Re: [Xen-devel] [PATCH v7] sndif: add ABI for Para-virtual sound

[Lars Kurth <lars.kurth.xen@xxxxxxxxx>]

> On 17 Mar 2015, at 11:40, Ian Campbell <ian.campbell@xxxxxxxxxx> wrote:
> 
> On Thu, 2015-03-12 at 18:14 +0000, Lars Kurth wrote:
>> Hi,I nearly missed this. Please make sure you forward stuff and change
>> the headline if you want me to look into things. Otherwise I may miss
>> it.
> 
> Sure, I'll try and remember.
> 
> FYI before Ian J went away he mentioned that he had raised some
> questions/issues (either on this or a previous version) which had not
> yet been answered (or maybe not answered to his satisfaction, I'm not
> sure) but that if those were addressed he would take a look with a view
> to acking the interface for inclusion in xen.git.

OK. So this means there are some concrete lose ends, which need to be followed 
up on. I also remember that there was a discussion on how we should specify 
protocols, which does not appear to have fully concluded either. 

>> 
>> Would this work as a way forward?
> 
> I think the main things which is missing is some decision as to the the
> point at which we would consider the ABI for a PV protocol fixed, i.e.
> to be maintained in a backwards compatible manner from then on. 

What do we do with new APIs in such situations? It would appear that there is 
some commonality in how we would handle a protocols and an API. I am assuming 
APIs such as new hypercalls don't immediately become fixed and backwards 
compatible. 

> That's of particular importance when one end of the pair is implemented
> in external projects (e.g. OS driver frontends). If the interface is not
> declared stable then changes would be allowed which would invalidate
> those drivers.

I understand that external projects may have different rules to us, which may 
cause problems. If this was the case in this instance, this would be an 
argument for using a xen project tree as a temporary location until we have 
declared the protocol ABI stable.

Regards
Lars


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel