lguest: don't share Switcher PTE pages between guests.

We currently use the whole top PGD entry for the switcher, so we
simply share a fixed page of PTEs between all guests (actually, it's
one per Host CPU, to ensure isolation between guests).

Changes to a scheme where every guest has its own mappings.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/lguest/core.c

@@ -333,15 +333,10 @@ static int __init init(void)
 	if (err)
 		goto out;
 
-	/* Now we set up the pagetable implementation for the Guests. */
-	err = init_pagetables(lg_switcher_pages);
-	if (err)
-		goto unmap;
-
 	/* We might need to reserve an interrupt vector. */
 	err = init_interrupts();
 	if (err)
-		goto free_pgtables;
+		goto unmap;
 
 	/* /dev/lguest needs to be registered. */
 	err = lguest_device_init();
@@ -356,8 +351,6 @@ static int __init init(void)
 
 free_interrupts:
 	free_interrupts();
-free_pgtables:
-	free_pagetables();
 unmap:
 	unmap_switcher();
 out:
@@ -369,7 +362,6 @@ static void __exit fini(void)
 {
 	lguest_device_remove();
 	free_interrupts();
-	free_pagetables();
 	unmap_switcher();
 
 	lguest_arch_host_fini();

drivers/lguest/lg.h

@@ -14,9 +14,6 @@
 
 #include <asm/lguest.h>
 
-void free_pagetables(void);
-int init_pagetables(struct page **switcher_pages);
-
 struct pgdir {
 	unsigned long gpgdir;
 	pgd_t *pgdir;