On Fri, 2021-10-01 at 14:52 -0300, Jason Gunthorpe wrote:
> This is a more complicated conversion because vfio_ccw is sharing the
> vfio_device between both the mdev_device, its vfio_device and the
> css_driver.
>
> The mdev is a singleton, and the reason for this sharing is so the
> extra
> css_driver function callbacks to be delivered to the vfio_device
> implementation.
>
> This keeps things as they are, with the css_driver allocating the
> singleton, not the mdev_driver. Following patches work to clean this
> further.
>
> Embed the vfio_device in the vfio_ccw_private and instantiate it as a
> vfio_device when the mdev probes. The drvdata of both the css_device
> and
> the mdev_device point at the private, and container_of is used to get
> it
> back from the vfio_device.
>
> Signed-off-by: Jason Gunthorpe <j...@nvidia.com>
Reviewed-by: Eric Farman <far...@linux.ibm.com>
Worth noting that this particular patch depends on Alex' vfio/next
branch, which defines vfio_register_emulated_iommu_dev() and is used
below. That is alluded to in the cover letter, but of course I forgot
that point when going through the mbox.
> ---
> drivers/s390/cio/vfio_ccw_drv.c | 21 ++++--
> drivers/s390/cio/vfio_ccw_ops.c | 107 +++++++++++++++++---------
> --
> drivers/s390/cio/vfio_ccw_private.h | 5 ++
> 3 files changed, 85 insertions(+), 48 deletions(-)
>
> diff --git a/drivers/s390/cio/vfio_ccw_drv.c
> b/drivers/s390/cio/vfio_ccw_drv.c
> index e32678a71644fb..0407427770955d 100644
> --- a/drivers/s390/cio/vfio_ccw_drv.c
> +++ b/drivers/s390/cio/vfio_ccw_drv.c
> @@ -468,7 +468,7 @@ static int __init vfio_ccw_sch_init(void)
> vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
> if (!vfio_ccw_work_q) {
> ret = -ENOMEM;
> - goto out_err;
> + goto out_regions;
> }
>
> vfio_ccw_io_region =
> kmem_cache_create_usercopy("vfio_ccw_io_region",
> @@ -477,7 +477,7 @@ static int __init vfio_ccw_sch_init(void)
> sizeof(struct ccw_io_region),
> NULL);
> if (!vfio_ccw_io_region) {
> ret = -ENOMEM;
> - goto out_err;
> + goto out_regions;
> }
>
> vfio_ccw_cmd_region =
> kmem_cache_create_usercopy("vfio_ccw_cmd_region",
> @@ -486,7 +486,7 @@ static int __init vfio_ccw_sch_init(void)
> sizeof(struct ccw_cmd_region),
> NULL);
> if (!vfio_ccw_cmd_region) {
> ret = -ENOMEM;
> - goto out_err;
> + goto out_regions;
> }
>
> vfio_ccw_schib_region =
> kmem_cache_create_usercopy("vfio_ccw_schib_region",
> @@ -496,7 +496,7 @@ static int __init vfio_ccw_sch_init(void)
>
> if (!vfio_ccw_schib_region) {
> ret = -ENOMEM;
> - goto out_err;
> + goto out_regions;
> }
>
> vfio_ccw_crw_region =
> kmem_cache_create_usercopy("vfio_ccw_crw_region",
> @@ -506,19 +506,25 @@ static int __init vfio_ccw_sch_init(void)
>
> if (!vfio_ccw_crw_region) {
> ret = -ENOMEM;
> - goto out_err;
> + goto out_regions;
> }
>
> + ret = mdev_register_driver(&vfio_ccw_mdev_driver);
> + if (ret)
> + goto out_regions;
> +
> isc_register(VFIO_CCW_ISC);
> ret = css_driver_register(&vfio_ccw_sch_driver);
> if (ret) {
> isc_unregister(VFIO_CCW_ISC);
> - goto out_err;
> + goto out_driver;
> }
>
> return ret;
>
> -out_err:
> +out_driver:
> + mdev_unregister_driver(&vfio_ccw_mdev_driver);
> +out_regions:
> vfio_ccw_destroy_regions();
> destroy_workqueue(vfio_ccw_work_q);
> vfio_ccw_debug_exit();
> @@ -528,6 +534,7 @@ static int __init vfio_ccw_sch_init(void)
> static void __exit vfio_ccw_sch_exit(void)
> {
> css_driver_unregister(&vfio_ccw_sch_driver);
> + mdev_unregister_driver(&vfio_ccw_mdev_driver);
> isc_unregister(VFIO_CCW_ISC);
> vfio_ccw_destroy_regions();
> destroy_workqueue(vfio_ccw_work_q);
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c
> b/drivers/s390/cio/vfio_ccw_ops.c
> index 1edbea9de0ec42..d8589afac272f1 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -17,6 +17,8 @@
>
> #include "vfio_ccw_private.h"
>
> +static const struct vfio_device_ops vfio_ccw_dev_ops;
> +
> static int vfio_ccw_mdev_reset(struct vfio_ccw_private *private)
> {
> struct subchannel *sch;
> @@ -111,10 +113,10 @@ static struct attribute_group
> *mdev_type_groups[] = {
> NULL,
> };
>
> -static int vfio_ccw_mdev_create(struct mdev_device *mdev)
> +static int vfio_ccw_mdev_probe(struct mdev_device *mdev)
> {
> - struct vfio_ccw_private *private =
> - dev_get_drvdata(mdev_parent_dev(mdev));
> + struct vfio_ccw_private *private = dev_get_drvdata(mdev-
> >dev.parent);
> + int ret;
>
> if (private->state == VFIO_CCW_STATE_NOT_OPER)
> return -ENODEV;
> @@ -122,6 +124,10 @@ static int vfio_ccw_mdev_create(struct
> mdev_device *mdev)
> if (atomic_dec_if_positive(&private->avail) < 0)
> return -EPERM;
>
> + memset(&private->vdev, 0, sizeof(private->vdev));
> + vfio_init_group_dev(&private->vdev, &mdev->dev,
> + &vfio_ccw_dev_ops);
> +
> private->mdev = mdev;
> private->state = VFIO_CCW_STATE_IDLE;
>
> @@ -130,19 +136,31 @@ static int vfio_ccw_mdev_create(struct
> mdev_device *mdev)
> private->sch->schid.ssid,
> private->sch->schid.sch_no);
>
> + ret = vfio_register_emulated_iommu_dev(&private->vdev);
> + if (ret)
> + goto err_atomic;
> + dev_set_drvdata(&mdev->dev, private);
> return 0;
> +
> +err_atomic:
> + vfio_uninit_group_dev(&private->vdev);
> + atomic_inc(&private->avail);
> + private->mdev = NULL;
> + private->state = VFIO_CCW_STATE_IDLE;
> + return ret;
> }
>
> -static int vfio_ccw_mdev_remove(struct mdev_device *mdev)
> +static void vfio_ccw_mdev_remove(struct mdev_device *mdev)
> {
> - struct vfio_ccw_private *private =
> - dev_get_drvdata(mdev_parent_dev(mdev));
> + struct vfio_ccw_private *private = dev_get_drvdata(mdev-
> >dev.parent);
>
> VFIO_CCW_MSG_EVENT(2, "mdev %pUl, sch %x.%x.%04x: remove\n",
> mdev_uuid(mdev), private->sch->schid.cssid,
> private->sch->schid.ssid,
> private->sch->schid.sch_no);
>
> + vfio_unregister_group_dev(&private->vdev);
> +
> if ((private->state != VFIO_CCW_STATE_NOT_OPER) &&
> (private->state != VFIO_CCW_STATE_STANDBY)) {
> if (!vfio_ccw_sch_quiesce(private->sch))
> @@ -150,23 +168,22 @@ static int vfio_ccw_mdev_remove(struct
> mdev_device *mdev)
> /* The state will be NOT_OPER on error. */
> }
>
> + vfio_uninit_group_dev(&private->vdev);
> cp_free(&private->cp);
> private->mdev = NULL;
> atomic_inc(&private->avail);
> -
> - return 0;
> }
>
> -static int vfio_ccw_mdev_open_device(struct mdev_device *mdev)
> +static int vfio_ccw_mdev_open_device(struct vfio_device *vdev)
> {
> struct vfio_ccw_private *private =
> - dev_get_drvdata(mdev_parent_dev(mdev));
> + container_of(vdev, struct vfio_ccw_private, vdev);
> unsigned long events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
> int ret;
>
> private->nb.notifier_call = vfio_ccw_mdev_notifier;
>
> - ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
> + ret = vfio_register_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
> &events, &private->nb);
> if (ret)
> return ret;
> @@ -187,15 +204,15 @@ static int vfio_ccw_mdev_open_device(struct
> mdev_device *mdev)
>
> out_unregister:
> vfio_ccw_unregister_dev_regions(private);
> - vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
> + vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
> &private->nb);
> return ret;
> }
>
> -static void vfio_ccw_mdev_close_device(struct mdev_device *mdev)
> +static void vfio_ccw_mdev_close_device(struct vfio_device *vdev)
> {
> struct vfio_ccw_private *private =
> - dev_get_drvdata(mdev_parent_dev(mdev));
> + container_of(vdev, struct vfio_ccw_private, vdev);
>
> if ((private->state != VFIO_CCW_STATE_NOT_OPER) &&
> (private->state != VFIO_CCW_STATE_STANDBY)) {
> @@ -206,8 +223,7 @@ static void vfio_ccw_mdev_close_device(struct
> mdev_device *mdev)
>
> cp_free(&private->cp);
> vfio_ccw_unregister_dev_regions(private);
> - vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
> - &private->nb);
> + vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
> &private->nb);
> }
>
> static ssize_t vfio_ccw_mdev_read_io_region(struct vfio_ccw_private
> *private,
> @@ -231,15 +247,14 @@ static ssize_t
> vfio_ccw_mdev_read_io_region(struct vfio_ccw_private *private,
> return ret;
> }
>
> -static ssize_t vfio_ccw_mdev_read(struct mdev_device *mdev,
> +static ssize_t vfio_ccw_mdev_read(struct vfio_device *vdev,
> char __user *buf,
> size_t count,
> loff_t *ppos)
> {
> + struct vfio_ccw_private *private =
> + container_of(vdev, struct vfio_ccw_private, vdev);
> unsigned int index = VFIO_CCW_OFFSET_TO_INDEX(*ppos);
> - struct vfio_ccw_private *private;
> -
> - private = dev_get_drvdata(mdev_parent_dev(mdev));
>
> if (index >= VFIO_CCW_NUM_REGIONS + private->num_regions)
> return -EINVAL;
> @@ -284,15 +299,14 @@ static ssize_t
> vfio_ccw_mdev_write_io_region(struct vfio_ccw_private *private,
> return ret;
> }
>
> -static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
> +static ssize_t vfio_ccw_mdev_write(struct vfio_device *vdev,
> const char __user *buf,
> size_t count,
> loff_t *ppos)
> {
> + struct vfio_ccw_private *private =
> + container_of(vdev, struct vfio_ccw_private, vdev);
> unsigned int index = VFIO_CCW_OFFSET_TO_INDEX(*ppos);
> - struct vfio_ccw_private *private;
> -
> - private = dev_get_drvdata(mdev_parent_dev(mdev));
>
> if (index >= VFIO_CCW_NUM_REGIONS + private->num_regions)
> return -EINVAL;
> @@ -510,12 +524,12 @@ void vfio_ccw_unregister_dev_regions(struct
> vfio_ccw_private *private)
> private->region = NULL;
> }
>
> -static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
> +static ssize_t vfio_ccw_mdev_ioctl(struct vfio_device *vdev,
> unsigned int cmd,
> unsigned long arg)
> {
> struct vfio_ccw_private *private =
> - dev_get_drvdata(mdev_parent_dev(mdev));
> + container_of(vdev, struct vfio_ccw_private, vdev);
> int ret = 0;
> unsigned long minsz;
>
> @@ -606,37 +620,48 @@ static ssize_t vfio_ccw_mdev_ioctl(struct
> mdev_device *mdev,
> }
>
> /* Request removal of the device*/
> -static void vfio_ccw_mdev_request(struct mdev_device *mdev, unsigned
> int count)
> +static void vfio_ccw_mdev_request(struct vfio_device *vdev, unsigned
> int count)
> {
> - struct vfio_ccw_private *private =
> dev_get_drvdata(mdev_parent_dev(mdev));
> -
> - if (!private)
> - return;
> + struct vfio_ccw_private *private =
> + container_of(vdev, struct vfio_ccw_private, vdev);
> + struct device *dev = vdev->dev;
>
> if (private->req_trigger) {
> if (!(count % 10))
> - dev_notice_ratelimited(mdev_dev(private->mdev),
> + dev_notice_ratelimited(dev,
> "Relaying device request
> to user (#%u)\n",
> count);
>
> eventfd_signal(private->req_trigger, 1);
> } else if (count == 0) {
> - dev_notice(mdev_dev(private->mdev),
> + dev_notice(dev,
> "No device request channel registered,
> blocked until released by user\n");
> }
> }
>
> +static const struct vfio_device_ops vfio_ccw_dev_ops = {
> + .open_device = vfio_ccw_mdev_open_device,
> + .close_device = vfio_ccw_mdev_close_device,
> + .read = vfio_ccw_mdev_read,
> + .write = vfio_ccw_mdev_write,
> + .ioctl = vfio_ccw_mdev_ioctl,
> + .request = vfio_ccw_mdev_request,
> +};
> +
> +struct mdev_driver vfio_ccw_mdev_driver = {
> + .driver = {
> + .name = "vfio_ccw_mdev",
> + .owner = THIS_MODULE,
> + .mod_name = KBUILD_MODNAME,
> + },
> + .probe = vfio_ccw_mdev_probe,
> + .remove = vfio_ccw_mdev_remove,
> +};
> +
> static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
> .owner = THIS_MODULE,
> + .device_driver = &vfio_ccw_mdev_driver,
> .supported_type_groups = mdev_type_groups,
> - .create = vfio_ccw_mdev_create,
> - .remove = vfio_ccw_mdev_remove,
> - .open_device = vfio_ccw_mdev_open_device,
> - .close_device = vfio_ccw_mdev_close_device,
> - .read = vfio_ccw_mdev_read,
> - .write = vfio_ccw_mdev_write,
> - .ioctl = vfio_ccw_mdev_ioctl,
> - .request = vfio_ccw_mdev_request,
> };
>
> 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 b2c762eb42b9bb..7272eb78861244 100644
> --- a/drivers/s390/cio/vfio_ccw_private.h
> +++ b/drivers/s390/cio/vfio_ccw_private.h
> @@ -17,6 +17,7 @@
> #include <linux/eventfd.h>
> #include <linux/workqueue.h>
> #include <linux/vfio_ccw.h>
> +#include <linux/vfio.h>
> #include <asm/crw.h>
> #include <asm/debug.h>
>
> @@ -67,6 +68,7 @@ struct vfio_ccw_crw {
>
> /**
> * struct vfio_ccw_private
> + * @vdev: Embedded VFIO device
> * @sch: pointer to the subchannel
> * @state: internal state of the device
> * @completion: synchronization helper of the I/O completion
> @@ -90,6 +92,7 @@ struct vfio_ccw_crw {
> * @crw_work: work for deferral process of CRW handling
> */
> struct vfio_ccw_private {
> + struct vfio_device vdev;
> struct subchannel *sch;
> int state;
> struct completion *completion;
> @@ -121,6 +124,8 @@ extern void vfio_ccw_mdev_unreg(struct subchannel
> *sch);
>
> extern int vfio_ccw_sch_quiesce(struct subchannel *sch);
>
> +extern struct mdev_driver vfio_ccw_mdev_driver;
> +
> /*
> * States of the device statemachine.
> */
