Re: [PATCH v2 06/13] vfio/ap_ops: Convert to use vfio_register_group_dev()

Tony Krowiak
2021-05-04T14:42:18Z

On 4/26/21 4:00 PM, Jason Gunthorpe wrote:
> This is straightforward conversion, the ap_matrix_mdev is actually serving
> as the vfio_device and we can replace all the mdev_get_drvdata()'s with a
> simple container_of().

This is a nit, but most of the mdev_get_drvdata()'s are not being
replaced by container_of(); in most places, the replacement is
dev_get_drvdata().

>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
> drivers/s390/crypto/vfio_ap_ops.c | 137 ++++++++++++++++----------
> drivers/s390/crypto/vfio_ap_private.h | 2 +
> 2 files changed, 89 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 0ce00c9311d378..79872c857dd522 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -24,8 +24,9 @@
> #define VFIO_AP_MDEV_TYPE_HWVIRT "passthrough"
> #define VFIO_AP_MDEV_NAME_HWVIRT "VFIO AP Passthrough Device"
>
> -static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);
> +static int vfio_ap_mdev_reset_queues(struct ap_matrix_mdev *matrix_mdev);
> static struct vfio_ap_queue *vfio_ap_find_queue(int apqn);
> +static const struct vfio_device_ops vfio_ap_matrix_dev_ops;
>
> static int match_apqn(struct device *dev, const void *data)
> {
> @@ -322,48 +323,63 @@ static void vfio_ap_matrix_init(struct ap_config_info *info,
> matrix->adm_max = info->apxa ? info->Nd : 15;
> }
>
> -static int vfio_ap_mdev_create(struct mdev_device *mdev)
> +static int vfio_ap_mdev_probe(struct mdev_device *mdev)
> {
> struct ap_matrix_mdev *matrix_mdev;
> + int ret;
>
> if ((atomic_dec_if_positive(&matrix_dev->available_instances) < 0))
> return -EPERM;
>
> matrix_mdev = kzalloc(sizeof(*matrix_mdev), GFP_KERNEL);
> if (!matrix_mdev) {
> - atomic_inc(&matrix_dev->available_instances);
> - return -ENOMEM;
> + ret = -ENOMEM;
> + goto err_atomic;
> }
> + vfio_init_group_dev(&matrix_mdev->vdev, &mdev->dev,
> + &vfio_ap_matrix_dev_ops);
>
> matrix_mdev->mdev = mdev;
> vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix);
> - mdev_set_drvdata(mdev, matrix_mdev);
> matrix_mdev->pqap_hook.hook = handle_pqap;
> matrix_mdev->pqap_hook.owner = THIS_MODULE;
> mutex_lock(&matrix_dev->lock);
> list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
> mutex_unlock(&matrix_dev->lock);
>
> + ret = vfio_register_group_dev(&matrix_mdev->vdev);
> + if (ret)
> + goto err_list;
> + dev_set_drvdata(&mdev->dev, matrix_mdev);

I'm wondering whether the code above should be done under
the matrix_dev->lock. Does the mdev exist in the sysfs at the
point the probe is called? If so, then is it possible for functions
that acquire the matrix_mdev from the drvdata to get called before
the drvdata is set?

> return 0;
> +
> +err_list:
> + mutex_lock(&matrix_dev->lock);
> + list_del(&matrix_mdev->node);
> + mutex_unlock(&matrix_dev->lock);
> + kfree(matrix_mdev);
> +err_atomic:
> + atomic_inc(&matrix_dev->available_instances);
> + return ret;
> }
>
> -static int vfio_ap_mdev_remove(struct mdev_device *mdev)
> +static void vfio_ap_mdev_remove(struct mdev_device *mdev)
> {
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(&mdev->dev);
>
> - if (matrix_mdev->kvm)
> - return -EBUSY;
> + /* FIXME: Remove isn't allowed to fail */
> + if (WARN_ON(matrix_mdev->kvm))
> + return;
> +
> + vfio_unregister_group_dev(&matrix_mdev->vdev);
>
> mutex_lock(&matrix_dev->lock);
> - vfio_ap_mdev_reset_queues(mdev);
> + vfio_ap_mdev_reset_queues(matrix_mdev);
> list_del(&matrix_mdev->node);
> mutex_unlock(&matrix_dev->lock);
>
> kfree(matrix_mdev);
> - mdev_set_drvdata(mdev, NULL);
> atomic_inc(&matrix_dev->available_instances);
> -
> - return 0;
> }
>
> static ssize_t name_show(struct mdev_type *mtype,
> @@ -605,8 +621,7 @@ static ssize_t assign_adapter_store(struct device *dev,
> {
> int ret;
> unsigned long apid;
> - struct mdev_device *mdev = mdev_from_dev(dev);
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
>
> /* If the guest is running, disallow assignment of adapter */
> if (matrix_mdev->kvm)
> @@ -671,8 +686,7 @@ static ssize_t unassign_adapter_store(struct device *dev,
> {
> int ret;
> unsigned long apid;
> - struct mdev_device *mdev = mdev_from_dev(dev);
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
>
> /* If the guest is running, disallow un-assignment of adapter */
> if (matrix_mdev->kvm)
> @@ -751,8 +765,7 @@ static ssize_t assign_domain_store(struct device *dev,
> {
> int ret;
> unsigned long apqi;
> - struct mdev_device *mdev = mdev_from_dev(dev);
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
> unsigned long max_apqi = matrix_mdev->matrix.aqm_max;
>
> /* If the guest is running, disallow assignment of domain */
> @@ -813,8 +826,7 @@ static ssize_t unassign_domain_store(struct device *dev,
> {
> int ret;
> unsigned long apqi;
> - struct mdev_device *mdev = mdev_from_dev(dev);
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
>
> /* If the guest is running, disallow un-assignment of domain */
> if (matrix_mdev->kvm)
> @@ -857,8 +869,7 @@ static ssize_t assign_control_domain_store(struct device *dev,
> {
> int ret;
> unsigned long id;
> - struct mdev_device *mdev = mdev_from_dev(dev);
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
>
> /* If the guest is running, disallow assignment of control domain */
> if (matrix_mdev->kvm)
> @@ -906,8 +917,7 @@ static ssize_t unassign_control_domain_store(struct device *dev,
> {
> int ret;
> unsigned long domid;
> - struct mdev_device *mdev = mdev_from_dev(dev);
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
> unsigned long max_domid = matrix_mdev->matrix.adm_max;
>
> /* If the guest is running, disallow un-assignment of control domain */
> @@ -936,8 +946,7 @@ static ssize_t control_domains_show(struct device *dev,
> int nchars = 0;
> int n;
> char *bufpos = buf;
> - struct mdev_device *mdev = mdev_from_dev(dev);
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
> unsigned long max_domid = matrix_mdev->matrix.adm_max;
>
> mutex_lock(&matrix_dev->lock);
> @@ -955,8 +964,7 @@ static DEVICE_ATTR_RO(control_domains);
> static ssize_t matrix_show(struct device *dev, struct device_attribute *attr,
> char *buf)
> {
> - struct mdev_device *mdev = mdev_from_dev(dev);
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
> char *bufpos = buf;
> unsigned long apid;
> unsigned long apqi;
> @@ -1085,7 +1093,7 @@ static void vfio_ap_mdev_unset_kvm(struct ap_matrix_mdev *matrix_mdev)
> {
> kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
> matrix_mdev->kvm->arch.crypto.pqap_hook = NULL;
> - vfio_ap_mdev_reset_queues(matrix_mdev->mdev);
> + vfio_ap_mdev_reset_queues(matrix_mdev);
> kvm_put_kvm(matrix_mdev->kvm);
> matrix_mdev->kvm = NULL;
> }
> @@ -1195,13 +1203,12 @@ int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,
> return ret;
> }
>
> -static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
> +static int vfio_ap_mdev_reset_queues(struct ap_matrix_mdev *matrix_mdev)
> {
> int ret;
> int rc = 0;
> unsigned long apid, apqi;
> struct vfio_ap_queue *q;
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
>
> for_each_set_bit_inv(apid, matrix_mdev->matrix.apm,
> matrix_mdev->matrix.apm_max + 1) {
> @@ -1222,9 +1229,10 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
> return rc;
> }
>
> -static int vfio_ap_mdev_open(struct mdev_device *mdev)
> +static int vfio_ap_mdev_open(struct vfio_device *vdev)
> {
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct ap_matrix_mdev *matrix_mdev =
> + container_of(vdev, struct ap_matrix_mdev, vdev);
> unsigned long events;
> int ret;
>
> @@ -1235,7 +1243,7 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev)
> matrix_mdev->group_notifier.notifier_call = vfio_ap_mdev_group_notifier;
> events = VFIO_GROUP_NOTIFY_SET_KVM;
>
> - ret = vfio_register_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
> + ret = vfio_register_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
> &events, &matrix_mdev->group_notifier);
> if (ret) {
> module_put(THIS_MODULE);
> @@ -1244,29 +1252,30 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev)
>
> matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier;
> events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
> - ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
> + ret = vfio_register_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
> &events, &matrix_mdev->iommu_notifier);
> if (!ret)
> return ret;
>
> - vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
> + vfio_unregister_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
> &matrix_mdev->group_notifier);
> module_put(THIS_MODULE);
> return ret;
> }
>
> -static void vfio_ap_mdev_release(struct mdev_device *mdev)
> +static void vfio_ap_mdev_release(struct vfio_device *vdev)
> {
> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + struct ap_matrix_mdev *matrix_mdev =
> + container_of(vdev, struct ap_matrix_mdev, vdev);
>
> mutex_lock(&matrix_dev->lock);
> if (matrix_mdev->kvm)
> vfio_ap_mdev_unset_kvm(matrix_mdev);
> mutex_unlock(&matrix_dev->lock);
>
> - vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
> + vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
> &matrix_mdev->iommu_notifier);
> - vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
> + vfio_unregister_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
> &matrix_mdev->group_notifier);
> module_put(THIS_MODULE);
> }
> @@ -1291,9 +1300,11 @@ static int vfio_ap_mdev_get_device_info(unsigned long arg)
> return copy_to_user((void __user *)arg, &info, minsz) ? -EFAULT : 0;
> }
>
> -static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev,
> +static ssize_t vfio_ap_mdev_ioctl(struct vfio_device *vdev,
> unsigned int cmd, unsigned long arg)
> {
> + struct ap_matrix_mdev *matrix_mdev =
> + container_of(vdev, struct ap_matrix_mdev, vdev);
> int ret;
>
> mutex_lock(&matrix_dev->lock);
> @@ -1302,7 +1313,7 @@ static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev,
> ret = vfio_ap_mdev_get_device_info(arg);
> break;
> case VFIO_DEVICE_RESET:
> - ret = vfio_ap_mdev_reset_queues(mdev);
> + ret = vfio_ap_mdev_reset_queues(matrix_mdev);
> break;
> default:
> ret = -EOPNOTSUPP;
> @@ -1313,25 +1324,51 @@ static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev,
> return ret;
> }
>
> +static const struct vfio_device_ops vfio_ap_matrix_dev_ops = {
> + .open = vfio_ap_mdev_open,
> + .release = vfio_ap_mdev_release,
> + .ioctl = vfio_ap_mdev_ioctl,
> +};
> +
> +static struct mdev_driver vfio_ap_matrix_driver = {
> + .driver = {
> + .name = "vfio_ap_mdev",
> + .owner = THIS_MODULE,
> + .mod_name = KBUILD_MODNAME,
> + .dev_groups = vfio_ap_mdev_attr_groups,
> + },
> + .probe = vfio_ap_mdev_probe,
> + .remove = vfio_ap_mdev_remove,
> +};
> +
> static const struct mdev_parent_ops vfio_ap_matrix_ops = {
> .owner = THIS_MODULE,
> + .device_driver = &vfio_ap_matrix_driver,
> .supported_type_groups = vfio_ap_mdev_type_groups,
> - .mdev_attr_groups = vfio_ap_mdev_attr_groups,
> - .create = vfio_ap_mdev_create,
> - .remove = vfio_ap_mdev_remove,
> - .open = vfio_ap_mdev_open,
> - .release = vfio_ap_mdev_release,
> - .ioctl = vfio_ap_mdev_ioctl,
> };
>
> int vfio_ap_mdev_register(void)
> {
> + int ret;
> +
> atomic_set(&matrix_dev->available_instances, MAX_ZDEV_ENTRIES_EXT);
>
> - return mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_ops);
> + ret = mdev_register_driver(&vfio_ap_matrix_driver);
> + if (ret)
> + return ret;
> +
> + ret = mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_ops);
> + if (ret)
> + goto err_driver;
> + return 0;
> +
> +err_driver:
> + mdev_unregister_driver(&vfio_ap_matrix_driver);
> + return ret;
> }
>
> void vfio_ap_mdev_unregister(void)
> {
> mdev_unregister_device(&matrix_dev->device);
> + mdev_unregister_driver(&vfio_ap_matrix_driver);
> }
> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
> index 28e9d998976820..b95ba674f60b1b 100644
> --- a/drivers/s390/crypto/vfio_ap_private.h
> +++ b/drivers/s390/crypto/vfio_ap_private.h
> @@ -18,6 +18,7 @@
> #include <linux/delay.h>
> #include <linux/mutex.h>
> #include <linux/kvm_host.h>
> +#include <linux/vfio.h>
>
> #include "ap_bus.h"
>
> @@ -79,6 +80,7 @@ struct ap_matrix {
> * @kvm: the struct holding guest's state
> */
> struct ap_matrix_mdev {
> + struct vfio_device vdev;
> struct list_head node;
> struct ap_matrix matrix;
> struct notifier_block group_notifier;