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Re: [Qemu-devel] [RFC PATCH v1 11/13] spapr: Initialize hotplug memory a
From: |
Bharata B Rao |
Subject: |
Re: [Qemu-devel] [RFC PATCH v1 11/13] spapr: Initialize hotplug memory address space |
Date: |
Tue, 17 Feb 2015 09:30:08 +0530 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Mon, Feb 16, 2015 at 03:56:24PM +1100, David Gibson wrote:
> > > > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> > > > index ae8b4e1..64681c4 100644
> > > > --- a/include/hw/ppc/spapr.h
> > > > +++ b/include/hw/ppc/spapr.h
> > > > @@ -482,6 +482,9 @@ struct sPAPRTCETable {
> > > > #define TIMEBASE_FREQ 512000000ULL
> > > > #define SPAPR_MIN_MEMORY_BLOCK_SIZE (1 << 28) /* 256MB */
> > > >
> > > > +/* Support a min of 1TB hotplug memory assuming 256MB per slot */
> > > > +#define SPAPR_MAX_RAM_SLOTS (1ULL << 12)
> > >
> > > Is this constraint arbitrary, or does it come from something in PAPR+?
> >
> > Arbitrary max, not defined by PAPR.
>
> Ok. Why do we need a fixed maximum value? I don't see this used to
> size any arrays..
The max slots limit comes from x86 where ACPI limits the max dimm
devices to 256. Since pc-dimm implementation requires this max, I came
up with the above value for ppc.
Regards,
Bharata.