vfio: Add VFIO_DEVICE_[AT|DE]TACH_IOMMUFD_PT

This adds ioctl for userspace to attach device cdev fd to and detach
from IOAS/hw_pagetable managed by iommufd.

    VFIO_DEVICE_ATTACH_IOMMUFD_PT: attach vfio device to IOAS or hw_pagetable
				   managed by iommufd. Attach can be undo
				   by VFIO_DEVICE_DETACH_IOMMUFD_PT or device
				   fd close.
    VFIO_DEVICE_DETACH_IOMMUFD_PT: detach vfio device from the current attached
				   IOAS or hw_pagetable managed by iommufd.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20230718135551.6592-24-yi.l.liu@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

3 files changed, 77 insertions, 1 deletions

diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c
index f40784dd5561..e75da0a70d1f 100644
--- a/drivers/vfio/device_cdev.c
+++ b/drivers/vfio/device_cdev.c
@@ -152,6 +152,64 @@ void vfio_df_unbind_iommufd(struct vfio_device_file *df)
 	vfio_device_unblock_group(device);
 }
 
+int vfio_df_ioctl_attach_pt(struct vfio_device_file *df,
+			    struct vfio_device_attach_iommufd_pt __user *arg)
+{
+	struct vfio_device *device = df->device;
+	struct vfio_device_attach_iommufd_pt attach;
+	unsigned long minsz;
+	int ret;
+
+	minsz = offsetofend(struct vfio_device_attach_iommufd_pt, pt_id);
+
+	if (copy_from_user(&attach, arg, minsz))
+		return -EFAULT;
+
+	if (attach.argsz < minsz || attach.flags)
+		return -EINVAL;
+
+	mutex_lock(&device->dev_set->lock);
+	ret = device->ops->attach_ioas(device, &attach.pt_id);
+	if (ret)
+		goto out_unlock;
+
+	if (copy_to_user(&arg->pt_id, &attach.pt_id, sizeof(attach.pt_id))) {
+		ret = -EFAULT;
+		goto out_detach;
+	}
+	mutex_unlock(&device->dev_set->lock);
+
+	return 0;
+
+out_detach:
+	device->ops->detach_ioas(device);
+out_unlock:
+	mutex_unlock(&device->dev_set->lock);
+	return ret;
+}
+
+int vfio_df_ioctl_detach_pt(struct vfio_device_file *df,
+			    struct vfio_device_detach_iommufd_pt __user *arg)
+{
+	struct vfio_device *device = df->device;
+	struct vfio_device_detach_iommufd_pt detach;
+	unsigned long minsz;
+
+	minsz = offsetofend(struct vfio_device_detach_iommufd_pt, flags);
+
+	if (copy_from_user(&detach, arg, minsz))
+		return -EFAULT;
+
+	if (detach.argsz < minsz || detach.flags)
+		return -EINVAL;
+
+	mutex_lock(&device->dev_set->lock);
+	device->ops->detach_ioas(device);
+	mutex_unlock(&device->dev_set->lock);
+
+	return 0;
+}
+
 static char *vfio_device_devnode(const struct device *dev, umode_t *mode)
 {
 	return kasprintf(GFP_KERNEL, "vfio/devices/%s", dev_name(dev));
diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
index b6d4ba1ef2b8..8353774a5d07 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -266,6 +266,11 @@ vfio_iommufd_compat_attach_ioas(struct vfio_device *device,
 }
 #endif
 
+int vfio_df_ioctl_attach_pt(struct vfio_device_file *df,
+			    struct vfio_device_attach_iommufd_pt __user *arg);
+int vfio_df_ioctl_detach_pt(struct vfio_device_file *df,
+			    struct vfio_device_detach_iommufd_pt __user *arg);
+
 #if IS_ENABLED(CONFIG_VFIO_DEVICE_CDEV)
 void vfio_init_device_cdev(struct vfio_device *device);
 
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 9fdf93ff17cf..ba1d84afe081 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -1162,6 +1162,19 @@ static long vfio_device_fops_unl_ioctl(struct file *filep,
 	if (ret)
 		return ret;
 
+	/* cdev only ioctls */
+	if (IS_ENABLED(CONFIG_VFIO_DEVICE_CDEV) && !df->group) {
+		switch (cmd) {
+		case VFIO_DEVICE_ATTACH_IOMMUFD_PT:
+			ret = vfio_df_ioctl_attach_pt(df, uptr);
+			goto out;
+
+		case VFIO_DEVICE_DETACH_IOMMUFD_PT:
+			ret = vfio_df_ioctl_detach_pt(df, uptr);
+			goto out;
+		}
+	}
+
 	switch (cmd) {
 	case VFIO_DEVICE_FEATURE:
 		ret = vfio_ioctl_device_feature(device, uptr);
@@ -1174,7 +1187,7 @@ static long vfio_device_fops_unl_ioctl(struct file *filep,
 			ret = device->ops->ioctl(device, cmd, arg);
 		break;
 	}
-
+out:
 	vfio_device_pm_runtime_put(device);
 	return ret;
 }