diff --git a/sys/dev/acpica/acpi.c b/sys/dev/acpica/acpi.c
index 22d2b10ff905..0f4c48b3bb2f 100644
--- a/sys/dev/acpica/acpi.c
+++ b/sys/dev/acpica/acpi.c
@@ -1502,14 +1502,6 @@ acpi_set_resource(device_t dev, device_t child, int type, int rid,
     if (type == SYS_RES_IRQ)
 	return (0);
 
-    /*
-     * Don't reserve resources for CPU devices.  Some of these
-     * resources need to be allocated as shareable, but reservations
-     * are always non-shareable.
-     */
-    if (device_get_devclass(child) == devclass_find("cpu"))
-	return (0);
-
     /*
      * Reserve the resource.
      *
@@ -1703,7 +1695,7 @@ int
 acpi_bus_alloc_gas(device_t dev, int *type, int *rid, ACPI_GENERIC_ADDRESS *gas,
     struct resource **res, u_int flags)
 {
-    int error, res_type;
+    int error, old, res_type;
 
     error = ENOMEM;
     if (type == NULL || rid == NULL || gas == NULL || res == NULL)
@@ -1732,6 +1724,10 @@ acpi_bus_alloc_gas(device_t dev, int *type, int *rid, ACPI_GENERIC_ADDRESS *gas,
     if (gas->Address == 0 || gas->BitWidth == 0)
 	return (EINVAL);
 
+    /* Temporarily disable reserving resources in acpi_set_resource. */
+    old = sc->acpi_resources_reserved;
+    sc->acpi_resources_reserved = 0;
+
     bus_set_resource(dev, res_type, *rid, gas->Address,
 	gas->BitWidth / 8);
     *res = bus_alloc_resource_any(dev, res_type, rid, RF_ACTIVE | flags);
@@ -1741,6 +1737,8 @@ acpi_bus_alloc_gas(device_t dev, int *type, int *rid, ACPI_GENERIC_ADDRESS *gas,
     } else
 	bus_delete_resource(dev, res_type, *rid);
 
+    sc->acpi_resources_reserved = old;
+
     return (error);
 }
 
diff --git a/sys/dev/acpica/acpi_apei.c b/sys/dev/acpica/acpi_apei.c
index 6a3d9d10edd4..9cfd46c97430 100644
--- a/sys/dev/acpica/acpi_apei.c
+++ b/sys/dev/acpica/acpi_apei.c
@@ -711,7 +711,7 @@ apei_attach(device_t dev)
 		if (ge->v1.Header.Type == ACPI_HEST_TYPE_GENERIC_ERROR_V2) {
 			ge->res2_rid = rid++;
 			acpi_bus_alloc_gas(dev, &ge->res2_type, &ge->res2_rid,
-			    &ge->v2.ReadAckRegister, &ge->res2, 0);
+			    &ge->v2.ReadAckRegister, &ge->res2, RF_SHAREABLE);
 			if (ge->res2 == NULL)
 				device_printf(dev, "Can't allocate ack resource.\n");
 		}