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vfio/ccw: Convert to use vfio_register_emulated_iommu_dev()
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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.

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.

Reviewed-by: Eric Farman <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alex Williamson <[email protected]>
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@jgunthorpe @awilliam
jgunthorpe authored and awilliam committed Oct 28, 2021
1 parent 39b6ee0 commit 3bf1311
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Showing 3 changed files with 85 additions and 48 deletions.
21 changes: 14 additions & 7 deletions drivers/s390/cio/vfio_ccw_drv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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",
Expand All @@ -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",
Expand All @@ -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",
Expand All @@ -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",
Expand All @@ -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();
Expand All @@ -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);
Expand Down
107 changes: 66 additions & 41 deletions drivers/s390/cio/vfio_ccw_ops.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -111,17 +113,21 @@ 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;

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;

Expand All @@ -130,43 +136,54 @@ 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))
private->state = VFIO_CCW_STATE_STANDBY;
/* 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;
Expand All @@ -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)) {
Expand All @@ -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,
Expand All @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -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)
Expand Down
5 changes: 5 additions & 0 deletions drivers/s390/cio/vfio_ccw_private.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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>

Expand Down Expand Up @@ -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
Expand All @@ -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;
Expand Down Expand Up @@ -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.
*/
Expand Down

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