Re: [Xen-devel] [PATCH 3/5] xen: virq, remove VIRQ_XC_RESERVED

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2012-08-06 at 16:01 +0100, Jean Guyader wrote:
> On 6 August 2012 15:56, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> > On Mon, 2012-08-06 at 15:46 +0100, Jean Guyader wrote:
> >> On 6 August 2012 09:10, Jan Beulich <JBeulich@xxxxxxxx> wrote:
> >> >>>> On 03.08.12 at 21:50, Jean Guyader <jean.guyader@xxxxxxxxxx> wrote:
> >> >> VIRQ_XC_RESERVED was reserved for V4V but we have switched
> >> >> to event channels so this place holder is no longer required.
> >> >
> >> > I'm fine with this change, but is a future re-use of the value indeed
> >> > not going to cause problems on XenServer (or wherever else this
> >> > is patch set coming from)?
> >> >
> >>
> >> That may need to be confirmed but I don't think XenServer is using v4v
> >> yet
> >
> > I think Jan probably meant XenClient (i.e. that being the place where
> > v4v is already deployed).
> >
> > There's no harm in keeping this # reserved indefinitely, with a suitable
> > comment, I think? The only reason not to would be if this address space
> > was limited, but I don't think that is the case with VIRQs
> >
> >
> 
> I think if XenClient rebase to a new version of Xen we will probably
> use the version of
> v4v that comes with it and we will not try to rebase the old code on
> the newer Xen.

I think Jan's concern was if a current client runs on some future
version of Xen which has reused that VIRQ for something else, some sort
of weirdness would probably ensue?

Probably not as bad for a VIRQ as reusing a hypercall number...


> 
> But if you think we should keep it I don't mind.
> 
> Jean



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel