[RFC PATCH 01/10] KVM: PPC: BOOK3S: PR: Fix PURR and SPURR emulation

Alexander Graf agraf at suse.de
Fri Jan 31 21:47:44 EST 2014

On 31.01.2014, at 11:38, Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com> wrote:

> Alexander Graf <agraf at suse.de> writes:
>> On 01/28/2014 05:44 PM, Aneesh Kumar K.V wrote:
>>> We definitely don't need to emulate mtspr, because both the registers
>>> are hypervisor resource.
>> This patch description doesn't cover what the patch actually does. It 
>> changes the implementation from "always tell the guest it uses 100%" to 
>> "give the guest an accurate amount of cpu time spent inside guest
>> context".
> Will fix that
>> Also, I think we either go with full hyp semantics which means we also 
>> emulate the offset or we go with no hyp awareness in the guest at all 
>> which means we also don't emulate SPURR which is a hyp privileged
>> register.
> Can you clarify this ?

In the 2.06 ISA SPURR is hypervisor privileged. That changed for 2.07 where it became supervisor privileged. So I suppose your patch is ok. When reviewing those patches I only had 2.06 around because power.org was broken.


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