linux-kernel - Re: [PATCH 2/3] vfio: ap: realize the VFIO_DEVICE_SET

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Message-ID: <ea82efce-8dc4-9633-ce3b-51ec2c26efce@redhat.com>
Date:   Wed, 31 May 2023 15:00:53 +0200
From:   Cédric Le Goater <clegoate@...hat.com>
To:     Tony Krowiak <akrowiak@...ux.ibm.com>, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     jjherne@...ux.ibm.com, pasic@...ux.ibm.com, farman@...ux.ibm.com,
        mjrosato@...ux.ibm.com, alex.williamson@...hat.com,
        borntraeger@...ux.ibm.com
Subject: Re: [PATCH 2/3] vfio: ap: realize the VFIO_DEVICE_SET_IRQS ioctl

On 5/31/23 00:35, Tony Krowiak wrote:
> Realize the VFIO_DEVICE_SET_IRQS ioctl to set an eventfd file descriptor
> to be used by the vfio_ap device driver to signal a device request to
> userspace.
> 
> Signed-off-by: Tony Krowiak <akrowiak@...ux.ibm.com>

Reviewed-by: Cédric Le Goater <clg@...hat.com>

Thanks,

C.


> ---
>   drivers/s390/crypto/vfio_ap_ops.c     | 83 +++++++++++++++++++++++++++
>   drivers/s390/crypto/vfio_ap_private.h |  3 +
>   2 files changed, 86 insertions(+)
> 
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 35cd90eee937..44f159136891 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -716,6 +716,7 @@ static int vfio_ap_mdev_probe(struct mdev_device *mdev)
>   	ret = vfio_register_emulated_iommu_dev(&matrix_mdev->vdev);
>   	if (ret)
>   		goto err_put_vdev;
> +	matrix_mdev->req_trigger = NULL;
>   	dev_set_drvdata(&mdev->dev, matrix_mdev);
>   	mutex_lock(&matrix_dev->mdevs_lock);
>   	list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
> @@ -1780,6 +1781,85 @@ static ssize_t vfio_ap_get_irq_info(unsigned long arg)
>   	return copy_to_user((void __user *)arg, &info, minsz) ? -EFAULT : 0;
>   }
>   
> +static int vfio_ap_irq_set_init(struct vfio_irq_set *irq_set, unsigned long arg)
> +{
> +	int ret;
> +	size_t data_size;
> +	unsigned long minsz;
> +
> +	minsz = offsetofend(struct vfio_irq_set, count);
> +
> +	if (copy_from_user(irq_set, (void __user *)arg, minsz))
> +		return -EFAULT;
> +
> +	ret = vfio_set_irqs_validate_and_prepare(irq_set, 1, VFIO_AP_NUM_IRQS,
> +						 &data_size);
> +	if (ret)
> +		return ret;
> +
> +	if (!(irq_set->flags & VFIO_IRQ_SET_ACTION_TRIGGER))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int vfio_ap_set_request_irq(struct ap_matrix_mdev *matrix_mdev,
> +				   unsigned long arg)
> +{
> +	s32 fd;
> +	void __user *data;
> +	unsigned long minsz;
> +	struct eventfd_ctx *req_trigger;
> +
> +	minsz = offsetofend(struct vfio_irq_set, count);
> +	data = (void __user *)(arg + minsz);
> +
> +	if (get_user(fd, (s32 __user *)data))
> +		return -EFAULT;
> +
> +	if (fd == -1) {
> +		if (matrix_mdev->req_trigger)
> +			eventfd_ctx_put(matrix_mdev->req_trigger);
> +		matrix_mdev->req_trigger = NULL;
> +	} else if (fd >= 0) {
> +		req_trigger = eventfd_ctx_fdget(fd);
> +		if (IS_ERR(req_trigger))
> +			return PTR_ERR(req_trigger);
> +
> +		if (matrix_mdev->req_trigger)
> +			eventfd_ctx_put(matrix_mdev->req_trigger);
> +
> +		matrix_mdev->req_trigger = req_trigger;
> +	} else {
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int vfio_ap_set_irqs(struct ap_matrix_mdev *matrix_mdev,
> +			    unsigned long arg)
> +{
> +	int ret;
> +	struct vfio_irq_set irq_set;
> +
> +	ret = vfio_ap_irq_set_init(&irq_set, arg);
> +	if (ret)
> +		return ret;
> +
> +	switch (irq_set.flags & VFIO_IRQ_SET_DATA_TYPE_MASK) {
> +	case VFIO_IRQ_SET_DATA_EVENTFD:
> +		switch (irq_set.index) {
> +		case VFIO_AP_REQ_IRQ_INDEX:
> +			return vfio_ap_set_request_irq(matrix_mdev, arg);
> +		default:
> +			return -EINVAL;
> +		}
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
>   static ssize_t vfio_ap_mdev_ioctl(struct vfio_device *vdev,
>   				    unsigned int cmd, unsigned long arg)
>   {
> @@ -1798,6 +1878,9 @@ static ssize_t vfio_ap_mdev_ioctl(struct vfio_device *vdev,
>   	case VFIO_DEVICE_GET_IRQ_INFO:
>   			ret = vfio_ap_get_irq_info(arg);
>   			break;
> +	case VFIO_DEVICE_SET_IRQS:
> +		ret = vfio_ap_set_irqs(matrix_mdev, arg);
> +		break;
>   	default:
>   		ret = -EOPNOTSUPP;
>   		break;
> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
> index 976a65f32e7d..4642bbdbd1b2 100644
> --- a/drivers/s390/crypto/vfio_ap_private.h
> +++ b/drivers/s390/crypto/vfio_ap_private.h
> @@ -15,6 +15,7 @@
>   #include <linux/types.h>
>   #include <linux/mdev.h>
>   #include <linux/delay.h>
> +#include <linux/eventfd.h>
>   #include <linux/mutex.h>
>   #include <linux/kvm_host.h>
>   #include <linux/vfio.h>
> @@ -103,6 +104,7 @@ struct ap_queue_table {
>    *		PQAP(AQIC) instruction.
>    * @mdev:	the mediated device
>    * @qtable:	table of queues (struct vfio_ap_queue) assigned to the mdev
> + * @req_trigger eventfd ctx for signaling userspace to return a device
>    * @apm_add:	bitmap of APIDs added to the host's AP configuration
>    * @aqm_add:	bitmap of APQIs added to the host's AP configuration
>    * @adm_add:	bitmap of control domain numbers added to the host's AP
> @@ -117,6 +119,7 @@ struct ap_matrix_mdev {
>   	crypto_hook pqap_hook;
>   	struct mdev_device *mdev;
>   	struct ap_queue_table qtable;
> +	struct eventfd_ctx *req_trigger;
>   	DECLARE_BITMAP(apm_add, AP_DEVICES);
>   	DECLARE_BITMAP(aqm_add, AP_DOMAINS);
>   	DECLARE_BITMAP(adm_add, AP_DOMAINS);