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KVM: Hyper-V: do not do hypercall userspace exits if SynIC is disabled 

If SynIC is disabled, there is nothing that userspace can do to
handle these exits; on the other hand, userspace probably will
not know about KVM_EXIT_HYPERV_HCALL and complain about it or
even exit.  Just prevent anything bad from happening by handling
the hypercall in KVM and returning an "invalid hypercall" code.

Fixes: 83326e43f2
Cc: Andrey Smetanin <irqlevel@gmail.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hifive-unleashed-5.1
Paolo Bonzini 2016-03-29 11:23:25 +02:00
parent 321c5658c5
commit a2b5c3c0c8
1 changed files with 5 additions and 0 deletions
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5
arch/x86/kvm/hyperv.c
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@ -1116,6 +1116,11 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
break;
case HVCALL_POST_MESSAGE:
case HVCALL_SIGNAL_EVENT:
/* don't bother userspace if it has no way to handle it */
if (!vcpu_to_synic(vcpu)->active) {
res = HV_STATUS_INVALID_HYPERCALL_CODE;
break;
}
vcpu->run->exit_reason = KVM_EXIT_HYPERV;
vcpu->run->hyperv.type = KVM_EXIT_HYPERV_HCALL;
vcpu->run->hyperv.u.hcall.input = param;