drivers/s390/cio/vfio_ccw_ops.c

/*
 * Physical device callbacks for vfio_ccw
 *
 * Copyright IBM Corp. 2017
 *
 * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
 *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
 */

#include <linux/vfio.h>
#include <linux/mdev.h>

#include "vfio_ccw_private.h"

static int vfio_ccw_mdev_reset(struct mdev_device *mdev)
{
	struct vfio_ccw_private *private;
	struct subchannel *sch;
	int ret;

	private = dev_get_drvdata(mdev_parent_dev(mdev));
	if (!private)
		return -ENODEV;

	sch = private->sch;
	/*
	 * TODO:
	 * In the cureent stage, some things like "no I/O running" and "no
	 * interrupt pending" are clear, but we are not sure what other state
	 * we need to care about.
	 * There are still a lot more instructions need to be handled. We
	 * should come back here later.
	 */
	ret = vfio_ccw_sch_quiesce(sch);
	if (ret)
		return ret;

	return cio_enable_subchannel(sch, (u32)(unsigned long)sch);
}

static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
				  unsigned long action,
				  void *data)
{
	struct vfio_ccw_private *private =
		container_of(nb, struct vfio_ccw_private, nb);

	if (!private)
		return NOTIFY_STOP;

	/*
	 * Vendor drivers MUST unpin pages in response to an
	 * invalidation.
	 */
	if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP) {
		struct vfio_iommu_type1_dma_unmap *unmap = data;

		if (!cp_iova_pinned(&private->cp, unmap->iova))
			return NOTIFY_OK;

		if (vfio_ccw_mdev_reset(private->mdev))
			return NOTIFY_BAD;

		cp_free(&private->cp);
		return NOTIFY_OK;
	}

	return NOTIFY_DONE;
}

static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)
{
	return sprintf(buf, "I/O subchannel (Non-QDIO)\n");
}
MDEV_TYPE_ATTR_RO(name);

static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
			       char *buf)
{
	return sprintf(buf, "%s\n", VFIO_DEVICE_API_CCW_STRING);
}
MDEV_TYPE_ATTR_RO(device_api);

static ssize_t available_instances_show(struct kobject *kobj,
					struct device *dev, char *buf)
{
	struct vfio_ccw_private *private = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", atomic_read(&private->avail));
}
MDEV_TYPE_ATTR_RO(available_instances);

static struct attribute *mdev_types_attrs[] = {
	&mdev_type_attr_name.attr,
	&mdev_type_attr_device_api.attr,
	&mdev_type_attr_available_instances.attr,
	NULL,
};

static struct attribute_group mdev_type_group = {
	.name  = "io",
	.attrs = mdev_types_attrs,
};

struct attribute_group *mdev_type_groups[] = {
	&mdev_type_group,
	NULL,
};

static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
{
	struct vfio_ccw_private *private =
		dev_get_drvdata(mdev_parent_dev(mdev));

	if (atomic_dec_if_positive(&private->avail) < 0)
		return -EPERM;

	private->mdev = mdev;

	return 0;
}

static int vfio_ccw_mdev_remove(struct mdev_device *mdev)
{
	struct vfio_ccw_private *private =
		dev_get_drvdata(mdev_parent_dev(mdev));
	int ret;

	ret = vfio_ccw_mdev_reset(mdev);
	if (ret)
		return ret;

	private->mdev = NULL;
	atomic_inc(&private->avail);

	return 0;
}

static int vfio_ccw_mdev_open(struct mdev_device *mdev)
{
	struct vfio_ccw_private *private =
		dev_get_drvdata(mdev_parent_dev(mdev));
	unsigned long events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;

	private->nb.notifier_call = vfio_ccw_mdev_notifier;

	return vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
				      &events, &private->nb);
}

void vfio_ccw_mdev_release(struct mdev_device *mdev)
{
	struct vfio_ccw_private *private =
		dev_get_drvdata(mdev_parent_dev(mdev));

	vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
				 &private->nb);
}

static ssize_t vfio_ccw_mdev_read(struct mdev_device *mdev,
				  char __user *buf,
				  size_t count,
				  loff_t *ppos)
{
	struct vfio_ccw_private *private;
	struct ccw_io_region *region;

	if (*ppos + count > sizeof(*region))
		return -EINVAL;

	private = dev_get_drvdata(mdev_parent_dev(mdev));
	if (!private)
		return -ENODEV;

	region = &private->io_region;
	if (copy_to_user(buf, (void *)region + *ppos, count))
		return -EFAULT;

	return count;
}

static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
				   const char __user *buf,
				   size_t count,
				   loff_t *ppos)
{
	struct vfio_ccw_private *private;
	struct ccw_io_region *region;

	if (*ppos + count > sizeof(*region))
		return -EINVAL;

	private = dev_get_drvdata(mdev_parent_dev(mdev));
	if (!private)
		return -ENODEV;

	region = &private->io_region;
	if (copy_from_user((void *)region + *ppos, buf, count))
		return -EFAULT;

	region->ret_code = vfio_ccw_sch_cmd_request(private);
	if (region->ret_code != 0)
		return region->ret_code;

	return count;
}

static int vfio_ccw_mdev_get_device_info(struct vfio_device_info *info)
{
	info->flags = VFIO_DEVICE_FLAGS_CCW | VFIO_DEVICE_FLAGS_RESET;
	info->num_regions = VFIO_CCW_NUM_REGIONS;
	info->num_irqs = 0;

	return 0;
}

static int vfio_ccw_mdev_get_region_info(struct vfio_region_info *info,
					 u16 *cap_type_id,
					 void **cap_type)
{
	switch (info->index) {
	case VFIO_CCW_CONFIG_REGION_INDEX:
		info->offset = 0;
		info->size = sizeof(struct ccw_io_region);
		info->flags = VFIO_REGION_INFO_FLAG_READ
			      | VFIO_REGION_INFO_FLAG_WRITE;
		return 0;
	default:
		return -EINVAL;
	}
}

static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
				   unsigned int cmd,
				   unsigned long arg)
{
	int ret = 0;
	unsigned long minsz;

	switch (cmd) {
	case VFIO_DEVICE_GET_INFO:
	{
		struct vfio_device_info info;

		minsz = offsetofend(struct vfio_device_info, num_irqs);

		if (copy_from_user(&info, (void __user *)arg, minsz))
			return -EFAULT;

		if (info.argsz < minsz)
			return -EINVAL;

		ret = vfio_ccw_mdev_get_device_info(&info);
		if (ret)
			return ret;

		return copy_to_user((void __user *)arg, &info, minsz);
	}
	case VFIO_DEVICE_GET_REGION_INFO:
	{
		struct vfio_region_info info;
		u16 cap_type_id = 0;
		void *cap_type = NULL;

		minsz = offsetofend(struct vfio_region_info, offset);

		if (copy_from_user(&info, (void __user *)arg, minsz))
			return -EFAULT;

		if (info.argsz < minsz)
			return -EINVAL;

		ret = vfio_ccw_mdev_get_region_info(&info, &cap_type_id,
						    &cap_type);
		if (ret)
			return ret;

		return copy_to_user((void __user *)arg, &info, minsz);
	}
	case VFIO_DEVICE_RESET:
		return vfio_ccw_mdev_reset(mdev);
	default:
		return -ENOTTY;
	}
}

static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
	.owner			= THIS_MODULE,
	.supported_type_groups  = mdev_type_groups,
	.create			= vfio_ccw_mdev_create,
	.remove			= vfio_ccw_mdev_remove,
	.open			= vfio_ccw_mdev_open,
	.release		= vfio_ccw_mdev_release,
	.read			= vfio_ccw_mdev_read,
	.write			= vfio_ccw_mdev_write,
	.ioctl			= vfio_ccw_mdev_ioctl,
};

int vfio_ccw_mdev_reg(struct subchannel *sch)
{
	return mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);
}

void vfio_ccw_mdev_unreg(struct subchannel *sch)
{
	mdev_unregister_device(&sch->dev);
}