Re: [PATCH 27/27] KVM: PPC: Add Documentation about PV interface

Alexander Graf
2010-07-04T09:04:11Z

On 04.07.2010, at 00:41, Benjamin Herrenschmidt wrote:

> On Fri, 2010-07-02 at 18:27 +0200, Segher Boessenkool wrote:
>>> +To find out if we're running on KVM or not, we overlay the PVR
>>> register. Usually
>>> +the PVR register contains an id that identifies your CPU type. If,
>>> however, you
>>> +pass KVM_PVR_PARA in the register that you want the PVR result in,
>>> the register
>>> +still contains KVM_PVR_PARA after the mfpvr call.
>>> +
>>> + LOAD_REG_IMM(r5, KVM_PVR_PARA)
>>> + mfpvr r5
>>> + [r5 still contains KVM_PVR_PARA]
>>
>> I love this part :-)
>
> Me not :-)
>
> It should be in the device-tree instead, or something like that. Enough
> games with PVR...

My biggest concern about putting things in the device-tree is that I was trying to keep things as separate as possible. Why does the firmware have to know that it's running in KVM? Why do I have to patch 3 projects (Linux, OpenBIOS, Qemu) when I could go with patching a single one (Linux)?

Alex