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

From: Michael S. Tsirkin
Date: Thu Nov 26 2020 - 08:47:01 EST

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In reply to: Jason Wang: "[PATCH V2 01/14] virtio-pci: do not access iomem via virtio_pci_device directly"
Next in thread: Jason Wang: "Re: [PATCH V2 01/14] virtio-pci: do not access iomem via virtio_pci_device directly"
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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@xxxxxxxxxx>
> ---
> 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

Next message: SeongJae Park: "Re: [PATCH v22 10/18] mm/damon: Implement a debugfs-based user space interface"
Previous message: James Clark: "Re: [PATCH v5 01/12] perf tools: Improve topology test"
In reply to: Jason Wang: "[PATCH V2 01/14] virtio-pci: do not access iomem via virtio_pci_device directly"
Next in thread: Jason Wang: "Re: [PATCH V2 01/14] virtio-pci: do not access iomem via virtio_pci_device directly"
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