Re: [Qemu-devel] [PATCH 3/4] build: qemu-ga: fix VSS dependencies

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Quoting Paolo Bonzini (2015-09-07 05:48:27)
> 
> 
> On 28/08/2015 01:55, Michael Roth wrote:
> > Now we can build qemu-ga MSI package with:
> >   ./configure ...
> >   make qemu-ga.exe
> >   make msi
> > 
> > or simply:
> >   ./configure ...
> >   make msi
> 
> Shouldn't the latter have always worked?

Hmm, at the time of the patch I'm not sure, since out-of-tree builds
were broken with `make msi` until the recent:

  decdfbd qemu-ga: Fixed paths issue with MSI build

With that patch in place I noticed out-of-tree builds were still
broken:

  [mdroth@vm4 qemu-build-w64]$ ../w/qemu4.git/configure --enable-guest-agent --target-list=x86_64-softmmu --extra-cflags=-Wall --enable-guest-agent-msi --cross-prefix=x86_64-w64-mingw32- --with-vss-sdk=/home/mdroth/w/vss-win32/ && make msi
  ...
    AR    libqemustub.a
    LINK  qemu-ga.exe
    CXX   qga/vss-win32/requester.o
  ...
    CXX   qga/vss-win32/provider.o
    CXX   qga/vss-win32/install.o
    LINK  qga/vss-win32/qga-vss.dll
    WIXL  qemu-ga-x86_64.msi
  Couldn't find file /home/mdroth/qemu-build-w64/qga/vss-win32/qga-vss.tlb
  make: *** [qemu-ga-x86_64.msi] Error 1

For out-of-tree, qga-vss.tlb dependency gets met by QEMU tools target, which
is what motivated this patch.

But for in-tree builds, qga-vss.tlb is already present in working directory,
so it might have actually worked for that case.

So I may have misdiagnosed the root issue here: that *.tlb (not just
*.dll) needed to be added to MSI dependency list instead of being
assumed (via in-tree build or full qemu build with tools).

> 
> I think that if someone does "make qemu-ga.exe" they should *not* get
> the VSS files.  Perhaps we can add a Win32-specific phony qemu-ga target
> to build both qemu-ga.exe and the VSS files, but this patch's use of
> filter-out is a bit ugly.

I think it might make sense to re-de-couple VSS from qemu-ga.exe, but
I'm not sure I like the idea of making MSI target responsible for
VSS files. MSI is relatively new, but VSS support has been around for a
while when documentated install procedure for qemu-ga.exe was manually
copying files. MSI isn't the source of the issue, presumably everybody
distributing qemu-ga.exe in this manner was relying on the full build
to get the VSS files. But moving VSS completely to MSI means that use
case would break (whereas moving them to qemu-ga.exe would still work,
since qemu-ga.exe is build as part of default/full build)

I think the ideal solution is too keep things as they are with this
patch (previous working methods supported), but move to a new 'qemu-ga'
build target that just does the right thing on each platform:

  on posix:
    1) build 'qemu-ga' executable
  
  on mingw:
    1) build 'qemu-ga.exe' executable (no need to build .exe directly)
    2) build VSS if VSS supported/requested
    3) build MSI package if supported/requested (and include VSS files
       if VSS supported)

That would let us drop the wierd filtering, and bring the w32 build
process more inline with posix.

I'm not even sure if that's possible atm, but if that's reasonable I can
look into it as a follow-up (this series is merged already).

> 
> Paolo
>