Re: [PATCH] x86: convert x86_platform_ops to timespec64

From: Paolo Bonzini
Date: Mon Oct 16 2017 - 08:21:38 EST


On 16/10/2017 14:16, Arnd Bergmann wrote:
> On Mon, Oct 16, 2017 at 2:08 PM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>> On 16/10/2017 10:11, Arnd Bergmann wrote:
>>> Thanks!
>>>
>>> Since you've looked at it overall, do you have an opinion on the question
>>> how to fix the PV interface to deal with the pvclock_wall_clock overflow?
>>
>> It has to be done separately for each hypervisor.
>>
>> In KVM, for example, it is probably best to abandon
>> pvclock_read_wallclock altogether, and instead use the recently
>> introduced KVM_HC_CLOCK_PAIRING hypercall. drivers/ptp/ptp_kvm.c is
>> already using it and it's y2106 safe.
>
> Right, makes sense. I see that this interface is currently implemented
> only for 64-bit x86 in kvm_emulate_hypercall(). Could this be extended
> to x86-32 and the non-x86 architectures as well?

Yes, it could be implemented for x86-32 too. The whole pvclock concept
however is specific to x86.

Paolo