Commit 
0945d4b228 tried to fix the get_msr path for the
HV_X64_MSR_APIC_ASSIST_PAGE msr, but was poorly tested.  We should be
returning 0 if the read succeeded, and passing the value back to the
caller via the pdata out argument, not returning the value directly.
Signed-off-by: Mike Waychison <mikew@google.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
        case HV_X64_MSR_TPR:
                return kvm_hv_vapic_msr_read(vcpu, APIC_TASKPRI, pdata);
        case HV_X64_MSR_APIC_ASSIST_PAGE:
-               return vcpu->arch.hv_vapic;
+               data = vcpu->arch.hv_vapic;
+               break;
        default:
                pr_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr);
                return 1;