From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [RFC 5/5] KVM: ARM: Access all registers via KVM_GET_ONE_REG/KVM_SET_ONE_REG.
Date: Sat, 01 Sep 2012 02:16:57 -0700
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References: <877gsia8rm.fsf@rustcorp.com.au> <87pq6a8toa.fsf@rustcorp.com.au> <CAFEAcA_VZw-=v4hTm=Z2FK3aymxtLb77FXzq9yDC-n2bbGMnrg@mail.gmail.com> <87pq69sgnk.fsf@rustcorp.com.au>
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Cc: Peter Maydell <peter.maydell@linaro.org>,
	Christoffer Dall <c.dall@virtualopensystems.com>,
	Alexander Graf <agraf@suse.de>, kvmarm@lists.cs.columbia.edu,
	kvm-devel <kvm@vger.kernel.org>
To: Rusty Russell <rusty.russell@linaro.org>
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On 08/29/2012 11:21 AM, Rusty Russell wrote:
> >> +       /* Coprocessor 0 means we want a core register. */
> >> +       if ((u32)reg->id >> KVM_REG_ARM_COPROC_START == 0)
> >> +               return set_core_reg(vcpu, reg);
> >
> > ...but if we do go this path, you can't use coprocessor 0
> > to mean core register -- cp0 could be a valid coprocessor
> > (the ARM ARM reserves cp0..cp7 for "vendor specific features").
> > Use something outside 0..15.
>
> OK, changed that too (16).
>
>

And tomorrow they will add 16.

Have the first byte say where the state belongs (core or coprocessor)
second byte refer to the register family (if applicable), the rest
identifies the register within that family.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.