3 files changed, 25 insertions, 17 deletions
diff --git a/i386/i386at/biosmem.c b/i386/i386at/biosmem.c
index 9f86b66a..4f0914ca 100644
--- a/i386/i386at/biosmem.c
+++ b/i386/i386at/biosmem.c
@@ -995,3 +995,21 @@ biosmem_free_usable(void)
         biosmem_free_usable_entry(start, end);
     }
 }
+
+boolean_t
+biosmem_addr_available(phys_addr_t addr)
+{
+    struct biosmem_map_entry *entry;
+    unsigned i;
+
+    if (addr < BIOSMEM_BASE)
+        return FALSE;
+
+    for (i = 0; i < biosmem_map_size; i++) {
+        entry = &biosmem_map[i];
+
+        if (addr >= entry->base_addr && addr < entry->base_addr + entry->length)
+            return entry->type == BIOSMEM_TYPE_AVAILABLE;
+    }
+    return FALSE;
+}
diff --git a/i386/i386at/biosmem.h b/i386/i386at/biosmem.h
index 7824c168..76ab23a0 100644
--- a/i386/i386at/biosmem.h
+++ b/i386/i386at/biosmem.h
@@ -100,4 +100,10 @@ void biosmem_setup(void);
  */
 void biosmem_free_usable(void);
 
+/*
+ * Tell whether this address is marked as available in the biosmem and thus used
+ * for usable memory.
+ */
+boolean_t biosmem_addr_available(phys_addr_t addr);
+
 #endif /* _X86_BIOSMEM_H */
diff --git a/i386/i386at/mem.c b/i386/i386at/mem.c
index 61143185..e42e995d 100644
--- a/i386/i386at/mem.c
+++ b/i386/i386at/mem.c
@@ -36,24 +36,8 @@ dev_t		dev;
 vm_offset_t	off;
 vm_prot_t	prot;
 {
-	struct vm_page *p;
-
-	if (off == 0)
-		return 0;
-
-	/*
-	 * The legacy device mappings are included in the page tables and
-	 * need their own test.
-	 */
-	if (off >= 0xa0000 && off < 0x100000)
-		goto out;
-
-	p = vm_page_lookup_pa(off);
-
-	if (p != NULL) {
+	if (biosmem_addr_available(off))
 		return -1;
-	}
 
-out:
 	return i386_btop(off);
 }