diff --git a/include/exec/memory.h b/include/exec/memory.h
index 15ade91..e45ce60 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -767,6 +767,8 @@
     bool is_iommu;
     RAMBlock *ram_block;
     Object *owner;
+    /* owner as TYPE_DEVICE. Used for re-entrancy checks in MR access hotpath */
+    DeviceState *dev;
 
     const MemoryRegionOps *ops;
     void *opaque;
@@ -791,6 +793,9 @@
     unsigned ioeventfd_nb;
     MemoryRegionIoeventfd *ioeventfds;
     RamDiscardManager *rdm; /* Only for RAM */
+
+    /* For devices designed to perform re-entrant IO into their own IO MRs */
+    bool disable_reentrancy_guard;
 };
 
 struct IOMMUMemoryRegion {
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index bd50ad5..7623703 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -162,6 +162,10 @@
     QLIST_ENTRY(NamedClockList) node;
 };
 
+typedef struct {
+    bool engaged_in_io;
+} MemReentrancyGuard;
+
 /**
  * DeviceState:
  * @realized: Indicates whether the device has been fully constructed.
@@ -194,6 +198,9 @@
     int alias_required_for_version;
     ResettableState reset;
     GSList *unplug_blockers;
+
+    /* Is the device currently in mmio/pio/dma? Used to prevent re-entrancy */
+    MemReentrancyGuard mem_reentrancy_guard;
 };
 
 struct DeviceListener {
diff --git a/softmmu/memory.c b/softmmu/memory.c
index b1a6cae..b7b3386 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -542,6 +542,18 @@
         access_size_max = 4;
     }
 
+    /* Do not allow more than one simultaneous access to a device's IO Regions */
+    if (mr->dev && !mr->disable_reentrancy_guard &&
+        !mr->ram_device && !mr->ram && !mr->rom_device && !mr->readonly) {
+        if (mr->dev->mem_reentrancy_guard.engaged_in_io) {
+            warn_report_once("Blocked re-entrant IO on MemoryRegion: "
+                             "%s at addr: 0x%" HWADDR_PRIX,
+                             memory_region_name(mr), addr);
+            return MEMTX_ACCESS_ERROR;
+        }
+        mr->dev->mem_reentrancy_guard.engaged_in_io = true;
+    }
+
     /* FIXME: support unaligned access? */
     access_size = MAX(MIN(size, access_size_max), access_size_min);
     access_mask = MAKE_64BIT_MASK(0, access_size * 8);
@@ -556,6 +568,9 @@
                         access_mask, attrs);
         }
     }
+    if (mr->dev) {
+        mr->dev->mem_reentrancy_guard.engaged_in_io = false;
+    }
     return r;
 }
 
@@ -1170,6 +1185,7 @@
     }
     mr->name = g_strdup(name);
     mr->owner = owner;
+    mr->dev = (DeviceState *) object_dynamic_cast(mr->owner, TYPE_DEVICE);
     mr->ram_block = NULL;
 
     if (name) {