Add a perf counter for write emulation caused by CR0.wp=0 emulation

Signed-off-by Kevin Tian <kevin.tian@intel.com>
diff -r d55e9ed3e5e2 xen/arch/x86/mm/shadow/multi.c
--- a/xen/arch/x86/mm/shadow/multi.c	Fri Jan 04 13:42:13 2008 +0800
+++ b/xen/arch/x86/mm/shadow/multi.c	Tue Jan 08 10:26:38 2008 +0800
@@ -2935,7 +2935,10 @@ static int sh_page_fault(struct vcpu *v,
     if ( is_hvm_domain(d) 
          && unlikely(!hvm_wp_enabled(v)) 
          && regs->error_code == (PFEC_write_access|PFEC_page_present) )
+    {
+        perfc_incr(shadow_fault_emulate_wp);
         goto emulate;
+    }
 
     perfc_incr(shadow_fault_fixed);
     d->arch.paging.log_dirty.fault_count++;
diff -r d55e9ed3e5e2 xen/include/asm-x86/perfc_defn.h
--- a/xen/include/asm-x86/perfc_defn.h	Fri Jan 04 13:42:13 2008 +0800
+++ b/xen/include/asm-x86/perfc_defn.h	Tue Jan 08 10:21:22 2008 +0800
@@ -56,6 +56,7 @@ PERFCOUNTER(shadow_fault_emulate_write, 
 PERFCOUNTER(shadow_fault_emulate_write, "shadow_fault emulates a write")
 PERFCOUNTER(shadow_fault_emulate_failed, "shadow_fault emulator fails")
 PERFCOUNTER(shadow_fault_emulate_stack, "shadow_fault emulate stack write")
+PERFCOUNTER(shadow_fault_emulate_wp, "shadow_fault emulate for CR0.WP=0")
 PERFCOUNTER(shadow_fault_early_jmp_emul, "jmp to shadow emulate early")
 PERFCOUNTER(shadow_fault_early_emul_fail, "jmp to shadow emulate early failed")
 PERFCOUNTER(shadow_fault_mmio,     "shadow_fault handled as mmio")