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

[Anatol Pomozov]

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.

>>
>> 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
>>
>