lguest: move last_pages to lg_cpu

in our new model, pages are assigned to a virtual cpu, not to a guest.
We move it to the lg_cpu structure.
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/lguest/lg.h

@@ -57,6 +57,8 @@ struct lg_cpu {
 	unsigned long regs_page;
 	struct lguest_regs *regs;
 
+	struct lguest_pages *last_pages;
+
 	int cpu_pgd; /* which pgd this cpu is currently using */
 
 	/* If a hypercall was asked for, this points to the arguments. */
@@ -92,7 +94,6 @@ struct lguest
 
 	/* Bitmap of what has changed: see CHANGED_* above. */
 	int changed;
-	struct lguest_pages *last_pages;
 
 	struct pgdir pgdirs[4];
 

drivers/lguest/lguest_user.c

@@ -131,6 +131,10 @@ static int lg_cpu_start(struct lg_cpu *cpu, unsigned id, unsigned long start_ip)
 	 * reference, it is destroyed before close() is called. */
 	cpu->mm = get_task_mm(cpu->tsk);
 
+	/* We remember which CPU's pages this Guest used last, for optimization
+	 * when the same Guest runs on the same CPU twice. */
+	cpu->last_pages = NULL;
+
 	return 0;
 }
 
@@ -192,10 +196,6 @@ static int initialize(struct file *file, const unsigned long __user *input)
 	if (err)
 		goto free_regs;
 
-	/* We remember which CPU's pages this Guest used last, for optimization
-	 * when the same Guest runs on the same CPU twice. */
-	lg->last_pages = NULL;
-
 	/* We keep our "struct lguest" in the file's private_data. */
 	file->private_data = lg;
 

drivers/lguest/x86/core.c

@@ -80,9 +80,9 @@ static void copy_in_guest_info(struct lg_cpu *cpu, struct lguest_pages *pages)
 	 * same Guest we ran last time (and that Guest hasn't run anywhere else
 	 * meanwhile).  If that's not the case, we pretend everything in the
 	 * Guest has changed. */
-	if (__get_cpu_var(last_cpu) != cpu || lg->last_pages != pages) {
+	if (__get_cpu_var(last_cpu) != cpu || cpu->last_pages != pages) {
 		__get_cpu_var(last_cpu) = cpu;
-		lg->last_pages = pages;
+		cpu->last_pages = pages;
 		lg->changed = CHANGED_ALL;
 	}