From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoffer Dall <christoffer.dall@linaro.org>
Subject: Re: [PATCH v4 3/7] KVM: arm/arm64: Fix the documentation
Date: Thu, 8 Oct 2015 10:24:25 +0200
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Cc: 'Marc Zyngier' <marc.zyngier@arm.com>, kvmarm@lists.cs.columbia.edu,
 kvm@vger.kernel.org, 'Andre Przywara' <andre.przywara@arm.com>
To: Pavel Fedin <p.fedin@samsung.com>
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On Thu, Oct 08, 2015 at 09:52:02AM +0300, Pavel Fedin wrote:
>  Hello!
> 
> > > --- a/Documentation/virtual/kvm/devices/arm-vgic.txt
> > > +++ b/Documentation/virtual/kvm/devices/arm-vgic.txt
> > > @@ -44,28 +44,29 @@ Groups:
> > >    Attributes:
> > >      The attr field of kvm_device_attr encodes two values:
> > >      bits:     | 63   ....  40 | 39 ..  32  |  31   ....    0 |
> > > -    values:   |    reserved   |   cpu id   |      offset     |
> > > +    values:   |    reserved   |  cpu idx   |      offset     |
> > 
> > why should this be changed to cpu idx?
> 
>  Because it's index (from 0 to N - 1), and "cpu id" may confuse readers that it should be MPIDR
> affinity value. In register access function we do "vcpu = kvm_get_vcpu(dev->kvm, cpuid);" (see here:
> http://lxr.free-electrons.com/source/virt/kvm/arm/vgic-v2-emul.c#L664), and kvm_get_vcpu just
> indexes the array: http://lxr.free-electrons.com/source/include/linux/kvm_host.h#L427
>  I decided to change this after http://www.spinics.net/lists/kvm-arm/msg16359.html, Andre clearly
> mistook this ID for being affinity value.
>  Before GICv3 nobody saw the difference because we had only up to 16 CPUs, with IDs from 0 to 15, i.
> e. corresponding to indexes.
> 
ok, fair enough.  This kind of rationale is helpful to put in the commit
text though.

-Christoffer