[PATCH v2] ARM/KVM: save and restore generic timer registers
Marc Zyngier
marc.zyngier at arm.com
Thu Jun 20 14:39:59 EDT 2013
On 20/06/13 19:32, Christoffer Dall wrote:
>> So there is just one thing we absolutely need to make sure here: no vcpu
>> can run before they've all had their timer restored, and hence a stable
>> cntvoff. Otherwise two vcpus will have a different view of time.
>>
>> Can we guarantee this?
>>
>
> Do we need to? User space is free to modify time and all sort of other
> registers at any point during VM execution - it will just break the
> guest that it's running.
>
> I think the key here is that we expect the VM to be stopped for all
> save/restore operations (we can enforce it if we want to, which I am
> going to for the VGIC state, because we don't want to interfere with
> consistent state being written to the hardware).
If that's what we expect, then it's fine by me.
M.
--
Jazz is not dead. It just smells funny...
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