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// SPDX-License-Identifier: GPL-2.0
/*
* Async I/O region for vfio_ccw
*
* Copyright Red Hat, Inc. 2019
*
* Author(s): Cornelia Huck <cohuck@redhat.com>
*/
#include <linux/vfio.h>
#include <linux/mdev.h>
#include "vfio_ccw_private.h"
static ssize_t vfio_ccw_async_region_read(struct vfio_ccw_private *private,
char __user *buf, size_t count,
loff_t *ppos)
{
unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
struct ccw_cmd_region *region;
int ret;
if (pos + count > sizeof(*region))
return -EINVAL;
mutex_lock(&private->io_mutex);
region = private->region[i].data;
if (copy_to_user(buf, (void *)region + pos, count))
ret = -EFAULT;
else
ret = count;
mutex_unlock(&private->io_mutex);
return ret;
}
static ssize_t vfio_ccw_async_region_write(struct vfio_ccw_private *private,
const char __user *buf, size_t count,
loff_t *ppos)
{
unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
struct ccw_cmd_region *region;
int ret;
if (pos + count > sizeof(*region))
return -EINVAL;
if (!mutex_trylock(&private->io_mutex))
return -EAGAIN;
region = private->region[i].data;
if (copy_from_user((void *)region + pos, buf, count)) {
ret = -EFAULT;
goto out_unlock;
}
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_ASYNC_REQ);
ret = region->ret_code ? region->ret_code : count;
out_unlock:
mutex_unlock(&private->io_mutex);
return ret;
}
static void vfio_ccw_async_region_release(struct vfio_ccw_private *private,
struct vfio_ccw_region *region)
{
}
static const struct vfio_ccw_regops vfio_ccw_async_region_ops = {
.read = vfio_ccw_async_region_read,
.write = vfio_ccw_async_region_write,
.release = vfio_ccw_async_region_release,
};
int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private)
{
return vfio_ccw_register_dev_region(private,
VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD,
&vfio_ccw_async_region_ops,
sizeof(struct ccw_cmd_region),
VFIO_REGION_INFO_FLAG_READ |
VFIO_REGION_INFO_FLAG_WRITE,
private->cmd_region);
}
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