> From: Tian, Kevin <kevin.tian@xxxxxxxxx>
> Sent: Wednesday, February 22, 2023 3:26 PM
>
> > From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> > Sent: Tuesday, February 21, 2023 11:48 AM
> >
> > /*
> > * We can't let userspace give us an arbitrarily large buffer to copy,
> > - * so verify how many we think there could be. Note groups can
> have
> > - * multiple devices so one group per device is the max.
> > + * so verify how many we think there could be. Note user may
> > provide
> > + * a set of groups, group can have multiple devices so one group per
> > + * device is the max.
>
> well this change doesn't include cdev
For cdev, it should be the number of devices. 😊
>
> > @@ -1320,7 +1321,7 @@ static int vfio_pci_ioctl_pci_hot_reset(struct
> > vfio_pci_core_device *vdev,
> > }
> >
> > /* Ensure the FD is a vfio FD.*/
> > - if (!vfio_file_is_valid(file)) {
> > + if (!vfio_file_is_device_opened(file)) {
> > fput(file);
> > ret = -EINVAL;
> > break;
>
> that function is not just for checking device.
>
> Probably rename it to vfio_file_is_reset_valid().
How about vfio_file_is_resettable()?
> btw this patch is insufficient to handle device fd. The current logic
> requires every device in the dev_set covered by provided fd's:
>
> static bool vfio_dev_in_groups(struct vfio_pci_core_device *vdev,
> struct vfio_pci_group_info *groups)
> {
> unsigned int i;
>
> for (i = 0; i < groups->count; i++)
> if (vfio_file_has_dev(groups->files[i], &vdev->vdev))
> return true;
> return false;
> }
>
> Presumably when cdev fd is provided above should compare iommu
> group of the fd and that of the vdev. Otherwise it expects the user
> to have full access to every device in the set which is impractical.
Yes. This can be done by checking the device->vfio_group->iommu_group.
But group code may be compiled out eventually. If CONFIG_VFIO_GROUP==n.
needs to use iommu_group_get() to get iommu_group and compare.
btw. I have a doubt about if it is possible that the iommu_group
can disappear during the reset. If yes, maybe better store iommu_group
in vfio_device in the vfio_register_group_dev() path if CONFIG_VFIO_GROUP
is not enabled.
Regards,
Yi Liu
