Re: [dpdk-dev] [PATCH v4] eal/cpuflags: add x86 based cpu flags

["Laatz, Kevin" <kevin.laatz@intel.com>]

 
> (replying this time to the list)
> 
> On 25/04/2020 17:04, Thomas Monjalon wrote:
> > 16/04/2020 13:00, Kevin Laatz:
> >> This patch adds CPU flags which will enable the detection of ISA
> >> features available on more recent x86 based CPUs.
> > [...]
> >> --- a/devtools/libabigail.abignore
> >> +++ b/devtools/libabigail.abignore
> >> +; Ignore this enum update as it should not be allocated by the
> >> +application [suppress_type]
> >> +	type_kind = enum
> >> +	name = rte_cpu_flag_t
> >> +	changed_enumerators = RTE_CPUFLAG_NUMFLAGS
> >
> > The justification is not correct.
> > The application is allowed to use RTE_CPUFLAG_NUMFLAGS in array
> allocation.
> > But no API is returning a CPU flag, so the new flags will remain
> > unknown to the application.
> >
> > However, there is a behaviour change:
> > The functions rte_cpu_get_flag_name() and rte_cpu_get_flag_enabled()
> > will now accept new values, which were previously considered as an error.
> > Is it an ABI breakage? I would say no.
> 
> We saw something similar with the Cryptodev's rte_crypto_sym_xform_type
> also.
> Libabigail appears to be particularly sensitive to changes to enumerations.
> Leaving it to the user to decide if there is a problem.
> 
> I am seeing a bit of weirdness though between versions of libabigail.
> 1.7.1 seems to fine with the change, however 1.2 is reporting an issue.
> 
> Kevin - what version are you using?

I'm using version 1.6.0

> 
> >
> > PS: Who is REALLY maintaining the ABI?
> > We really miss someone who carefully check all these things, and take
> > care of the doc and tooling.
> >
> >
> 
> I would say that I am missing these changes to libabigail.ignore, which would
> be useful.
> Should we consolidate the ABI Policy and ABI Versioning sections of the
> MAINTAINERS file?