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

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2015-01-12 at 12:13 +0000, George Dunlap wrote:
> On Mon, Jan 12, 2015 at 11:22 AM, Tian, Kevin <kevin.tian@xxxxxxxxx> wrote:
> >> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> >> Sent: Monday, January 12, 2015 6:23 PM
> >>
> >> >>> On 12.01.15 at 11:12, <kevin.tian@xxxxxxxxx> wrote:
> >> >>  From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> >> >> Sent: Monday, January 12, 2015 6:09 PM
> >> >>
> >> >> >>> On 12.01.15 at 10:56, <kevin.tian@xxxxxxxxx> wrote:
> >> >> > the result is related to another open whether we want to block guest
> >> >> > boot for such problem. If 'warn' in domain builder is acceptable, we
> >> >> > don't need to change lowmem for such rare 1GB case, just throws
> >> >> > a warning for unnecessary conflictions (doesn't hurt if user doesn't
> >> >> > assign it).
> >> >>
> >> >> And how would you then deal with the one guest needing that
> >> >> range reserved?
> >> >
> >> > if guest needs the range, then report-all or report-sel doesn't matter.
> >> > domain builder throws the warning, and later device assignment will
> >> > fail (or warn w/ override). In reality I think 1GB is rare. Making such
> >> > assumption to simplify implementation is reasonable.
> >>
> >> 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), 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.
> 
> You keep saying "report-all" or "report-sel", but I'm not 100% clear
> what you mean by those.

Is the distinction between "all reserved areas" and "only (selectively)
those which are related to an RMRR"? That's how I've been reading it...

Ian.


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