> From: Alex Williamson <[email protected]> > Sent: Thursday, March 30, 2023 5:19 AM > > > Nit, ATDETACH? [AT|DE]TACH?
[AT|DE]TACH 😊 > On Mon, 27 Mar 2023 02:40:45 -0700 > Yi Liu <[email protected]> wrote: > > > 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, 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: Kevin Tian <[email protected]> > > Tested-by: Terrence Xu <[email protected]> > > Tested-by: Nicolin Chen <[email protected]> > > Tested-by: Matthew Rosato <[email protected]> > > Signed-off-by: Yi Liu <[email protected]> > > --- > > drivers/vfio/device_cdev.c | 85 ++++++++++++++++++++++++++++++++++++++ > > drivers/vfio/vfio.h | 16 +++++++ > > drivers/vfio/vfio_main.c | 8 ++++ > > include/uapi/linux/vfio.h | 52 +++++++++++++++++++++++ > > 4 files changed, 161 insertions(+) > > > > diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c > > index 2b563bac50b9..b5de997bff6d 100644 > > --- a/drivers/vfio/device_cdev.c > > +++ b/drivers/vfio/device_cdev.c > > @@ -197,6 +197,91 @@ long vfio_device_ioctl_bind_iommufd(struct > vfio_device_file *df, > > return ret; > > } > > > > +int vfio_ioctl_device_attach(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; > > + > > + static_assert(__same_type(arg->pt_id, attach.pt_id)); > > Same comment as previous, given these are the same field of the same > structure, I don't understand how this could ever assert. yes, will remove it. > > > + > > + 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; > > + > > + if (!device->ops->bind_iommufd) > > + return -ENODEV; > > Same as previous, we already require this to enable cdev support, so > this seems ultra paranoid. will remove it. > > > + > > + /* ATTACH only allowed for cdev fds */ > > + if (df->group) > > + return -EINVAL; > > + > > + mutex_lock(&device->dev_set->lock); > > + /* noiommufd mode doesn't allow attach */ > > + if (!df->iommufd) { > > + ret = -EOPNOTSUPP; > > + goto out_unlock; > > + } > > + > > + ret = device->ops->attach_ioas(device, &attach.pt_id); > > + if (ret) > > + goto out_unlock; > > + > > + ret = copy_to_user(&arg->pt_id, &attach.pt_id, > > + sizeof(attach.pt_id)) ? -EFAULT : 0; > > + if (ret) > > + 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_ioctl_device_detach(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; > > + > > + if (!device->ops->bind_iommufd) > > + return -ENODEV; > > + > > + /* DETACH only allowed for cdev fds */ > > + if (df->group) > > + return -EINVAL; > > + > > + mutex_lock(&device->dev_set->lock); > > + /* noiommufd mode doesn't support detach */ > > + if (!df->iommufd) { > > + mutex_unlock(&device->dev_set->lock); > > + return -EOPNOTSUPP; > > + } > > + device->ops->detach_ioas(device); > > + mutex_unlock(&device->dev_set->lock); > > + > > + return 0; > > +} > > For both of these, can't a user trigger the > WARN_ON(!vdev->iommufd_device) if they call either of these before > VFIO_DEVICE_BIND_IOMMUFD? Thanks, if VFIO_DEVICE_BIND_IOMMUFD is not done, the ATTACH/DETACH shall be blocked, so it won't trigger the WARN_ON which is in the attach_ioas and detach_ioas callback. Regards, Yi Liu > > > + > > 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 ace3d52b0928..c199e410db18 100644 > > --- a/drivers/vfio/vfio.h > > +++ b/drivers/vfio/vfio.h > > @@ -284,6 +284,10 @@ int vfio_device_fops_cdev_open(struct inode *inode, > struct file *filep); > > void vfio_device_cdev_close(struct vfio_device_file *df); > > long vfio_device_ioctl_bind_iommufd(struct vfio_device_file *df, > > struct vfio_device_bind_iommufd __user > > *arg); > > +int vfio_ioctl_device_attach(struct vfio_device_file *df, > > + struct vfio_device_attach_iommufd_pt __user *arg); > > +int vfio_ioctl_device_detach(struct vfio_device_file *df, > > + struct vfio_device_detach_iommufd_pt __user *arg); > > int vfio_cdev_init(struct class *device_class); > > void vfio_cdev_cleanup(void); > > #else > > @@ -317,6 +321,18 @@ static inline long > > vfio_device_ioctl_bind_iommufd(struct > vfio_device_file *df, > > return -EOPNOTSUPP; > > } > > > > +static inline int vfio_ioctl_device_attach(struct vfio_device_file *df, > > + struct vfio_device_attach_iommufd_pt > __user *arg) > > +{ > > + return -EOPNOTSUPP; > > +} > > + > > +static inline int vfio_ioctl_device_detach(struct vfio_device_file *df, > > + struct vfio_device_detach_iommufd_pt > __user *arg) > > +{ > > + return -EOPNOTSUPP; > > +} > > + > > static inline int vfio_cdev_init(struct class *device_class) > > { > > return 0; > > diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c > > index 375086c8803f..896d8bb49585 100644 > > --- a/drivers/vfio/vfio_main.c > > +++ b/drivers/vfio/vfio_main.c > > @@ -1150,6 +1150,14 @@ static long vfio_device_fops_unl_ioctl(struct file > > *filep, > > ret = vfio_ioctl_device_feature(device, (void __user *)arg); > > break; > > > > + case VFIO_DEVICE_ATTACH_IOMMUFD_PT: > > + ret = vfio_ioctl_device_attach(df, (void __user *)arg); > > + break; > > + > > + case VFIO_DEVICE_DETACH_IOMMUFD_PT: > > + ret = vfio_ioctl_device_detach(df, (void __user *)arg); > > + break; > > + > > default: > > if (unlikely(!device->ops->ioctl)) > > ret = -EINVAL; > > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > > index 62b2f2497525..bf6c97e759c7 100644 > > --- a/include/uapi/linux/vfio.h > > +++ b/include/uapi/linux/vfio.h > > @@ -231,6 +231,58 @@ struct vfio_device_bind_iommufd { > > > > #define VFIO_DEVICE_BIND_IOMMUFD _IO(VFIO_TYPE, VFIO_BASE + 19) > > > > +/* > > + * VFIO_DEVICE_ATTACH_IOMMUFD_PT - _IOW(VFIO_TYPE, VFIO_BASE + 20, > > + * struct vfio_device_attach_iommufd_pt) > > + * > > + * Attach a vfio device to an iommufd address space specified by IOAS > > + * id or hw_pagetable (hwpt) id. > > + * > > + * Available only after a device has been bound to iommufd via > > + * VFIO_DEVICE_BIND_IOMMUFD > > + * > > + * Undo by VFIO_DEVICE_DETACH_IOMMUFD_PT or device fd close. > > + * > > + * @argsz: user filled size of this data. > > + * @flags: must be 0. > > + * @pt_id: Input the target id which can represent an ioas or a hwpt > > + * allocated via iommufd subsystem. > > + * Output the attached hwpt id which could be the specified > > + * hwpt itself or a hwpt automatically created for the > > + * specified ioas by kernel during the attachment. > > + * > > + * Return: 0 on success, -errno on failure. > > + */ > > +struct vfio_device_attach_iommufd_pt { > > + __u32 argsz; > > + __u32 flags; > > + __u32 pt_id; > > +}; > > + > > +#define VFIO_DEVICE_ATTACH_IOMMUFD_PT _IO(VFIO_TYPE, > VFIO_BASE + 20) > > + > > +/* > > + * VFIO_DEVICE_DETACH_IOMMUFD_PT - _IOW(VFIO_TYPE, VFIO_BASE + 21, > > + * struct vfio_device_detach_iommufd_pt) > > + * > > + * Detach a vfio device from the iommufd address space it has been > > + * attached to. After it, device should be in a blocking DMA state. > > + * > > + * Available only after a device has been bound to iommufd via > > + * VFIO_DEVICE_BIND_IOMMUFD. > > + * > > + * @argsz: user filled size of this data. > > + * @flags: must be 0. > > + * > > + * Return: 0 on success, -errno on failure. > > + */ > > +struct vfio_device_detach_iommufd_pt { > > + __u32 argsz; > > + __u32 flags; > > +}; > > + > > +#define VFIO_DEVICE_DETACH_IOMMUFD_PT _IO(VFIO_TYPE, > VFIO_BASE + 21) > > + > > /** > > * VFIO_DEVICE_GET_INFO - _IOR(VFIO_TYPE, VFIO_BASE + 7, > > * struct vfio_device_info)
