Re: [PATCH v3 04/10] vfio/ccw: Convert to use vfio_register_emulated_iommu_dev()

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 jgg@nvidia.com

Reviewed-by: Eric Farman farman@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.

*/