Re: [Qemu-devel] [PATCH v2 0/9] configure: Fix softmmu --static linking

["Daniel P. Berrangé" <berrange@redhat.com>]

On Fri, Jun 14, 2019 at 12:07:09PM +0200, Philippe Mathieu-Daudé wrote:
> Hi,
> 
> Apparently QEMU static linking is slowly bitroting. Obviously it
> depends the libraries an user has installed, anyway it seems there
> are not much testing done.

Bitrotting implies that it actually worked in the first place.

AFAIK, configure has never been capable of auto-enabling the
correct set of libraries for static linking, if you have the
equiv dyn libraries present.

I always assumed that anyone who is static loinking QEMU is
passing a big long list of --disable-XXXX args to turn off
all the 3rd party libs for which they don't have a static
build present.

> This series fixes few issues, enough to build QEMU on a Ubuntu
> 18.04 host.
> 
> Peter commented on v1:
> 
>   The main reason for supporting static linking is so we can build
>   the user-mode emulators. Almost always the problems with
>   static linking the softmmu binaries and the tools are
>   issues with the distro's packaging of the static libraries
>   (pkg-config files which specify things that don't work for
>   static is a common one).
> 
>   So we could put in a lot of checking of "is what pkg-config
>   tells us broken". Or we could just say "we don't support static
>   linking for anything except the usermode binaries". We
>   should probably phase in deprecation of that because it's
>   possible somebody's using it seriously, but it seems like
>   a fairly weird thing to do to me.
> 
> I share his view on this (restricting static linking to qemu-user)
> but since the work was already done when I read his comment, I still
> send the v2.

I share Peter's view that we ought to restrict static linking to be
allowed exclusively for user-mode-only builds of QEMU. This is a use
case with a compelling reason to need static builds. It is not bitrotting
as the main distros all do a static user-mode only QEMU build, alongside
the main everything, fully dynamic build.

Static builds of system emulators & other tools get essentially no
testing by developers, distros, or our CI systems. If they do work
it is largely by luck, and likely requires the user to pass many
--disable-XXX flags. While your patches do make configure a bit
nicer in this respect, if we're going to deprecate static builds
of non-user-mode parts, then making static builds easier feels
undesirable.

Lets just get a deprecation warning in right now for this imminent
release.

Regards,
Daniel
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