Re: [Qemu-devel] [PATCH v5 00/10] Add support for VM Generation ID

[Igor Mammedov]

On Fri, 10 Feb 2017 19:27:21 +0100
Andreas Färber <address@hidden> wrote:

> Am 10.02.2017 um 19:18 schrieb Andrew Jones:
> > On Fri, Feb 10, 2017 at 05:16:59PM +0100, Igor Mammedov wrote:  
> >> On Fri, 10 Feb 2017 17:31:33 +0200
> >> "Michael S. Tsirkin" <address@hidden> wrote:
> >>  
> >>> On Fri, Feb 10, 2017 at 11:12:13AM +0100, Laszlo Ersek wrote:  
> >>>> On 02/05/17 10:11, address@hidden wrote:    
> >>>>> From: Ben Warren <address@hidden>  
> >> [...]
> >>  
> >>>>
> >>>> - or else, add another boolean property to vmgenid, one that parallels
> >>>> "dma-enabled" of "fw-cfg" precisely, in HW_COMPAT*. Then simply fail
> >>>> realize() when this property is false.    
> >>>
> >>> That's probably the easiest way. x-fw-cfg-dma-enabled.
> >>> Won't delay merging because of this, can be done with
> >>> patch on top.  
> >> (not related to this series)
> >>
> >> I've thought that there still were no consensus on x-foo prefix,
> >> not to mention that x- might be legitimate prefix for some properties.
> >>
> >> Maybe we should add a flag to property like INTERNAL_PROPERTY
> >> and then set it explicitly on for internal stuff.
> >>
> >> That way we could cleanly exclude internal properties from
> >>  -device foo,help and make sure that user won't set them from CLI.
> >> I'd even volunteer to add this API to Object  
> > 
> > Yes, please. I know of a property or two where it would be nice to
> > have that flag.  
> 
> Apart from documentation, what effect would such a flag have?
> 
> With QOM I don't really see "internal" as being a thing: Besides -device
> and the likes, we expose qom-set operation and -global option, and I
> don't think it makes sense to restrict the latter two. For -device,
> "realized" is a property I would classify as non-user maybe.
I'd propose to start with this flag hiding/forbiding usage of
property in following interfaces:

  * -device
  * -device foo,help
  * device_add

With docs mentioning that usage of hidden properties with
 -globals/qom-set isn't recommended.
  
> 
> Regards,
> Andreas
>