[PATCH 09/12] xen: ask the hypervisor how much space it needs reserved

[Jeremy Fitzhardinge <jeremy@goop.org>]

[-- Attachment #1: xen-dynamic-topaddr.patch --]
[-- Type: text/plain, Size: 1149 bytes --]

Ask the hypervisor how much space it needs reserved, since 32-on-64
doesn't need any space, and it may change in future.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>

---
 arch/x86/xen/enlighten.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

===================================================================
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1085,6 +1085,17 @@ static const struct machine_ops __initda
 };
 
 
+static void __init xen_reserve_top(void)
+{
+	unsigned long top = HYPERVISOR_VIRT_START;
+	struct xen_platform_parameters pp;
+
+	if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
+		top = pp.virt_start;
+
+	reserve_top_address(-top + 2 * PAGE_SIZE);
+}
+
 /* First C function to be called on Xen boot */
 asmlinkage void __init xen_start_kernel(void)
 {
@@ -1134,7 +1145,7 @@ asmlinkage void __init xen_start_kernel(
 		paravirt_ops.kernel_rpl = 0;
 
 	/* set the limit of our address space */
-	reserve_top_address(-HYPERVISOR_VIRT_START + 2 * PAGE_SIZE);
+	xen_reserve_top();
 
 	/* set up basic CPUID stuff */
 	cpu_detect(&new_cpu_data);

--