Re: [PATCH 1/5] x86/cpu-policy: Infrastructure for the AMD SVM and SEV leaves

[George Dunlap <george.dunlap@xxxxxxxxx>]

On Tue, Apr 30, 2024 at 2:25 PM Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
>
> On 30/04/2024 1:45 pm, Jan Beulich wrote:
> > On 29.04.2024 17:16, Andrew Cooper wrote:
> >> Allocate two new feature leaves, and extend cpu_policy with the non-feature
> >> fields too.
> >>
> >> The CPUID dependency between the SVM bit on the whole SVM leaf is
> >> intentionally deferred, to avoid transiently breaking nested virt.
> > In reply to this I meant to ask that you at least add those dependencies in
> > commented-out form, such that from looking at gen-cpuid.py it becomes clear
> > they're intentionally omitted. But you don't add feature identifiers either,
> > making dependencies impossible to express. Maybe this sentence was really
> > meant for another of the patches? (Then my request would actually apply
> > there.)
>
> This is necessary because c/s 4f8b0e94d7ca is buggy.  Notice how it puts
> an edit to the policy object in the middle of a block of logic editing
> the featureset, which ends with writing the featureset back over the
> policy object.
>
> And it's not the first outstanding problem from what is a very small
> number of nested-virt patches so far...

I specifically raised this on the x86 maintainers call, and you said
to go ahead with it.

 -George