Re: [PATCH] CHANGELOG.md: Make PV shim smaller by factoring out HVM-specific shadow code

[Jan Beulich <jbeulich@xxxxxxxx>]

On 31.03.2021 16:30, George Dunlap wrote:
> 
> 
>> On Mar 31, 2021, at 3:06 PM, Jan Beulich <jbeulich@xxxxxxxx> wrote:
>>
>> On 31.03.2021 16:00, George Dunlap wrote:
>>>
>>>
>>>> On Mar 31, 2021, at 2:54 PM, Jan Beulich <jbeulich@xxxxxxxx> wrote:
>>>>
>>>> On 31.03.2021 15:52, Ian Jackson wrote:
>>>>> George Dunlap writes ("Re: [PATCH] CHANGELOG.md: Make PV shim smaller by 
>>>>> factoring out HVM-specific shadow code"):
>>>>>> I don’t understand why the two of you are downplaying your work so much. 
>>>>>> Yes, these are all only incremental improvements; but they are 
>>>>>> improvements; and the cumulative effect of loads of incremental 
>>>>>> improvements can be significant.  Communicating to people just what the 
>>>>>> nature of all these incremental improvements are is important.
>>>>>
>>>>> I agree with George here.
>>>>>
>>>>> There ae a number of reasons why behind-the-scenes work with little
>>>>> (intentional) user-visible impact are useful to note in the
>>>>> CHANGELOG.md.  With my Release Manager hat on I would like to see, for
>>>>> example,
>>>>>
>>>>>>> + - Factored out HVM-specific shadow code, allowing PV shim to be 
>>>>>>> slimmer
>>>>>
>>>>> something about htis work in the CHANGELOG.md.
>>>>>
>>>>> IDK precisely, and I don't think George does either, what a good and
>>>>> accurate statement is.  But I guess we will go with the text above if
>>>>> we don't get something better.
>>>>
>>>> At the very least the part after the comma ought to be deleted. As
>>>> said in an earlier reply, at least the shim default config disables
>>>> shadow code anyway, so the factoring out has no effect there.
>>>
>>> Thanks.  So when you wrote the series, what was your motivation?  Did you 
>>> have a particular technical outcome in mind?  Or did it just bother you 
>>> that there was HVM-only code in a PV-only build? :-)
>>
>> What bothers me are more the implications - it being rather hard in
>> many cases, and in particular in shadow code, to be able to tell what
>> paths are involved in the handling of what kind(s) of guests. This
>> has made more time consuming investigation of (suspected) misbehavior
>> in more than one case.
> 
> OK, so how about:
> 
> - Factored out HVM-specific shadow code, improving code clarity and reducing 
> the size of PV-only hypervisor builds

This sounds okay to me.

Thanks, Jan