[PATCH v2 07/13] vfio/ccw: Convert to use vfio_register_group_dev()

Jason Gunthorpe
2021-04-26T20:00:35Z

This is more complicated because vfio_ccw is sharing the vfio_device
between both the mdev_device and its vfio_device and the css_driver.

The mdev is a singleton, and the reason for this sharing appears to be to
allow the extra css_driver function callbacks to be delivered to the
vfio_device.

This keeps things as they were, with the css_driver allocating the
singleton, not the mdev_driver, this is pretty confusing. I'm also
uncertain how the lifetime model for the mdev works in the css_driver
callbacks.

At this point 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>
---
drivers/s390/cio/vfio_ccw_drv.c | 21 +++--
drivers/s390/cio/vfio_ccw_ops.c | 135 +++++++++++++++-------------
drivers/s390/cio/vfio_ccw_private.h | 5 ++
3 files changed, 94 insertions(+), 67 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 8c625b530035f5..55c4876dfd139d 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -442,7 +442,7 @@ 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",
@@ -451,7 +451,7 @@ 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",
@@ -460,7 +460,7 @@ 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",
@@ -470,7 +470,7 @@ 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",
@@ -480,19 +480,25 @@ 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();
@@ -501,6 +507,7 @@ static int __init vfio_ccw_sch_init(void)

static void __exit vfio_ccw_sch_exit(void)
{
+ mdev_unregister_driver(&vfio_ccw_mdev_driver);
css_driver_unregister(&vfio_ccw_sch_driver);
isc_unregister(VFIO_CCW_ISC);
vfio_ccw_destroy_regions();
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 491a64c61fff1a..0fcf46031d3821 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -17,13 +17,13 @@

#include "vfio_ccw_private.h"

-static int vfio_ccw_mdev_reset(struct mdev_device *mdev)
+static const struct vfio_device_ops vfio_ccw_dev_ops;
+
+static int vfio_ccw_mdev_reset(struct vfio_ccw_private *private)
{
- struct vfio_ccw_private *private;
struct subchannel *sch;
int ret;

- private = dev_get_drvdata(mdev_parent_dev(mdev));
sch = private->sch;
/*
* TODO:
@@ -61,7 +61,7 @@ static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
if (!cp_iova_pinned(&private->cp, unmap->iova))
return NOTIFY_OK;

- if (vfio_ccw_mdev_reset(private->mdev))
+ if (vfio_ccw_mdev_reset(private))
return NOTIFY_BAD;

cp_free(&private->cp);
@@ -113,10 +113,11 @@ 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));
+ int ret;

if (private->state == VFIO_CCW_STATE_NOT_OPER)
return -ENODEV;
@@ -124,6 +125,10 @@ 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;

@@ -132,19 +137,28 @@ static int vfio_ccw_mdev_create(struct mdev_device *mdev)
private->sch->schid.ssid,
private->sch->schid.sch_no);

+ ret = vfio_register_group_dev(&private->vdev);
+ if (ret)
+ goto err_atomic;
+ dev_set_drvdata(&mdev->dev, private);
return 0;
+
+err_atomic:
+ atomic_inc(&private->avail);
+ 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);

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))
@@ -155,20 +169,18 @@ static int vfio_ccw_mdev_remove(struct mdev_device *mdev)
cp_free(&private->cp);
private->mdev = NULL;
atomic_inc(&private->avail);
-
- return 0;
}

-static int vfio_ccw_mdev_open(struct mdev_device *mdev)
+static int vfio_ccw_mdev_open(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;
@@ -189,27 +201,26 @@ static int vfio_ccw_mdev_open(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_release(struct mdev_device *mdev)
+static void vfio_ccw_mdev_release(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)) {
- if (!vfio_ccw_mdev_reset(mdev))
+ if (!vfio_ccw_mdev_reset(private))
private->state = VFIO_CCW_STATE_STANDBY;
/* The state will be NOT_OPER on error. */
}

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,
@@ -233,15 +244,14 @@ 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;
@@ -288,15 +298,14 @@ 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;
@@ -313,12 +322,9 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
return -EINVAL;
}

-static int vfio_ccw_mdev_get_device_info(struct vfio_device_info *info,
- struct mdev_device *mdev)
+static int vfio_ccw_mdev_get_device_info(struct vfio_ccw_private *private,
+ struct vfio_device_info *info)
{
- struct vfio_ccw_private *private;
-
- private = dev_get_drvdata(mdev_parent_dev(mdev));
info->flags = VFIO_DEVICE_FLAGS_CCW | VFIO_DEVICE_FLAGS_RESET;
info->num_regions = VFIO_CCW_NUM_REGIONS + private->num_regions;
info->num_irqs = VFIO_CCW_NUM_IRQS;
@@ -326,14 +332,12 @@ static int vfio_ccw_mdev_get_device_info(struct vfio_device_info *info,
return 0;
}

-static int vfio_ccw_mdev_get_region_info(struct vfio_region_info *info,
- struct mdev_device *mdev,
+static int vfio_ccw_mdev_get_region_info(struct vfio_ccw_private *private,
+ struct vfio_region_info *info,
unsigned long arg)
{
- struct vfio_ccw_private *private;
int i;

- private = dev_get_drvdata(mdev_parent_dev(mdev));
switch (info->index) {
case VFIO_CCW_CONFIG_REGION_INDEX:
info->offset = 0;
@@ -408,19 +412,16 @@ static int vfio_ccw_mdev_get_irq_info(struct vfio_irq_info *info)
return 0;
}

-static int vfio_ccw_mdev_set_irqs(struct mdev_device *mdev,
+static int vfio_ccw_mdev_set_irqs(struct vfio_ccw_private *private,
uint32_t flags,
uint32_t index,
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));
-
switch (index) {
case VFIO_CCW_IO_IRQ_INDEX:
ctx = &private->io_trigger;
@@ -522,10 +523,12 @@ 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 =
+ container_of(vdev, struct vfio_ccw_private, vdev);
int ret = 0;
unsigned long minsz;

@@ -542,7 +545,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
if (info.argsz < minsz)
return -EINVAL;

- ret = vfio_ccw_mdev_get_device_info(&info, mdev);
+ ret = vfio_ccw_mdev_get_device_info(private, &info);
if (ret)
return ret;

@@ -560,7 +563,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
if (info.argsz < minsz)
return -EINVAL;

- ret = vfio_ccw_mdev_get_region_info(&info, mdev, arg);
+ ret = vfio_ccw_mdev_get_region_info(private, &info, arg);
if (ret)
return ret;

@@ -605,47 +608,59 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
return ret;

data = (void __user *)(arg + minsz);
- return vfio_ccw_mdev_set_irqs(mdev, hdr.flags, hdr.index, data);
+ return vfio_ccw_mdev_set_irqs(private, hdr.flags, hdr.index,
+ data);
}
case VFIO_DEVICE_RESET:
- return vfio_ccw_mdev_reset(mdev);
+ return vfio_ccw_mdev_reset(private);
default:
return -ENOTTY;
}
}

/* 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 = private->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 = vfio_ccw_mdev_open,
+ .release = vfio_ccw_mdev_release,
+ .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 = vfio_ccw_mdev_open,
- .release = vfio_ccw_mdev_release,
- .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.
*/
--
2.31.1