// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2021-2022, NVIDIA CORPORATION & AFFILIATES
 */
#include <linux/vfio.h>
#include <linux/iommufd.h>

#include "vfio.h"

MODULE_IMPORT_NS("IOMMUFD");
MODULE_IMPORT_NS("IOMMUFD_VFIO");

bool vfio_iommufd_device_has_compat_ioas(struct vfio_device *vdev,
                                         struct iommufd_ctx *ictx)
{
        u32 ioas_id;

        return !iommufd_vfio_compat_ioas_get_id(ictx, &ioas_id);
}

int vfio_df_iommufd_bind(struct vfio_device_file *df)
{
        struct vfio_device *vdev = df->device;
        struct iommufd_ctx *ictx = df->iommufd;

        lockdep_assert_held(&vdev->dev_set->lock);

        /* Returns 0 to permit device opening under noiommu mode */
        if (vfio_device_is_noiommu(vdev))
                return 0;

        return vdev->ops->bind_iommufd(vdev, ictx, &df->devid);
}

int vfio_iommufd_compat_attach_ioas(struct vfio_device *vdev,
                                    struct iommufd_ctx *ictx)
{
        u32 ioas_id;
        int ret;

        lockdep_assert_held(&vdev->dev_set->lock);

        /* compat noiommu does not need to do ioas attach */
        if (vfio_device_is_noiommu(vdev))
                return 0;

        ret = iommufd_vfio_compat_ioas_get_id(ictx, &ioas_id);
        if (ret)
                return ret;

        /* The legacy path has no way to return the selected pt_id */
        return vdev->ops->attach_ioas(vdev, &ioas_id);
}

void vfio_df_iommufd_unbind(struct vfio_device_file *df)
{
        struct vfio_device *vdev = df->device;

        lockdep_assert_held(&vdev->dev_set->lock);

        if (vfio_device_is_noiommu(vdev))
                return;

        if (vdev->ops->unbind_iommufd)
                vdev->ops->unbind_iommufd(vdev);
}

struct iommufd_ctx *vfio_iommufd_device_ictx(struct vfio_device *vdev)
{
        if (vdev->iommufd_device)
                return iommufd_device_to_ictx(vdev->iommufd_device);
        return NULL;
}
EXPORT_SYMBOL_GPL(vfio_iommufd_device_ictx);

static int vfio_iommufd_device_id(struct vfio_device *vdev)
{
        if (vdev->iommufd_device)
                return iommufd_device_to_id(vdev->iommufd_device);
        return -EINVAL;
}

/*
 * Return devid for a device.
 *  valid ID for the device that is owned by the ictx
 *  -ENOENT = device is owned but there is no ID
 *  -ENODEV or other error = device is not owned
 */
int vfio_iommufd_get_dev_id(struct vfio_device *vdev, struct iommufd_ctx *ictx)
{
        struct iommu_group *group;
        int devid;

        if (vfio_iommufd_device_ictx(vdev) == ictx)
                return vfio_iommufd_device_id(vdev);

        group = iommu_group_get(vdev->dev);
        if (!group)
                return -ENODEV;

        if (iommufd_ctx_has_group(ictx, group))
                devid = -ENOENT;
        else
                devid = -ENODEV;

        iommu_group_put(group);

        return devid;
}
EXPORT_SYMBOL_GPL(vfio_iommufd_get_dev_id);

/*
 * The physical standard ops mean that the iommufd_device is bound to the
 * physical device vdev->dev that was provided to vfio_init_group_dev(). Drivers
 * using this ops set should call vfio_register_group_dev()
 */
int vfio_iommufd_physical_bind(struct vfio_device *vdev,
                               struct iommufd_ctx *ictx, u32 *out_device_id)
{
        struct iommufd_device *idev;

        idev = iommufd_device_bind(ictx, vdev->dev, out_device_id);
        if (IS_ERR(idev))
                return PTR_ERR(idev);
        vdev->iommufd_device = idev;
        ida_init(&vdev->pasids);
        return 0;
}
EXPORT_SYMBOL_GPL(vfio_iommufd_physical_bind);

void vfio_iommufd_physical_unbind(struct vfio_device *vdev)
{
        int pasid;

        lockdep_assert_held(&vdev->dev_set->lock);

        while ((pasid = ida_find_first(&vdev->pasids)) >= 0) {
                iommufd_device_detach(vdev->iommufd_device, pasid);
                ida_free(&vdev->pasids, pasid);
        }

        if (vdev->iommufd_attached) {
                iommufd_device_detach(vdev->iommufd_device, IOMMU_NO_PASID);
                vdev->iommufd_attached = false;
        }
        iommufd_device_unbind(vdev->iommufd_device);
        vdev->iommufd_device = NULL;
}
EXPORT_SYMBOL_GPL(vfio_iommufd_physical_unbind);

int vfio_iommufd_physical_attach_ioas(struct vfio_device *vdev, u32 *pt_id)
{
        int rc;

        lockdep_assert_held(&vdev->dev_set->lock);

        if (WARN_ON(!vdev->iommufd_device))
                return -EINVAL;

        if (vdev->iommufd_attached)
                rc = iommufd_device_replace(vdev->iommufd_device,
                                            IOMMU_NO_PASID, pt_id);
        else
                rc = iommufd_device_attach(vdev->iommufd_device,
                                           IOMMU_NO_PASID, pt_id);
        if (rc)
                return rc;
        vdev->iommufd_attached = true;
        return 0;
}
EXPORT_SYMBOL_GPL(vfio_iommufd_physical_attach_ioas);

void vfio_iommufd_physical_detach_ioas(struct vfio_device *vdev)
{
        lockdep_assert_held(&vdev->dev_set->lock);

        if (WARN_ON(!vdev->iommufd_device) || !vdev->iommufd_attached)
                return;

        iommufd_device_detach(vdev->iommufd_device, IOMMU_NO_PASID);
        vdev->iommufd_attached = false;
}
EXPORT_SYMBOL_GPL(vfio_iommufd_physical_detach_ioas);

int vfio_iommufd_physical_pasid_attach_ioas(struct vfio_device *vdev,
                                            u32 pasid, u32 *pt_id)
{
        int rc;

        lockdep_assert_held(&vdev->dev_set->lock);

        if (WARN_ON(!vdev->iommufd_device))
                return -EINVAL;

        if (ida_exists(&vdev->pasids, pasid))
                return iommufd_device_replace(vdev->iommufd_device,
                                              pasid, pt_id);

        rc = ida_alloc_range(&vdev->pasids, pasid, pasid, GFP_KERNEL);
        if (rc < 0)
                return rc;

        rc = iommufd_device_attach(vdev->iommufd_device, pasid, pt_id);
        if (rc)
                ida_free(&vdev->pasids, pasid);

        return rc;
}
EXPORT_SYMBOL_GPL(vfio_iommufd_physical_pasid_attach_ioas);

void vfio_iommufd_physical_pasid_detach_ioas(struct vfio_device *vdev,
                                             u32 pasid)
{
        lockdep_assert_held(&vdev->dev_set->lock);

        if (WARN_ON(!vdev->iommufd_device))
                return;

        if (!ida_exists(&vdev->pasids, pasid))
                return;

        iommufd_device_detach(vdev->iommufd_device, pasid);
        ida_free(&vdev->pasids, pasid);
}
EXPORT_SYMBOL_GPL(vfio_iommufd_physical_pasid_detach_ioas);

/*
 * The emulated standard ops mean that vfio_device is going to use the
 * "mdev path" and will call vfio_pin_pages()/vfio_dma_rw(). Drivers using this
 * ops set should call vfio_register_emulated_iommu_dev(). Drivers that do
 * not call vfio_pin_pages()/vfio_dma_rw() have no need to provide dma_unmap.
 */

static void vfio_emulated_unmap(void *data, unsigned long iova,
                                unsigned long length)
{
        struct vfio_device *vdev = data;

        if (vdev->ops->dma_unmap)
                vdev->ops->dma_unmap(vdev, iova, length);
}

static const struct iommufd_access_ops vfio_user_ops = {
        .needs_pin_pages = 1,
        .unmap = vfio_emulated_unmap,
};

int vfio_iommufd_emulated_bind(struct vfio_device *vdev,
                               struct iommufd_ctx *ictx, u32 *out_device_id)
{
        struct iommufd_access *user;

        lockdep_assert_held(&vdev->dev_set->lock);

        user = iommufd_access_create(ictx, &vfio_user_ops, vdev, out_device_id);
        if (IS_ERR(user))
                return PTR_ERR(user);
        vdev->iommufd_access = user;
        return 0;
}
EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_bind);

void vfio_iommufd_emulated_unbind(struct vfio_device *vdev)
{
        lockdep_assert_held(&vdev->dev_set->lock);

        if (vdev->iommufd_access) {
                iommufd_access_destroy(vdev->iommufd_access);
                vdev->iommufd_attached = false;
                vdev->iommufd_access = NULL;
        }
}
EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_unbind);

int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id)
{
        int rc;

        lockdep_assert_held(&vdev->dev_set->lock);

        if (vdev->iommufd_attached)
                rc = iommufd_access_replace(vdev->iommufd_access, *pt_id);
        else
                rc = iommufd_access_attach(vdev->iommufd_access, *pt_id);
        if (rc)
                return rc;
        vdev->iommufd_attached = true;
        return 0;
}
EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_attach_ioas);

void vfio_iommufd_emulated_detach_ioas(struct vfio_device *vdev)
{
        lockdep_assert_held(&vdev->dev_set->lock);

        if (WARN_ON(!vdev->iommufd_access) ||
            !vdev->iommufd_attached)
                return;

        iommufd_access_detach(vdev->iommufd_access);
        vdev->iommufd_attached = false;
}
EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_detach_ioas);