ch8: fix: domain cannot write to xenstore.

The access mode of xenstore should be changed before running domain.
We can pause domain when creating and then unpause it after we change
the access mode.

chapter8/Makefile

@@ -31,4 +31,8 @@ clean:
 	rm -f testkernel
 
 run: testkernel
-	sudo xm create -c domain_config
+	@sudo xm create -p domain_config
+	@sudo ./chmod_xenstore.sh
+	@sudo xm unpause Simplest_Kernel
+	@echo "Unpaused domain\n\n"
+	@sudo xm console Simplest_Kernel

chapter8/chmod_xenstore.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+dom_id=`xm domid Simplest_Kernel`
+echo "Making /local/domain/$dom_id writable..."
+sudo xenstore-chmod "/local/domain/$dom_id" b
+