diff --git a/hw/pci-host/astro.c b/hw/pci-host/astro.c
index 62e9c8acbf..039cc3ad01 100644
--- a/hw/pci-host/astro.c
+++ b/hw/pci-host/astro.c
@@ -521,6 +521,53 @@ static ElroyState *elroy_init(int num)
  * Astro Runway chip.
  */
 
+static void adjust_LMMIO_DIRECT_mapping(AstroState *s, unsigned int reg_index)
+{
+    MemoryRegion *lmmio_alias;
+    unsigned int lmmio_index, map_route;
+    hwaddr map_addr;
+    uint32_t map_size;
+    struct ElroyState *elroy;
+
+    /* pointer to LMMIO_DIRECT entry */
+    lmmio_index = reg_index / 3;
+    lmmio_alias = &s->lmmio_direct[lmmio_index];
+
+    map_addr  = s->ioc_ranges[3 * lmmio_index + 0];
+    map_size  = s->ioc_ranges[3 * lmmio_index + 1];
+    map_route = s->ioc_ranges[3 * lmmio_index + 2];
+
+    /* find elroy to which this address is routed */
+    map_route &= (ELROY_NUM - 1);
+    elroy = s->elroy[map_route];
+
+    if (lmmio_alias->enabled) {
+        memory_region_set_enabled(lmmio_alias, false);
+    }
+
+    map_addr = F_EXTEND(map_addr);
+    map_addr &= TARGET_PAGE_MASK;
+    map_size = (~map_size) + 1;
+    map_size &= TARGET_PAGE_MASK;
+
+    /* exit if disabled or zero map size */
+    if (!(map_addr & 1) || !map_size) {
+        return;
+    }
+
+    if (!memory_region_size(lmmio_alias)) {
+        memory_region_init_alias(lmmio_alias, OBJECT(elroy),
+                        "pci-lmmmio-alias", &elroy->pci_mmio,
+                        (uint32_t) map_addr, map_size);
+        memory_region_add_subregion(get_system_memory(), map_addr,
+                                 lmmio_alias);
+    } else {
+        memory_region_set_alias_offset(lmmio_alias, map_addr);
+        memory_region_set_size(lmmio_alias, map_size);
+        memory_region_set_enabled(lmmio_alias, true);
+    }
+}
+
 static MemTxResult astro_chip_read_with_attrs(void *opaque, hwaddr addr,
                                              uint64_t *data, unsigned size,
                                              MemTxAttrs attrs)
@@ -628,6 +675,11 @@ static MemTxResult astro_chip_write_with_attrs(void *opaque, hwaddr addr,
         break;
     case 0x0300 ... 0x03d8 - 1: /* LMMIO_DIRECT0_BASE... */
         put_val_in_arrary(s->ioc_ranges, 0x300, addr, size, val);
+        unsigned int index = (addr - 0x300) / 8;
+        /* check if one of the 4 LMMIO_DIRECT regs, each using 3 entries. */
+        if (index < LMMIO_DIRECT_RANGES * 3) {
+            adjust_LMMIO_DIRECT_mapping(s, index);
+        }
         break;
     case 0x10200:
     case 0x10220:
diff --git a/include/hw/pci-host/astro.h b/include/hw/pci-host/astro.h
index e2966917cd..832125a05a 100644
--- a/include/hw/pci-host/astro.h
+++ b/include/hw/pci-host/astro.h
@@ -24,6 +24,8 @@ OBJECT_DECLARE_SIMPLE_TYPE(ElroyState, ELROY_PCI_HOST_BRIDGE)
 #define LMMIO_DIST_BASE_ADDR      0xf4000000ULL
 #define LMMIO_DIST_BASE_SIZE       0x4000000ULL
 
+#define LMMIO_DIRECT_RANGES     4
+
 #define IOS_DIST_BASE_ADDR      0xfffee00000ULL
 #define IOS_DIST_BASE_SIZE           0x10000ULL
 
@@ -83,9 +85,7 @@ struct AstroState {
     struct ElroyState *elroy[ELROY_NUM];
 
     MemoryRegion this_mem;
-
-    MemoryRegion pci_mmio;
-    MemoryRegion pci_io;
+    MemoryRegion lmmio_direct[LMMIO_DIRECT_RANGES];
 
     IOMMUMemoryRegion iommu;
     AddressSpace iommu_as;