Re: [PATCH v5 1/3] x86/viridian: Re-purpose the HVM parameter to be a feature mask

[Paul Durrant <Paul.Durrant@citrix.com>]

> -----Original Message-----
> From: Ian Jackson [mailto:Ian.Jackson@eu.citrix.com]
> Sent: 12 August 2014 16:26
> To: Paul Durrant
> Cc: xen-devel@lists.xen.org; Keir (Xen.org); Jan Beulich; Ian Campbell;
> Stefano Stabellini
> Subject: Re: [PATCH v5 1/3] x86/viridian: Re-purpose the HVM parameter to
> be a feature mask
> 
> Paul Durrant writes ("[PATCH v5 1/3] x86/viridian: Re-purpose the HVM
> parameter to be a feature mask"):
> > The viridian option in xl.cfg(5) has also been changed to a string list so
> > that the sets can be individually sepcified. For compatibility, if the
> > option is specified as a boolean, then a true (1) value will be translated
> > to a string list containing "base" and "freq".
> 
> This is correct, I think.  But the libxl API should be in numbers, not
> a string list.  Text to string conversion should be done in xl, not
> libxl.
> 
> I think that these flag values ought to be represented in the IDL, so
> that text-to-string conversion can be done automatically.
> 
> I looked at the existing IDL definitions and there don't seem to be
> any flags of this kind.  So I think this will involve a inventing new
> kind of IDL type.  It might be possible to adapt Enumeration.  It
> might be enough simply to provide a way to make an Enumeration whose
> corresponding typedef is to a uint32_t.
> 
> Does this make any kind of sense ?
> 

Yes, it does. I guess what we really want is an 'enumeration list' then - i.e. strings get translated via enumeration and then concatenated into a list.  Is there any precedent for such a thing?

  Paul

> Thanks,
> Ian.