multiboot: fix e801 memory map

The e801 memory sizes in the multiboot structures hard-code the available low memory to 640. However, the value should not include the size of the EBDA. Fill the value in the option ROM, getting the size of low memory from the BIOS. Cc: Alexander Graf <agraf@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
qemu · Nov 30, 2012 · c6e052f · c6e052f
1 parent fe512d6
commit c6e052f
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diff --git a/pc-bios/multiboot.bin b/pc-bios/multiboot.bin
diff --git a/pc-bios/optionrom/multiboot.S b/pc-bios/optionrom/multiboot.S
@@ -75,6 +75,13 @@ run_multiboot:
 	shr		$4, %eax
 	mov		%ax, %fs
 
+	/* Account for the EBDA in the multiboot structure's e801
+	 * map.
+	 */
+	int		$0x12
+	cwtl
+	movl		%eax, %fs:4
+
 	/* ES = mmap_addr */
 	mov 		%fs:48, %eax
 	shr		$4, %eax