Messages in this thread | | | Date | Mon, 28 Feb 2022 14:05:20 -0400 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v6 09/10] hisi_acc_vfio_pci: Add support for VFIO live migration |
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On Mon, Feb 28, 2022 at 06:01:44PM +0000, Shameerali Kolothum Thodi wrote:
> +static long hisi_acc_vf_save_unl_ioctl(struct file *filp, > + unsigned int cmd, unsigned long arg) > +{ > + struct hisi_acc_vf_migration_file *migf = filp->private_data; > + loff_t *pos = &filp->f_pos; > + struct vfio_device_mig_precopy precopy; > + unsigned long minsz; > + > + if (cmd != VFIO_DEVICE_MIG_PRECOPY) > + return -EINVAL;
ENOTTY
> + > + minsz = offsetofend(struct vfio_device_mig_precopy, dirty_bytes); > + > + if (copy_from_user(&precopy, (void __user *)arg, minsz)) > + return -EFAULT; > + if (precopy.argsz < minsz) > + return -EINVAL; > + > + mutex_lock(&migf->lock); > + if (*pos > migf->total_length) { > + mutex_unlock(&migf->lock); > + return -EINVAL; > + } > + > + precopy.dirty_bytes = 0; > + precopy.initial_bytes = migf->total_length - *pos; > + mutex_unlock(&migf->lock); > + return copy_to_user((void __user *)arg, &precopy, minsz) ? -EFAULT : 0; > +}
Yes
And I noticed this didn't include the ENOMSG handling, read() should return ENOMSG when it reaches EOS for the pre-copy:
+ * During pre-copy the migration data FD has a temporary "end of stream" that is + * reached when both initial_bytes and dirty_byte are zero. For instance, this + * may indicate that the device is idle and not currently dirtying any internal + * state. When read() is done on this temporary end of stream the kernel driver + * should return ENOMSG from read(). Userspace can wait for more data (which may + * never come) by using poll.
Jason
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