Re: [Qemu-devel] [PATCH QEMU v1 0/4] multiboot: bss_end_addr can be zero / cleanup

[Jack Schwartz]

Hi Anatol, Daniel and Kevin.

On 01/19/18 10:36, Anatol Pomozov wrote:
> Hello Jack
>
> On Wed, Jan 17, 2018 at 12:06 PM, Jack Schwartz
> <address@hidden> wrote:
> > Hi Kevin and Anatol.
> >
> > Kevin, thanks for your review.
> >
> > More inline below...
> >
> > On 01/15/18 07:54, Kevin Wolf wrote:
> > > Am 21.12.2017 um 18:25 hat Jack Schwartz geschrieben:
> > > > Properly account for the possibility of multiboot kernels with a zero
> > > > bss_end_addr.  The Multiboot Specification, section 3.1.3 allows for
> > > > kernels without a bss section, by allowing a zeroed bss_end_addr
> > > > multiboot
> > > > header field.
> > > >
> > > > Do some cleanup to multiboot.c as well:
> > > > - Remove some unused variables.
> > > > - Use more intuitive header names when displaying fields in messages.
> > > > - Change fprintf(stderr...) to error_report
> > > There are some conflicts with Anatol's (CCed) multiboot series:
> > > https://lists.nongnu.org/archive/html/qemu-devel/2017-10/msg03003.html
> > >
> > > None if these should be hard to resolve, but it would be good if you
> > > could agree with each other whose patch series should come first, and
> > > then the other one should be rebased on top of that.
> > Anatol,
> >
> > from my side, there are pros and cons to either patch set going in first,
> > but advantages to either are pretty negligible.  Pro for you going first: I
> > can use the constants you will define in header files.  Pro for me going
> > first: your merge should be about the same as if you went first (since my
> > changes are small, more localized and affect only multiboot.c) and my merge
> > will be easier.
> >
> > What are your thoughts?
> Please move ahead with your patches. I'll rebase my changes on top of yours.
OK.  I'm consulting with my company's legal department and waiting for 
their approvals for delivery of a test "kernel".  I'll get in touch will 
everyone once I have an answer about that.  I anticipate about a week 
before taking next steps to deliver.

Kevin and Daniel, thanks for your inputs on this issue (different 
subthread), which I have forwarded to our legal department for review.

    Thanks,
    Jack
> > > Testing:
> > >     1) Ran the "make check" test suite.
> > >     2) Booted multiboot kernel with bss_end_addr=0.  (I rolled my own
> > >        grub multiboot.elf test "kernel" by modifying source.)  Verified
> > >        with gdb that new code that reads addresses/offsets from multiboot
> > >        header was accessed.
> > >     3) Booted multiboot kernel with non-zero bss_end_addr.
> > >     4) Uncommented DEBUG_MULTIBOOT in multiboot.c and verified messages
> > > worked.
> > >     5) Code has soaked in an internal repo for two months.
> > > Can you integrate your test kernel from 2) in tests/multiboot/ so we can
> > > keep this as a regression test?
> > Kevin and alias,
> >
> > Before I proceed with adding my multiboot test file, I'll clarify here that
> > I started with a version from the grub2 tree.  In that file I expanded a
> > header file, also from the same tree.  Neither file had any license header,
> > though the tree I got them from (Dated October 2017) contains the GNU GPLv3
> > license file.
> >
> > I'll need to check with my company before I can say I can deliver this file.
> > If I deliver it, I'll add a header stating the GPL license, that it came
> > from grub2 and to check its repository for contributors.
> > > > Jack Schwartz (4):
> > > >     multiboot: bss_end_addr can be zero
> > > >     multiboot: Remove unused variables from multiboot.c
> > > >     multiboot: Use header names when displaying fields
> > > >     multiboot: fprintf(stderr...) -> error_report()
> > > Apart from the conflicts, the patches look good to me.
> >      Thanks,
> >      Jack
> > > Kevin