2017-11-13 9:37 GMT+08:00 Wanpeng Li <kernellwp@xxxxxxxxx>: > 2017-11-13 9:03 GMT+08:00 Wanpeng Li <kernellwp@xxxxxxxxx>: >> 2017-11-13 8:55 GMT+08:00 Liran Alon <LIRAN.ALON@xxxxxxxxxx>: >>> >>> >>> On 13/11/17 02:52, Wanpeng Li wrote: >>>> >>>> 2017-11-13 8:44 GMT+08:00 Liran Alon <LIRAN.ALON@xxxxxxxxxx>: >>>>> >>>>> >>>>> >>>>> On 13/11/17 02:40, Wanpeng Li wrote: >>>>>> >>>>>> >>>>>> 2017-11-05 22:11 GMT+08:00 Liran Alon <liran.alon@xxxxxxxxxx>: >>>>>>> >>>>>>> >>>>>>> When guest passes KVM it's pvclock-page GPA via WRMSR to >>>>>>> MSR_KVM_SYSTEM_TIME / MSR_KVM_SYSTEM_TIME_NEW, KVM don't initialize >>>>>>> pvclock-page to some start-values. It just requests a clock-update >>>>>>> which >>>>>> >>>>>> >>>>>> >>>>>> KVM does, please refer to memset(hv_clock, 0, size) in kvmclock_init(). >>>>> >>>>> >>>>> >>>>> kvmclock_init() is the code that runs in KVM-guest. I was talking here >>>>> about >>>>> the code that handles the WRMSR in KVM hypervisor code. >>>>> >>>>> The issue happens when the guest doesn't init pvclock-page as done in >>>>> kvmclock_init(). Not all guests behave nicely :) >>>> >>>> >>>> But the codes which you modify just works for kvm guest I think. >>> >>> No, it's the code that runs in KVM hypervisor for any guest that knows how >>> to work with KVM pv-clock PV interface. >>> Linux guest is just one of the possible guests which can use this interface. >>> kvmclock_init() you mentioned is part of the linux-guest. But there are >>> other guests which use KVM pv-clock PV interface. >> >> Good to know it, could you point one? > > In addition, there is a BUG_ON(if version != 0) just before the codes Oh, not mean version != 0, but I think we can move '& operation' to the setup. > which you added. I will move these avoid random junk logics into msr > setup in order that it can avoid '& operation' each time update the pv > stuff. I will send a patch later. > > Regards, > Wanpeng Li
