Re: [Xen-devel] (v2) Design proposal for RMRR fix

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> Sent: Monday, January 12, 2015 7:37 PM
> 
> >>> On 12.01.15 at 12:22, <kevin.tian@xxxxxxxxx> wrote:
> >>  From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> >> Sent: Monday, January 12, 2015 6:23 PM
> >> One of my main problems with all you recent argumentation here
> >> is the arbitrary use of the 1Gb boundary - there's nothing special
> >> in this discussion with where the boundary is. Everything revolves
> >> around the (undue) effect of report-all on domains not needing all
> >> of the ranges found on the host.
> >>
> >
> > I'm not sure which part of my argument is not clear here. report-all
> > would be a problem here only if we want to fix all the conflictions
> > (then pulling unnecessary devices increases the confliction possibility)
> > in the domain builder. but if we only fix reasonable ones (e.g. >3GB)
> > while warn other conflictions (e.g. <3G) in domain builder (let later
> > assignment path to actually fail if confliction does matter),
> 
> And have no way for the user to (securely) avoid that failure. Plus
> the definition of "reasonable" here is of course going to be arbitrary.
> 
> Jan

actually here I didn't get your point then. It's your proposal to make 
reasonable assumption like below:

---
d) Move down the lowmem RAM/MMIO boundary so that a single,
contiguous chunk of lowmem results, with all other RAM moving up
beyond 4Gb. Of course RMRRs below the 1Mb boundary must not be
considered here, and I think we can reasonably safely assume that
no RMRRs will ever report ranges above 1Mb but below the host
lowmem RAM/MMIO boundary (i.e. we can presumably rest assured
that the lowmem chunk will always be reasonably big).
---

Thanks
Kevin

> 
> > then we
> > don't need to solve all conflictions in domain builder (if say 1G example
> > fixing it may instead reduce lowmem greatly) and then report-all
> > may just add more warnings than report-sel for unused devices.
> >
> > Thanks
> > Kevin
> 
> 


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