Re: Boot code awareness of the Hypervisor extension
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I agree with this one example. But I'm also trying to address the broader issue and ask the more general architecture-level question (that I originally stated), i.e. must new implementations that support newer arch extensions be able to run "old" boot code that is unaware of the new extensions and hence makes no effort to disable the next extensions in misa (which, btw, is not guaranteed by the spec to even be possible)? (And that boot code of course also makes no effort to initialize new CSR's that it is unaware of.)
If the answer is Yes, then the Privileged spec should state this architectural requirement (and each arch extension must make sure that it doesn't define anything in a way that prevents this from being achievable). If the answer is No, then the spec should state that there is not this requirement.
On Wed, Jun 3, 2020 at 1:13 PM Jonathan Behrens <behrensj@...> wrote: