From: Peter Dinda <pdinda@northwestern.edu>
Date: Thu, 31 Jul 2008 19:25:44 +0000 (+0000)
Subject: write_cr3 optimization to reuse page table if cr3 is unchanged is now
X-Git-Tag: vmmhack1-ramdisk-boot-iso-puppy~29
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=commitdiff_plain;h=9b78fe7d41b07fd135eae2282cc18ccb964e7de3

write_cr3 optimization to reuse page table if cr3 is unchanged is now
set by flag at top of file, and flag is off

- optimization fails on linux (unclear why)
---

diff --git a/palacios/src/palacios/vmm_ctrl_regs.c b/palacios/src/palacios/vmm_ctrl_regs.c
index 4439355..6473e4a 100644
--- a/palacios/src/palacios/vmm_ctrl_regs.c
+++ b/palacios/src/palacios/vmm_ctrl_regs.c
@@ -20,6 +20,13 @@
 #endif
 
 
+// Set to 1 if CR3 reload with same value shall not
+// force a shadow page table flush
+// It makes windows loading MUCH faster. 
+// Note that this optimization appears to fail with a 2.6 linux kernel
+#define CR3_RELOAD_OPTIMIZATION 0
+
+
 
 
 
@@ -238,7 +245,7 @@ int handle_cr3_write(struct guest_info * info) {
       PrintDebug("Old Shadow CR3=%x; Old Guest CR3=%x\n", 
 		 *(uint_t*)shadow_cr3, *(uint_t*)guest_cr3);
       
-      if (1 || !CR3_32_SAME_BASE(new_cr3, guest_cr3)) { 
+      if (!CR3_RELOAD_OPTIMIZATION || !CR3_32_SAME_BASE(new_cr3, guest_cr3)) { 
 	addr_t shadow_pt;