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Re: [Xen-devel] Xen arm question



On Tue, 2013-12-17 at 20:00 +0530, Mj Embd wrote:
> On Tue, Dec 17, 2013 at 7:52 PM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> > On Tue, 2013-12-17 at 19:44 +0530, Mj Embd wrote:
> >> Hi,
> >> I have a trivial question, my knowledge of ARM is limited, pardon my
> >> ignorance. VTTBR  contains the vm id and the address of stage2 page
> >> table.
> >> AFAIK VTTBR is not banked across cores, what I mean here is the Core 0
> >> and Core 1 cannot see a different value of VTTBR.
> >>
> >> If this point is valid,
> >
> > It's not. Every core has it's own set of registers and coprocessors
> > (including mmu).
> >
> > In ARM old "banked" refers to different sets of registers available on
> > the same core depending on what mode it is in. for example supervisor
> > mode and usermode have their own SPSR register, so asking for spsr will
> > get you a different thing depending on which mode you are in.
> >
> > Ian.
> >
> >
> 
> Ok, that makes sense. May be i didnt read the ref manual that clearly.
> So I should assume VTTBR / VTCR / SCTLR / HSCTLR/ HCR is per core ?

Yes. Pretty much everything is per core, certainly all core registers
and cp registers (mmu etc are actually "coprocessors").

Ian.


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