Re: [Qemu-devel] [PATCH 0/8] tcg/interpreter: Add TCG + interpreter for bytecode (virtual machine)

[Stefan Weil <weil@mail.berlios.de>]

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Am 18.09.2011 15:00, schrieb Blue Swirl:
> On Sun, Sep 18, 2011 at 12:46 PM, malc <av1474@comtv.ru> wrote:
>> On Sun, 18 Sep 2011, Blue Swirl wrote:
>>
>>> On Sun, Sep 18, 2011 at 10:49 AM, malc <av1474@comtv.ru> wrote:
>>>> On Sun, 18 Sep 2011, Blue Swirl wrote:
>>>>
>>>>> On Sat, Sep 17, 2011 at 7:59 PM, Stefan Weil 
>>>>> <weil@mail.berlios.de> wrote:
>>>>>> Hello,
>>>>>>
>>>>>> these patches add a new code generator (TCG target) to qemu.
>>>>>>
>>>>>> Unlike other tcg target code generators, this one does not generate
>>>>>> machine code for some cpu. It generates machine independent bytecode
>>>>>> which is interpreted later. That's why I called it TCI (tiny code
>>>>>> interpreter).
>>>>>>
>>>>>> I wrote most of the code two years ago and included feedback and
>>>>>> contributions from several QEMU developers, notably TeleMan,
>>>>>> Stuart Brady, Blue Swirl and Malc. See the history here:
>>>>>> http://lists.nongnu.org/archive/html/qemu-devel/2009-09/msg01710.html
>>>>>>
>>>>>> Since that time, I used TCI regularly, added small fixes and 
>>>>>> improvements
>>>>>> and rebased it to latest QEMU. Some versions were tested using
>>>>>> ARM (emulated and real), PowerPC (emulated) and MIPS (emulated) 
>>>>>> hosts,
>>>>>> but normally I run it on i386 and x86_64 hosts.
>>>>>>
>>>>>> I'd appreciate to see TCI in QEMU 1.0.
>>>>>>
>>>>>> Regards,
>>>>>> Stefan Weil
>>>>>>
>>>>>> The patches 2 and 4 are optional, patch 8 is only needed for running
>>>>>> TCI on a PowerPC host.
>>>>>
>>>>> I think patches 1 to 4 and 8 could be applied soon as they are now,
>>>>> they should benefit plain TCG too. I had some comments to other
>>>>> patches, but otherwise everything looks great.
>>>>
>>>> Hold the horses until Stefan settles the licensing issues.
>>>
>>> Which issues? For which patches?
>>>
>>
>> Read tcg/LICENSE.
>
> "All the files in this directory and subdirectories are released under
> a BSD like license (see header in each file). No other license is
> accepted."
>
> The wording of the file should be changed to list the files for which
> the BSD like license applies (and for which no other license is
> accepted), the file can't stop us adding new files with different
> licenses.

Thanks for all feedback given.

These license issues delayed my further working on tci.
In the meantime, I asked Fabrice Bellard. Here is his answer:

    "Sorry but I no longer care about the license of this code.
    But if I was still in charge of the project,
    I would clearly refuse any non BSD code in TCG. "

Although I agree with Blue's opinion given above, I also
want to respect Fabrice.

Therefore I suggest these changes:

* tcg/bytecode is moved to tcg/tci, and I change the license to BSD.

* The interpreter is moved from tcg/tci.c to tci.c and remains GPL.
   It is no longer in TCG, so there is no conflict with tcg/LICENSE.

This might seem to be a trick, but in some way it is similar to the
other tcg target implementations: the code generator is always BSD,
and the generated code is run on a system with a different license.

Comments welcome. As soon as there is a consensus on the way how tci
can be integrated I'll continue with patch series v2.

Patches 1 to 4 could be applied immediately (that would reduce the
size of the new series).

Kind regards,

Stefan Weil


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