KVM: x86: Add debug register saving and restoring

Make use of the new KVM_GET/SET_DEBUGREGS to save/restore the x86 debug
registers.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/kvm.h b/kvm.h
index ae87d85..70bfbf8 100644
--- a/kvm.h
+++ b/kvm.h
@@ -40,6 +40,7 @@
 int kvm_has_sync_mmu(void);
 int kvm_has_vcpu_events(void);
 int kvm_has_robust_singlestep(void);
+int kvm_has_debugregs(void);
 
 #ifdef NEED_CPU_H
 int kvm_init_vcpu(CPUState *env);