Re: [kvm-devel] [PATCH 2/3] kvmclock - the host part.

Glauber de Oliveira Costa
2007-11-13T12:17:57Z

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Dong, Eddie escreveu:
>> +static void kvm_write_guest_time(struct kvm_vcpu *vcpu) +{
>> + struct timespec ts;
>> + int r;
>> +
>> + if (!vcpu->clock_gpa)
>> + return;
>> +
>> + /* Updates version to the next odd number, indicating
>> we're writing */
>> + vcpu->hv_clock.version++;
>> + kvm_write_guest(vcpu->kvm, vcpu->clock_gpa,
>> &vcpu->hv_clock, PAGE_SIZE);
>> +
>> + kvm_get_msr(vcpu, MSR_IA32_TIME_STAMP_COUNTER,
>> + &vcpu->hv_clock.last_tsc);
>> +
>> + ktime_get_ts(&ts);
>
> Do we need to disable preemption here?
After thinking for a little while, you are theoretically right.
In the current state, we could even be preempted between all operations
;-) Maybe after avi's suggestion of moving the call to it it will end up
in a preempt safe region, but anyway, it's safer to add the preempt
markers here.
I'll put it in next version, thanks

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