kvm: API to obtain max supported mem slots

Introduce kvm_get_max_memslots() API that can be used to obtain the
maximum number of memslots supported by KVM.
Signed-off-by: NBharata B Rao <bharata@linux.vnet.ibm.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>

include/sysemu/kvm.h

@@ -527,4 +527,5 @@ int kvm_set_one_reg(CPUState *cs, uint64_t id, void *source);
  * Returns: 0 on success, or a negative errno on failure.
  */
 int kvm_get_one_reg(CPUState *cs, uint64_t id, void *target);
+int kvm_get_max_memslots(void);
 #endif

kvm-all.c

@@ -126,6 +126,13 @@ static const KVMCapabilityInfo kvm_required_capabilites[] = {
     KVM_CAP_LAST_INFO
 };
 
+int kvm_get_max_memslots(void)
+{
+    KVMState *s = KVM_STATE(current_machine->accelerator);
+
+    return s->nr_slots;
+}
+
 static KVMSlot *kvm_get_free_slot(KVMMemoryListener *kml)
 {
     KVMState *s = kvm_state;