RE: [RFC v3 13/25] intel_iommu: modify x-scalable-mode to be string option

[Liu, Yi L]

> From: Peter Xu <address@hidden>
> Sent: Thursday, February 13, 2020 12:06 AM
> To: Liu, Yi L <address@hidden>
> Subject: Re: [RFC v3 13/25] intel_iommu: modify x-scalable-mode to be string
> option
> 
> On Wed, Feb 12, 2020 at 07:28:24AM +0000, Liu, Yi L wrote:
> > > From: Peter Xu <address@hidden>
> > > Sent: Wednesday, February 12, 2020 3:44 AM
> > > To: Liu, Yi L <address@hidden>
> > > Subject: Re: [RFC v3 13/25] intel_iommu: modify x-scalable-mode to
> > > be string option
> > >
> > > On Wed, Jan 29, 2020 at 04:16:44AM -0800, Liu, Yi L wrote:
> > > > From: Liu Yi L <address@hidden>
> > > >
> > > > Intel VT-d 3.0 introduces scalable mode, and it has a bunch of
> > > > capabilities related to scalable mode translation, thus there are
> > > > multiple
> > > combinations.
> > > > While this vIOMMU implementation wants simplify it for user by
> > > > providing typical combinations. User could config it by
> > > > "x-scalable-mode" option. The usage is as below:
> > > >
> > > > "-device intel-iommu,x-scalable-mode=["legacy"|"modern"]"
> > >
> > > Maybe also "off" when someone wants to explicitly disable it?
> >
> > emmm, I  think x-scalable-mode should be disabled by default. It is
> > enabled only when "legacy" or "modern" is configured. I'm fine to add
> > "off" as an explicit way to turn it off if you think it is necessary.
> > :-)
> 
> It's not necessary.  It'll be necessary when we remove "x-" and change the
> default value.  However it'll always be good to provide all options 
> explicitly in the
> parameter starting from when we design it, imho.  It's still experimental, 
> so...
> Your call. :)

Got it. Let me add it in next version. 😊

Regards,
Yi Liu