3 files changed, 14 insertions, 10 deletions

diff --git a/arch/x86/include/asm/lguest.h b/arch/x86/include/asm/lguest.h
index 0d97deba1e35..85ecdb80d121 100644
--- a/arch/x86/include/asm/lguest.h
+++ b/arch/x86/include/asm/lguest.h
@@ -23,6 +23,8 @@
 #else
 #define SWITCHER_ADDR 0xFFC00000
 #endif
+/* Where we map the Switcher, in both Host and Guest. */
+extern unsigned long switcher_addr;
 
 /* Found in switcher.S */
 extern unsigned long default_idt_entries[];
diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
index a5ebc0083d87..099252301132 100644
--- a/drivers/lguest/core.c
+++ b/drivers/lguest/core.c
@@ -20,7 +20,7 @@
 #include <asm/asm-offsets.h>
 #include "lg.h"
 
-
+unsigned long switcher_addr;
 static struct vm_struct *switcher_vma;
 static struct page **switcher_page;
 
@@ -75,25 +75,27 @@ static __init int map_switcher(void)
                 }
         }
 
+        switcher_addr = SWITCHER_ADDR;
+
         /*
          * First we check that the Switcher won't overlap the fixmap area at
          * the top of memory.  It's currently nowhere near, but it could have
          * very strange effects if it ever happened.
          */
-        if (SWITCHER_ADDR + (TOTAL_SWITCHER_PAGES+1)*PAGE_SIZE > FIXADDR_START){
+        if (switcher_addr + (TOTAL_SWITCHER_PAGES+1)*PAGE_SIZE > FIXADDR_START){
                 err = -ENOMEM;
                 printk("lguest: mapping switcher would thwack fixmap\n");
                 goto free_pages;
         }
 
         /*
-         * Now we reserve the "virtual memory area" we want: 0xFFC00000
-         * (SWITCHER_ADDR).  We might not get it in theory, but in practice
-         * it's worked so far.  The end address needs +1 because __get_vm_area
-         * allocates an extra guard page, so we need space for that.
+         * Now we reserve the "virtual memory area" we want.  We might
+         * not get it in theory, but in practice it's worked so far.
+         * The end address needs +1 because __get_vm_area allocates an
+         * extra guard page, so we need space for that.
          */
         switcher_vma = __get_vm_area(TOTAL_SWITCHER_PAGES * PAGE_SIZE,
-                                     VM_ALLOC, SWITCHER_ADDR, SWITCHER_ADDR
+                                     VM_ALLOC, switcher_addr, switcher_addr
                                      + (TOTAL_SWITCHER_PAGES+1) * PAGE_SIZE);
         if (!switcher_vma) {
                 err = -ENOMEM;
@@ -103,7 +105,7 @@ static __init int map_switcher(void)
 
         /*
          * This code actually sets up the pages we've allocated to appear at
-         * SWITCHER_ADDR.  map_vm_area() takes the vma we allocated above, the
+         * switcher_addr.  map_vm_area() takes the vma we allocated above, the
          * kind of pages we're mapping (kernel pages), and a pointer to our
          * array of struct pages.  It increments that pointer, but we don't
          * care.
diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index 4af12e1844d5..20fae765d600 100644
--- a/drivers/lguest/x86/core.c
+++ b/drivers/lguest/x86/core.c
@@ -59,14 +59,14 @@ static struct {
 /* Offset from where switcher.S was compiled to where we've copied it */
 static unsigned long switcher_offset(void)
 {
-        return SWITCHER_ADDR - (unsigned long)start_switcher_text;
+        return switcher_addr - (unsigned long)start_switcher_text;
 }
 
 /* This cpu's struct lguest_pages. */
 static struct lguest_pages *lguest_pages(unsigned int cpu)
 {
         return &(((struct lguest_pages *)
-                  (SWITCHER_ADDR + SHARED_SWITCHER_PAGES*PAGE_SIZE))[cpu]);
+                  (switcher_addr + SHARED_SWITCHER_PAGES*PAGE_SIZE))[cpu]);
 }
 
 static DEFINE_PER_CPU(struct lg_cpu *, lg_last_cpu);