_vectors(vdev);
> @@ -297,11 +309,13 @@ static void vp_reset(struct virtio_device *vdev)
>  
>  static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
>  {
> +	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
> +
>  	/* Setup the vector used for configuration events */
> -	vp_iowrite16(vector, &vp_dev->common->msix_config);
> +	vp_iowrite16(vector, &cfg->msix_config);
>  	/* Verify we had enough resources to assign the vector */
>  	/* Will also flush the write out to device */
> -	return vp_ioread16(&vp_dev->common->msix_config);
> +	return vp_ioread16(&cfg->msix_config);
>  }
>  
>  static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> @@ -407,6 +421,7 @@ static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
>  			      struct irq_affinity *desc)
>  {
>  	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
>  	struct virtqueue *vq;
>  	int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names, ctx, desc);
>  
> @@ -417,8 +432,8 @@ static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
>  	 * this, there's no way to go back except reset.
>  	 */
>  	list_for_each_entry(vq, &vdev->vqs, list) {
> -		vp_iowrite16(vq->index, &vp_dev->common->queue_select);
> -		vp_iowrite16(1, &vp_dev->common->queue_enable);
> +		vp_iowrite16(vq->index, &cfg->queue_select);
> +		vp_iowrite16(1, &cfg->queue_enable);
>  	}
>  
>  	return 0;
> @@ -428,14 +443,15 @@ static void del_vq(struct virtio_pci_vq_info *info)
>  {
>  	struct virtqueue *vq = info->vq;
>  	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
> +	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
>  
> -	vp_iowrite16(vq->index, &vp_dev->common->queue_select);
> +	vp_iowrite16(vq->index, &cfg->queue_select);
>  
>  	if (vp_dev->msix_enabled) {
>  		vp_iowrite16(VIRTIO_MSI_NO_VECTOR,
> -			     &vp_dev->common->queue_msix_vector);
> +			     &cfg->queue_msix_vector);
>  		/* Flush the write out to device */
> -		vp_ioread16(&vp_dev->common->queue_msix_vector);
> +		vp_ioread16(&cfg->queue_msix_vector);
>  	}
>  
>  	if (!vp_dev->notify_base)
> -- 
> 2.25.1

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