Re: [Qemu-devel] -icount changes physical address assignments in QEMU 2.10/2.11

[alarson]

"Peter Maydell" <address@hidden> wrote on 04/05/2018 09:05:53 
AM:

> From: "Peter Maydell" <address@hidden>
> To: address@hidden
> Cc: "QEMU Developers" <address@hidden>
> Date: 04/05/2018 09:06 AM
> Subject: Re: [Qemu-devel] -icount changes physical address assignments 
in QEMU 2.10/2.11
> 
> On 22 March 2018 at 05:31,  <address@hidden> wrote:
> > Your patch (applied to 2.11 source release) changed the behavior
> > somewhat, but did not fix the problem.  Attached is a binary that when
> > run should show a CGA fontset and color bars.
> >
> > This command should "work":
> >
> > qemu-system-aarch64 -M virt,virtualization=on -cpu cortex-a53 -vga std
> > -device secondary-vga -device virtio-net,netdev=vlan0,addr=2 -kernel
> > icount-bug.bin -netdev user,id=vlan0
> >
> > If you add "-icount 2" the display will appear, but be mangled.
> >
> > I didn't spend too much time trimming the source code, so if you need
> > to step by step debug walking through the guest code, I'll have to
> > prune it down some more.
> >
> > For the record, the QEMU source I have is modified slightly to add ARM 
WFE
> > support, something I will submit once this is all straightened out,
> > but this bug appeared before I made that patch.
> 
> Hi; sorry for the delay in testing this. I've just tried your
> attached test image with current head of git QEMU (commit
> 0e87fdc966d05f4e5ad86, which is the 2.12.0-rc2 release candidate),
> and it gives me a correct display both with and without -icount 2.
> So I think we've fixed this bug, probably with the combination
> of commits 0790f86861079b19 and 87f963be66a3245, or possibly
> a75a52d62418da.
> 
> thanks
> -- PMM

Thank you for your help.

> I've just tried your attached test image ...

Curious.  I just downloaded qemu-2.12.0-rc2.tar.xz and built it using
Cygwin (a version from about a month ago) using mingw compilers
(mingw64-i686-gcc-g++ 6.4.0), and I still see the issue when the
resulting QEMU binary is run using -icount 2 against my test binary,
but not when run without -icount.  Here are the commands used:

../qemu-2.12.0-rc2/configure --python=/usr/bin/python \
   '--with-pkgversion=DDCI QEMU 2.12.0-rc2' \
   --prefix=/usr/local/qemu \
   --enable-sdl --with-sdlabi=2.0 \
   '--target-list=aarch64-softmmu ppc64-softmmu x86_64-softmmu' \
   --cross-prefix=i686-w64-mingw32-
/usr/bin/make -Otarget -j 8

Any suggestions of things to try?

If you think this is a build environment issue, I can try MSYS and
report my results.