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

[Jack Schwartz <jack.schwartz@oracle.com>]

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
> <jack.schwartz@oracle.com> 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
>>>