Paolo Bonzini pbonzini at
Fri May 28 01:50:12 PDT 2021

On 28/05/21 03:06, Paul Walmsley wrote:
> Earlier this year, there was a post where someone asked on the RISC-V
> International lists whether the ISA architects were ready to freeze the H
> extension:

That someone was Anup. :)

> Many of the same points were made that you and Damien and Paolo have
> brought up on the Linux kernel mailing lists.  Two engineers working on
> the RISC-V ISA responded, representing two different companies.  They
> wrote in the thread above that it's "far from certain" that no changes
> will need to be need to be made, and that "it's a good (and necessary
> compromise)" to "[wait] a little longer to see [the AIA specification] at
> least stabilize".  So it sounds like there's still a diversity of opinions
> here.

Quoting from that thread: "So, in my own opinion, we're getting close. 
Not a few weeks, but not quarters either".  At this point it's been a 
quarter and no freezing is in sight.  The author was even pushing for 
stabilizing H together with pointer-masking, even though pointer masking 
is basically being developed with the assumption that H goes in before 
(it already includes CSRs like vsmte, vspmmask and vspmbase).

At this pace, I would be (gladly) surprised if the H extension is frozen 
within the next 6 months.


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