Re: [PATCH v4 11/16] vfio: ccw: realize VFIO_DEVICE_G(S)ET_IRQ_INFO ioctls

Alex Williamson
2017-03-21T18:47:24Z

On Fri, 17 Mar 2017 04:17:38 +0100
Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> wrote:

> Realize VFIO_DEVICE_GET_IRQ_INFO ioctl to retrieve
> VFIO_CCW_IO_IRQ information.
>
> Realize VFIO_DEVICE_SET_IRQS ioctl to set an eventfd fd for
> VFIO_CCW_IO_IRQ. Once a write operation to the ccw_io_region
> was performed, trigger a signal on this fd.
>
> Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
> Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
> ---
> drivers/s390/cio/vfio_ccw_ops.c | 123 +++++++++++++++++++++++++++++++++++-
> drivers/s390/cio/vfio_ccw_private.h | 4 ++
> include/uapi/linux/vfio.h | 10 ++-
> 3 files changed, 134 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
> index 125818c..1294c53 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -202,6 +202,9 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
> if (region->ret_code != 0)
> return region->ret_code;
>
> + if (private->io_trigger)
> + eventfd_signal(private->io_trigger, 1);
> +
> return count;
> }
>
> @@ -209,7 +212,7 @@ 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;
> + info->num_irqs = VFIO_CCW_NUM_IRQS;
>
> return 0;
> }
> @@ -230,6 +233,83 @@ static int vfio_ccw_mdev_get_region_info(struct vfio_region_info *info,
> }
> }
>
> +int vfio_ccw_mdev_get_irq_info(struct vfio_irq_info *info)
> +{
> + if (info->index != VFIO_CCW_IO_IRQ_INDEX)
> + return -EINVAL;
> +
> + info->count = 1;
> + info->flags = VFIO_IRQ_INFO_EVENTFD;
> +
> + return 0;
> +}
> +
> +static int vfio_ccw_mdev_set_irqs(struct mdev_device *mdev,
> + uint32_t flags,
> + void __user *data)
> +{
> + struct vfio_ccw_private *private;
> + struct eventfd_ctx **ctx;
> +
> + if (!(flags & VFIO_IRQ_SET_ACTION_TRIGGER))
> + return -EINVAL;
> +
> + private = dev_get_drvdata(mdev_parent_dev(mdev));
> + if (!private)
> + return -ENODEV;
> +
> + ctx = &private->io_trigger;
> +
> + switch (flags & VFIO_IRQ_SET_DATA_TYPE_MASK) {
> + case VFIO_IRQ_SET_DATA_NONE:
> + {
> + if (*ctx)
> + eventfd_signal(*ctx, 1);
> + return 0;
> + }
> + case VFIO_IRQ_SET_DATA_BOOL:
> + {
> + uint8_t trigger;
> +
> + if (get_user(trigger, (uint8_t __user *)data))
> + return -EFAULT;
> +
> + if (trigger && *ctx)
> + eventfd_signal(*ctx, 1);
> + return 0;
> + }
> + case VFIO_IRQ_SET_DATA_EVENTFD:
> + {
> + int32_t fd;
> +
> + if (get_user(fd, (int32_t __user *)data))
> + return -EFAULT;
> +
> + if (fd == -1) {
> + if (*ctx)
> + eventfd_ctx_put(*ctx);
> + *ctx = NULL;
> + } else if (fd >= 0) {
> + struct eventfd_ctx *efdctx;
> +
> + efdctx = eventfd_ctx_fdget(fd);
> + if (IS_ERR(efdctx))
> + return PTR_ERR(efdctx);
> +
> + if (*ctx)
> + eventfd_ctx_put(*ctx);
> +
> + *ctx = efdctx;
> + } else
> + return -EINVAL;
> +
> + return 0;
> + }
> + default:
> + return -EINVAL;
> + }
> +}
> +
> static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
> unsigned int cmd,
> unsigned long arg)
> @@ -277,6 +357,47 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
>
> return copy_to_user((void __user *)arg, &info, minsz);
> }
> + case VFIO_DEVICE_GET_IRQ_INFO:
> + {
> + struct vfio_irq_info info;
> +
> + minsz = offsetofend(struct vfio_irq_info, count);
> +
> + if (copy_from_user(&info, (void __user *)arg, minsz))
> + return -EFAULT;
> +
> + if (info.argsz < minsz || info.index >= VFIO_CCW_NUM_IRQS)
> + return -EINVAL;
> +
> + ret = vfio_ccw_mdev_get_irq_info(&info);
> + if (ret)
> + return ret;
> +
> + if (info.count == -1)
> + return -EINVAL;
> +
> + return copy_to_user((void __user *)arg, &info, minsz);
> + }
> + case VFIO_DEVICE_SET_IRQS:
> + {
> + struct vfio_irq_set hdr;
> + size_t data_size;
> + void __user *data;
> +
> + minsz = offsetofend(struct vfio_irq_set, count);
> +
> + if (copy_from_user(&hdr, (void __user *)arg, minsz))
> + return -EFAULT;
> +
> + ret = vfio_set_irqs_validate_and_prepare(&hdr, 1,
> + VFIO_CCW_NUM_IRQS,
> + &data_size);
> + if (ret)
> + return ret;
> +
> + data = (void __user *)(arg + minsz);
> + return vfio_ccw_mdev_set_irqs(mdev, hdr.flags, data);
> + }
> case VFIO_DEVICE_RESET:
> return vfio_ccw_mdev_reset(mdev);
> default:
> diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
> index 79e5337..dddab52 100644
> --- a/drivers/s390/cio/vfio_ccw_private.h
> +++ b/drivers/s390/cio/vfio_ccw_private.h
> @@ -11,6 +11,7 @@
> #define _VFIO_CCW_PRIVATE_H_
>
> #include <linux/completion.h>
> +#include <linux/eventfd.h>
> #include <linux/vfio_ccw.h>
>
> #include "css.h"
> @@ -29,6 +30,7 @@
> * @cp: channel program for the current I/O operation
> * @irb: irb info received from interrupt
> * @scsw: scsw info
> + * @io_trigger: eventfd ctx for signaling userspace I/O results
> */
> struct vfio_ccw_private {
> struct subchannel *sch;
> @@ -43,6 +45,8 @@ struct vfio_ccw_private {
> struct channel_program cp;
> struct irb irb;
> union scsw scsw;
> +
> + struct eventfd_ctx *io_trigger;
> } __aligned(8);
>
> extern int vfio_ccw_mdev_reg(struct subchannel *sch);
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 3fd70ff..ae46105 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -449,8 +449,9 @@ enum {
> };
>
> /*
> - * The vfio-ccw bus driver makes use of the following fixed region.
> - * Unimplemented regions return a size of zero.
> + * The vfio-ccw bus driver makes use of the following fixed region and
> + * IRQ index mapping. Unimplemented regions return a size of zero.
> + * Unimplemented IRQ types return a count of zero.
> */
>
> enum {
> @@ -458,6 +459,11 @@ enum {
> VFIO_CCW_NUM_REGIONS
> };
>
> +enum {
> + VFIO_CCW_IO_IRQ_INDEX,
> + VFIO_CCW_NUM_IRQS
> +};
> +
> /**
> * VFIO_DEVICE_GET_PCI_HOT_RESET_INFO - _IORW(VFIO_TYPE, VFIO_BASE + 12,
> * struct vfio_pci_hot_reset_info)

Acked-by: Alex Williamson <alex.williamson@redhat.com>