diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index ba15dc9f11..21daf18c6b 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -4946,6 +4946,7 @@ qemuBuildMemoryDimmBackendStr(virDomainMemoryDefPtr mem,
 
 char *
 qemuBuildMemoryDeviceStr(virDomainMemoryDefPtr mem,
+                         virDomainDefPtr def,
                          virQEMUCapsPtr qemuCaps)
 {
     virBuffer buf = VIR_BUFFER_INITIALIZER;
@@ -4972,6 +4973,14 @@ qemuBuildMemoryDeviceStr(virDomainMemoryDefPtr mem,
             return NULL;
         }
 
+        if (mem->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_DIMM &&
+            mem->info.addr.dimm.slot >= def->mem.memory_slots) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("memory device slot '%u' exceeds slots count '%u'"),
+                           mem->info.addr.dimm.slot, def->mem.memory_slots);
+            return NULL;
+        }
+
         virBufferAsprintf(&buf, "pc-dimm,node=%d,memdev=mem%s,id=%s",
                           mem->targetNode, mem->info.alias, mem->info.alias);
 
@@ -8821,7 +8830,7 @@ qemuBuildCommandLine(virConnectPtr conn,
                                                           qemuCaps, cfg)))
                 goto error;
 
-            if (!(dimmStr = qemuBuildMemoryDeviceStr(def->mems[i], qemuCaps))) {
+            if (!(dimmStr = qemuBuildMemoryDeviceStr(def->mems[i], def, qemuCaps))) {
                 VIR_FREE(backStr);
                 goto error;
             }
diff --git a/src/qemu/qemu_command.h b/src/qemu/qemu_command.h
index a29db41d1e..675eb62401 100644
--- a/src/qemu/qemu_command.h
+++ b/src/qemu/qemu_command.h
@@ -175,6 +175,7 @@ int qemuBuildMemoryBackendStr(unsigned long long size,
                               bool force);
 
 char *qemuBuildMemoryDeviceStr(virDomainMemoryDefPtr mem,
+                               virDomainDefPtr def,
                                virQEMUCapsPtr qemuCaps);
 
 /* Legacy, pre device support */
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 58224bfc49..ba92320512 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -1736,7 +1736,7 @@ qemuDomainAttachMemory(virQEMUDriverPtr driver,
     if (virAsprintf(&objalias, "mem%s", mem->info.alias) < 0)
         goto cleanup;
 
-    if (!(devstr = qemuBuildMemoryDeviceStr(mem, priv->qemuCaps)))
+    if (!(devstr = qemuBuildMemoryDeviceStr(mem, vm->def, priv->qemuCaps)))
         goto cleanup;
 
     qemuDomainMemoryDeviceAlignSize(mem);