lguest: per-vcpu lguest pgdir management

this patch makes the pgdir management per-vcpu. The pgdirs pool
is still guest-wide (although it'll probably need to grow when we
are really executing more vcpus), but the pgdidx index is gone,
since it makes no sense anymore. Instead, we use a per-vcpu
index.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c
index be8f046..0471018 100644
--- a/drivers/lguest/hypercalls.c
+++ b/drivers/lguest/hypercalls.c
@@ -62,7 +62,7 @@
 		if (args->arg1)
 			guest_pagetable_clear_all(cpu);
 		else
-			guest_pagetable_flush_user(lg);
+			guest_pagetable_flush_user(cpu);
 		break;
 
 	/* All these calls simply pass the arguments through to the right