在 2016/10/24 23:18, Paolo Bonzini 写道:

On 24/10/2016 17:14, Radim Krčmář wrote:

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2016-10-24 16:39+0200, Paolo Bonzini:

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On 19/10/2016 19:24, Radim Krčmář wrote:

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+	if (vcpu->arch.st.msr_val & KVM_MSR_ENABLED)
+		if (kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
+					&vcpu->arch.st.steal,
+					sizeof(struct kvm_steal_time)) == 0) {
+			vcpu->arch.st.steal.preempted = 1;
+			kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
+					&vcpu->arch.st.steal,
+					sizeof(struct kvm_steal_time));
+		}

Please name this block of code.  Something like
  kvm_steal_time_set_preempted(vcpu);

While at it:

1) the kvm_read_guest_cached is not necessary.  You can rig the call to
kvm_write_guest_cached so that it only writes vcpu->arch.st.steal.preempted.

I agree.  kvm_write_guest_cached() always writes from offset 0, so we'd
want a new function that allows to specify a starting offset.

Yeah, let's leave it for a follow-up then!

I think I can make a having-offset version. :)

Thanks,

Paolo

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Using cached vcpu->arch.st.steal to avoid the read wouldn't be as good.