sel4vm, guest_ram: add 32-bit check

64-bit x86 VMs can have RAM in 64-bit memory, which cannot be used to store the kernel and initrd images, as those must be in 32-bit memory. This commit adds a check when 64-bit guests are enabled to ensure the returned region is in 32-bit space. Signed-off-by: Chris Guikema <[email protected]>
seL4 · Oct 25, 2023 · de8c0ab · de8c0ab
1 parent eb42051
commit de8c0ab
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/libsel4vm/src/guest_ram.c b/libsel4vm/src/guest_ram.c
@@ -185,7 +185,11 @@ int vm_ram_find_largest_free_region(vm_t *vm, uintptr_t *addr, size_t *size)
     /* find the largest unallocated region */
     for (int i = 0; i < guest_memory->num_ram_regions; i++) {
         if (!guest_memory->ram_regions[i].allocated &&
-            guest_memory->ram_regions[i].size > largest_size) {
+            guest_memory->ram_regions[i].size > largest_size
+#ifdef CONFIG_X86_64_VTX_64BIT_GUESTS
+            && guest_memory->ram_regions[i].start < UINT32_MAX
+#endif
+           ) {
             largest = i;
             largest_size = guest_memory->ram_regions[i].size;
         }