Re: CVS commit: src/lib/librumpuser

[Alexander Nasonov <alnsn%yandex.ru@localhost>]

Antti Kantee wrote:
> To be clear: the objection was to modifying a stable interface
> without coordination.  The hypercall interface is implemented in
> multiple places outside of the NetBSD tree, including by 3rd parties.

Stable interface in -current? How are you supposed to make any
significant changes then? 

As I stated in the private email to Antti, we need to support two
versions: stable for users and current for developers. Otherwise,
it will block a development of NetBSD if every time you need to
make a change in NetBSD-current, you have to wait for a rumpuser
bump for stable users even though many of them are outside of
NetBSD.

In other words, don't rely on NetBSD-current being 100% stable,
especially for users outside of NetBSD.

I don't know enough details about rump to be certain but would
splitting only rumpuser into two versions work? If there were two
versions of rumpuser I could tweak the makefile to build cpufunc.c
only if MKSLJIT=yes and it would solve the problem because MKSLJIT
is "no" by default on arm.

Another reason for splitting rumpuser is because some hypercalls can't
be implemented with POSIX API. I don't think we need to support Linux or
Solaris in NetBSD tree, especailly if it depends on OS-specific code.

> Think of it like changing the libc ABI: no matter the merits of
> the change itself (which they too remain to be discussed), it will
> be objected to.

I got an impression from your private email yesterday that the
approach is correct (you didn't say that librumpuser code must be
POSIX while the code I sent to you wasn't as it used NetBSD specific
sysarch syscall).

And because it was a pure addition of a new function and it didn't break
NetBSD build, I assumed that it's safe to add it. The only thing I
didn't do was rumpuser ABI version bump.

Alex