On Fri, 17 Feb 2017 09:29:31 +0100
Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx> wrote:
> To provide user-space a set of interfaces to:
> 1. pass in a ccw program to perform an I/O operation.
> 2. read back I/O results of the completed I/O operations.
> We introduce an MMIO region for the vfio-ccw device here.
>
> This region is defined to content:
> 1. areas to store arguments that an ssch required.
> 2. areas to store the I/O results.
>
> Using pwrite/pread to the device on this region, a user-space program
> could write/read data to/from the vfio-ccw device.
>
> Signed-off-by: Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx>
> Reviewed-by: Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx>
> ---
> arch/s390/include/uapi/asm/Kbuild | 1 +
> drivers/s390/cio/vfio_ccw_ops.c | 47 +++++++++++++++++++++++++++++++++++++
> drivers/s390/cio/vfio_ccw_private.h | 4 ++++
> include/uapi/linux/vfio_ccw.h | 24 +++++++++++++++++++
> 4 files changed, 76 insertions(+)
> create mode 100644 include/uapi/linux/vfio_ccw.h
>
> diff --git a/arch/s390/include/uapi/asm/Kbuild b/arch/s390/include/uapi/asm/Kbuild
> index bf736e7..fdb9529 100644
> --- a/arch/s390/include/uapi/asm/Kbuild
> +++ b/arch/s390/include/uapi/asm/Kbuild
> @@ -52,3 +52,4 @@ header-y += unistd.h
> header-y += virtio-ccw.h
> header-y += vtoc.h
> header-y += zcrypt.h
> +header-y += vfio_ccw.h
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
> index b8a2fed..6c06805 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -127,6 +127,51 @@ void vfio_ccw_mdev_release(struct mdev_device *mdev)
> &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;
Couldn't this wrap-around and still satisfy this test?
> +
> + 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;
Same here
> +
> + 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 = 0;
> +
> + return count;
> +}
> +
> static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
> .owner = THIS_MODULE,
> .supported_type_groups = mdev_type_groups,
> @@ -134,6 +179,8 @@ static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
> .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,
> };
>
> int vfio_ccw_mdev_reg(struct subchannel *sch)
> diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
> index 5afb3ba..359e96b 100644
> --- a/drivers/s390/cio/vfio_ccw_private.h
> +++ b/drivers/s390/cio/vfio_ccw_private.h
> @@ -10,6 +10,8 @@
> #ifndef _VFIO_CCW_PRIVATE_H_
> #define _VFIO_CCW_PRIVATE_H_
>
> +#include <linux/vfio_ccw.h>
> +
> #include "css.h"
>
> /**
> @@ -19,6 +21,7 @@
> * @avail: available for creating a mediated device
> * @mdev: pointer to the mediated device
> * @nb: notifier for vfio events
> + * @io_region: MMIO region to input/output I/O arguments/results
> */
> struct vfio_ccw_private {
> struct subchannel *sch;
> @@ -26,6 +29,7 @@ struct vfio_ccw_private {
> atomic_t avail;
> struct mdev_device *mdev;
> struct notifier_block nb;
> + struct ccw_io_region io_region;
> } __aligned(8);
>
> extern int vfio_ccw_mdev_reg(struct subchannel *sch);
> diff --git a/include/uapi/linux/vfio_ccw.h b/include/uapi/linux/vfio_ccw.h
> new file mode 100644
> index 0000000..34a7f6f
> --- /dev/null
> +++ b/include/uapi/linux/vfio_ccw.h
> @@ -0,0 +1,24 @@
> +/*
> + * Interfaces for vfio-ccw
> + *
> + * Copyright IBM Corp. 2017
> + *
> + * Author(s): Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx>
> + */
> +
> +#ifndef _VFIO_CCW_H_
> +#define _VFIO_CCW_H_
> +
> +#include <linux/types.h>
> +
> +struct ccw_io_region {
> +#define ORB_AREA_SIZE 12
> + __u8 orb_area[ORB_AREA_SIZE];
> +#define SCSW_AREA_SIZE 12
> + __u8 scsw_area[SCSW_AREA_SIZE];
> +#define IRB_AREA_SIZE 96
> + __u8 irb_area[IRB_AREA_SIZE];
> + __u32 ret_code;
> +} __packed;
> +
> +#endif
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