diff --git a/lib/x86/fwcfg.c b/lib/x86/fwcfg.c
index 06ef62c..c2aaf5a 100644
--- a/lib/x86/fwcfg.c
+++ b/lib/x86/fwcfg.c
@@ -28,6 +28,10 @@
 	if ((str = getenv("TEST_DEVICE")))
 		no_test_device = !atol(str);
 
+	if ((str = getenv("MEMLIMIT")))
+		fw_override[FW_CFG_MAX_RAM] = atol(str) * 1024 * 1024;
+
+
     fw_override_done = true;
 }
 
diff --git a/lib/x86/fwcfg.h b/lib/x86/fwcfg.h
index 2f17461..64d4c6e 100644
--- a/lib/x86/fwcfg.h
+++ b/lib/x86/fwcfg.h
@@ -21,6 +21,7 @@
 #define FW_CFG_BOOT_MENU        0x0e
 #define FW_CFG_MAX_CPUS         0x0f
 #define FW_CFG_MAX_ENTRY        0x10
+#define FW_CFG_MAX_RAM		0x11
 
 #define FW_CFG_WRITE_CHANNEL    0x4000
 #define FW_CFG_ARCH_LOCAL       0x8000
diff --git a/lib/x86/setup.c b/lib/x86/setup.c
index b5941cd..7befe09 100644
--- a/lib/x86/setup.c
+++ b/lib/x86/setup.c
@@ -66,6 +66,9 @@
 	u64 upper_end = bootinfo->mem_upper * 1024ull;
 	u64 best_start = (uintptr_t) &edata;
 	u64 best_end = upper_end;
+	u64 max_end = fwcfg_get_u64(FW_CFG_MAX_RAM);
+	if (max_end == 0)
+		max_end = -1ull;
 	bool found = false;
 
 	uintptr_t mmap = bootinfo->mmap_addr;
@@ -79,8 +82,12 @@
 			continue;
 		if (mem->length < best_end - best_start)
 			continue;
+		if (mem->base_addr >= max_end)
+			continue;
 		best_start = mem->base_addr;
 		best_end = mem->base_addr + mem->length;
+		if (best_end > max_end)
+			best_end = max_end;
 		found = true;
 	}