Re: [PATCH 0/7] x86: Address Space Isolation, part 1: per-domain area mapping rework

[George Dunlap <gwd@xxxxxxxxxxxxxx>]

On Fri, Aug 21, 2026 at 4:17 PM George Dunlap <gwd@xxxxxxxxxxxxxx> wrote:

> Ultimately, I think there's a lot of wisdom in the saying, "Premature
> optimization is the root of all evil."  As I said, it's certainly
> right to be on our guard against adding things to xenheap, and look at
> alternatives; but we're nowhere near the point where we need to say,
> "Absolutely nothing added, regardless of the cost."  The design here
> is not locking us into the pages long-term; alternate designs have a
> significant cost in terms of authoring, reviewing, code complexity and
> maintenance, and code performance.

To get a sense of how much this approach simplifies things, look at
how patch 1 of this series simplified create_perdomain_mapping; and
look at how much simpler patch 2 is compared to Roger's implementation
[1].  The xenheap option is way easier to review and maintain.

 -George

[1] https://marc.info/?l=xen-devel&m=173634640624259