Re: [PATCH v1 2/8] iommu: Introduce a new iommu_group_replace_domain() API

[Baolu Lu]

On 2023/2/3 3:14, Nicolin Chen wrote:
> On Thu, Feb 02, 2023 at 06:21:20PM +0800, Baolu Lu wrote:
> > External email: Use caution opening links or attachments
> >
> >
> > On 2023/2/2 15:05, Nicolin Chen wrote:
> > > +/**
> > > + * iommu_group_replace_domain - replace the domain that a group is attached to
> > > + * @new_domain: new IOMMU domain to replace with
> > > + * @group: IOMMU group that will be attached to the new domain
> > > + *
> > > + * This API allows the group to switch domains without being forced to go to
> > > + * the blocking domain in-between.
> > > + *
> > > + * If the attached domain is a core domain (e.g. a default_domain), it will act
> > > + * just like the iommu_attach_group().
> > I am not following above two lines. Why and how could iommufd set a
> > core domain to an iommu_group?
> Perhaps this isn't the best narrative. What it's supposed to say
> is that this function acts as an iommu_attach_group() call if the
> device is "detached", yet we have changed the semantics about the
> word "detach". So, what should the correct way to write such a
> note?

How could this interface be used as detaching a domain from a group?
Even it could be used, doesn't it act as an iommu_detach_group()?

Best regards,
baolu