1 file changed, 13 insertions(+)
arch/i386/kernel/setup.c | 13 +++++++++++++
This is necessary to allow dynamically loaded hypervisor modules, which
might not happen until userspace is already running, and also provides a
useful tool to benchmark the performance impact of reduced lowmem address
space.
Signed-off-by: Zachary Amsden <zach at vmware.com>
===================================================================
diff -r b6c100bb5ca5 -r 0adfc39039c7 arch/i386/kernel/setup.c
--- a/arch/i386/kernel/setup.c Tue Aug 01 01:32:00 2006 -0700
+++ b/arch/i386/kernel/setup.c Tue Aug 01 01:32:00 2006 -0700
@@ -917,6 +917,19 @@ static void __init parse_cmdline_early (
else if (!memcmp(from, "vmalloc=", 8))
__VMALLOC_RESERVE = memparse(from+8, &from);
+ /*
+ * reservedtop=size reserves a hole at the top of the kernel
+ * address space which a hypervisor can load into later.
+ * Needed for dynamically loaded hypervisors, so relocating
+ * the fixmap can be done before paging initialization.
+ * This hole must be a multiple of 4M.
+ */
+ else if (!memcmp(from, "reservedtop=", 12)) {
+ unsigned long reserved = memparse(from+12, &from);
+ reserved &= ~0x3fffff;
+ set_fixaddr_top(-reserved);
+ }
+
next_char:
c = *(from++);
if (!c)
