Re: [PATCH 09/12] x86/shadow: Rework write_atomic() call in shadow_write_entries()

[Nicola Vetrini <nicola.vetrini@bugseng.com>]

On 2026-02-25 13:14, Andrew Cooper wrote:
> On 23/02/2026 7:26 am, Roberto Bagnara wrote:
>> On 20/02/26 22:46, Andrew Cooper wrote:
>>> Eclair complains of a side effect in a sizeof() expression (R13.6).
>> 
>> I disagree with comments of the form "Eclair complains"
> 
> We use the same phrasing with other tools too, but I can change it to
> "reports" which I suppose is a more neutral term.
> 
>> 
>> Note that in recent versions of MISRA C that rule is no longer
>> mandatory.  More generally, note also that, IMHO, switching to
>> a more modern version of MISRA C would simplify compliance.
> 
> Ok.  Making things simpler for compliance sounds like a good thing. 
> What would this entail?
> 
> Presumably we've got to adapt to all changes in this newer revision of
> MISRA C.
> 
> ~Andrew

Most likely new violations on new non-clean guidelines, generally rules 
for features that were standardized in C11/C18 and were previously 
widely available extensions (e.g. _Noreturn, _Alignof, threads, ...), 
alongside some minor changes in existing ones, such as the 
classification change mentioned by Roberto. The exact impact depends on 
the target MISRA revision, however. Making an experiment should be only 
a matter of s/MC3A2/MC4/ (or whichever MISRA revision is chosen: MC4 in 
ECLAIR refers to the latest published MISRA revision, that is, MISRA 
C:2025. Perhaps also a few regressions (as in newly introduced 
violations) on clean ones, but I do not expect the results to be 
radically different.

Side note here: are the efforts to make Xen compile with -stc=c11/gnu11 
still ongoing? I say this because any MISRA revision other than the one 
currently used by Xen by default is based on C11, as it introduces 
guidelines for C11/C18 features. Not that this would matter a whole lot 
for Xen, but it is something to consider in the broader picture.

-- 
Nicola Vetrini, B.Sc.
Software Engineer
BUGSENG (https://bugseng.com)
LinkedIn: https://www.linkedin.com/in/nicola-vetrini-a42471253