Check to see if we've reached the end of the map before attempting to

skip past an empty region, otherwise we end up generating an infinitely
long e820 map.  (Yes, there *are* real systems that provide e820 maps
with a zero-length region at the end...)

diff --git a/src/arch/i386/firmware/pcbios/e820mangler.S b/src/arch/i386/firmware/pcbios/e820mangler.S
index 89030a4..21d1bb9 100644 (file)
--- a/src/arch/i386/firmware/pcbios/e820mangler.S
+++ b/src/arch/i386/firmware/pcbios/e820mangler.S
@@ -361,7 +361,12 @@ int15_e820:
        pushl   %edx    
        call    split_e820
        pushfw
+       /* Skip empty region checking if we've reached the end of the
+        * map or hit an error, to avoid a potential endless loop.
+        */
        jc      1f
+       testl   %ebx, %ebx
+       jz      1f
        /* Check for an empty region */
        pushl   %eax
        movl    %es:8(%di), %eax