Re: [PATCH RFCv2 07/13] iommufd: Implement sw_msi support natively

[Jason Gunthorpe]

On Fri, Jan 10, 2025 at 07:32:23PM -0800, Nicolin Chen wrote:

> +/*
> + * FIXME: when a domain is removed any ids that are not in the union of
> + * all still attached devices should be removed.
> + */

I've been thinking about this, maybe we can just delete the comment.

It is thinking about is the case where you attach a domain to device
A, then B, then detach B. If there are multiple ITS pages then B's
page will remain accessible to A.

However, A had access to B's page already and it was perfectly fine,
so why do we need to revoke it?

The logic is fine to keep track of this, so I think we can just let it
be. ITS pages populate in a lazy way, but are permanent once
populated.

Jason