From: Jack Lange <jarusl@cs.northwestern.edu>
Date: Tue, 3 Feb 2009 20:13:04 +0000 (-0600)
Subject: modified the shadow paging files to separate them based on CPU mode
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=commitdiff_plain;h=53f181096ad02cde9f79e30e2238ddad43ede574;p=palacios.releases.git

modified the shadow paging files to separate them based on CPU mode
---

diff --git a/palacios/include/palacios/vmm_shadow_paging.h b/palacios/include/palacios/vmm_shadow_paging.h
index bea54aa..1b63e8b 100644
--- a/palacios/include/palacios/vmm_shadow_paging.h
+++ b/palacios/include/palacios/vmm_shadow_paging.h
@@ -35,14 +35,6 @@ struct shadow_page_state {
   v3_reg_t guest_cr0;
 
 
-
-
-  // Page table struct lookup table
-  struct hashtable * pt_cache;
-
-  // Guest CR3 to Shadow CR3 Lookup Table
-  struct hashtable *  cr3_cache;
-
   /* SOON TO BE DEPRECATED */
   // Hash table that contains a mapping of guest pte addresses to host pte addresses
   struct hashtable *  cached_ptes;
diff --git a/palacios/src/palacios/vmm_shadow_paging.c b/palacios/src/palacios/vmm_shadow_paging.c
index 55920ed..6a0b3be 100644
--- a/palacios/src/palacios/vmm_shadow_paging.c
+++ b/palacios/src/palacios/vmm_shadow_paging.c
@@ -81,38 +81,23 @@ static int pte_equals(addr_t key1, addr_t key2) {
   return (key1 == key2);
 }
 
-static uint_t cr3_hash_fn(addr_t key) {
-  return hash_long(key, 32);
-}
-
-static int cr3_equals(addr_t key1, addr_t key2) {
-  return (key1 == key2);
-}
-
-
+static addr_t create_new_shadow_pt();
+static void inject_guest_pf(struct guest_info * info, addr_t fault_addr, pf_error_t error_code);
+static int is_guest_pf(pt_access_status_t guest_access, pt_access_status_t shadow_access);
 
-static int activate_shadow_pt_32(struct guest_info * info);
-static int activate_shadow_pt_32pae(struct guest_info * info);
-static int activate_shadow_pt_64(struct guest_info * info);
 
+#include "vmm_shadow_paging_32.h"
+#include "vmm_shadow_paging_32pae.h"
+#include "vmm_shadow_paging_64.h"
 
-static int handle_shadow_pagefault_32(struct guest_info * info, addr_t fault_addr, pf_error_t error_code);
-static int handle_shadow_pagefault_32pae(struct guest_info * info, addr_t fault_addr, pf_error_t error_code);
-static int handle_shadow_pagefault_64(struct guest_info * info, addr_t fault_addr, pf_error_t error_code);
 
 
-static int cache_page_tables_32(struct guest_info * info, addr_t pde);
-static int cache_page_tables_64(struct guest_info * info, addr_t pde);
-
 int v3_init_shadow_page_state(struct guest_info * info) {
   struct shadow_page_state * state = &(info->shdw_pg_state);
   
   state->guest_cr3 = 0;
   state->guest_cr0 = 0;
 
-  state->cr3_cache = create_hashtable(0, &cr3_hash_fn, &cr3_equals);
-
-  state->cached_cr3 = 0;
   state->cached_ptes = NULL;
 
   return 0;
@@ -122,178 +107,6 @@ int v3_init_shadow_page_state(struct guest_info * info) {
 
 
 
-int v3_cache_page_tables(struct guest_info * info, addr_t cr3) {
-  switch(v3_get_cpu_mode(info)) {
-  case PROTECTED:
-    return cache_page_tables_32(info, CR3_TO_PDE32_PA(cr3));
-  default:
-    return -1;
-  }
-}
-
-static int cache_page_tables_32(struct guest_info * info, addr_t pde) {
-  struct shadow_page_state * state = &(info->shdw_pg_state);
-  addr_t pde_host_addr;
-  pde32_t * tmp_pde;
-  struct hashtable * pte_cache = NULL;
-  int i = 0;
-
-  if (pde == state->cached_cr3) {
-    return 1;
-  }
-
-  if (state->cached_ptes != NULL) {
-    hashtable_destroy(state->cached_ptes, 0, 0);
-    state->cached_ptes = NULL;
-  }
-
-  state->cached_cr3 = pde;
-
-  pte_cache = create_hashtable(0, &pte_hash_fn, &pte_equals);
-  state->cached_ptes = pte_cache;
-
-  if (guest_pa_to_host_va(info, pde, &pde_host_addr) == -1) {
-    PrintError("Could not lookup host address of guest PDE\n");
-    return -1;
-  }
-
-  tmp_pde = (pde32_t *)pde_host_addr;
-
-  add_pte_map(pte_cache, pde, pde_host_addr);
-
-
-  for (i = 0; i < MAX_PDE32_ENTRIES; i++) {
-    if ((tmp_pde[i].present) && (tmp_pde[i].large_page == 0)) {
-      addr_t pte_host_addr;
-
-      if (guest_pa_to_host_va(info, (addr_t)(BASE_TO_PAGE_ADDR(tmp_pde[i].pt_base_addr)), &pte_host_addr) == -1) {
-	PrintError("Could not lookup host address of guest PDE\n");
-	return -1;
-      }
-
-      add_pte_map(pte_cache, (addr_t)(BASE_TO_PAGE_ADDR(tmp_pde[i].pt_base_addr)), pte_host_addr); 
-    }
-  }
-
-  return 0;
-
-}
-
-
-static int cache_page_tables_64(struct guest_info * info, addr_t pde) {
-  return -1;
-}
-
-
-int v3_replace_shdw_page32(struct guest_info * info, addr_t location, pte32_t * new_page, pte32_t * old_page) {
-  pde32_t * shadow_pd = (pde32_t *)CR3_TO_PDE32_VA(info->ctrl_regs.cr3);
-  pde32_t * shadow_pde =  (pde32_t *)&(shadow_pd[PDE32_INDEX(location)]);
-
-  if (shadow_pde->large_page == 0) {
-    pte32_t * shadow_pt = (pte32_t *)(addr_t)BASE_TO_PAGE_ADDR(shadow_pde->pt_base_addr);
-    pte32_t * shadow_pte = (pte32_t *)&(shadow_pt[PTE32_INDEX(location)]);
-
-    //if (shadow_pte->present == 1) {
-    *(uint_t *)old_page = *(uint_t *)shadow_pte;
-    //}
-
-    *(uint_t *)shadow_pte = *(uint_t *)new_page;
-
-  } else {
-    // currently unhandled
-    PrintError("Replacing large shadow pages not implemented\n");
-    return -1;
-  }
-  
-  return 0;
-}
-
-
-
-
-
-// We assume that shdw_pg_state.guest_cr3 is pointing to the page tables we want to activate
-// We also assume that the CPU mode has not changed during this page table transition
-static int activate_shadow_pt_32(struct guest_info * info) {
-  struct cr3_32 * shadow_cr3 = (struct cr3_32 *)&(info->ctrl_regs.cr3);
-  struct cr3_32 * guest_cr3 = (struct cr3_32 *)&(info->shdw_pg_state.guest_cr3);
-  int cached = 0;
-  
-  // Check if shadow page tables are in the cache
-  cached = cache_page_tables_32(info, CR3_TO_PDE32_PA(*(addr_t *)guest_cr3));
-  
-  if (cached == -1) {
-    PrintError("CR3 Cache failed\n");
-    return -1;
-  } else if (cached == 0) {
-    addr_t shadow_pt;
-    
-    PrintDebug("New CR3 is different - flushing shadow page table %p\n", shadow_cr3 );
-    delete_page_tables_32(CR3_TO_PDE32_VA(*(uint_t*)shadow_cr3));
-    
-    shadow_pt = v3_create_new_shadow_pt();
-    
-    shadow_cr3->pdt_base_addr = (addr_t)V3_PAddr((void *)(addr_t)PAGE_BASE_ADDR(shadow_pt));
-    PrintDebug( "Created new shadow page table %p\n", (void *)(addr_t)shadow_cr3->pdt_base_addr );
-  } else {
-    PrintDebug("Reusing cached shadow Page table\n");
-  }
-  
-  shadow_cr3->pwt = guest_cr3->pwt;
-  shadow_cr3->pcd = guest_cr3->pcd;
-  
-  return 0;
-}
-
-static int activate_shadow_pt_32pae(struct guest_info * info) {
-  PrintError("Activating 32 bit PAE page tables not implemented\n");
-  return -1;
-}
-
-static int activate_shadow_pt_64_cb(page_type_t type, addr_t vaddr, addr_t page_ptr, addr_t page_pa, void * private_data) {
-  PrintDebug("CB: Page: %p->%p (host_ptr=%p), Type: %s\n", (void *)vaddr, (void *)page_pa, (void *)page_ptr, v3_page_type_to_str(type));
-  return 0;
-}
-
-
-static int activate_shadow_pt_64(struct guest_info * info) {
-  //  struct cr3_64 * shadow_cr3 = (struct cr3_64 *)&(info->ctrl_regs.cr3);
-  struct cr3_64 * guest_cr3 = (struct cr3_64 *)&(info->shdw_pg_state.guest_cr3);
-  int cached = 0;
-  
-  v3_walk_guest_pt_64(info, info->shdw_pg_state.guest_cr3, activate_shadow_pt_64_cb, NULL);
-
-  
-
-  return -1;
-
-
-  // Check if shadow page tables are in the cache
-  cached = cache_page_tables_64(info, CR3_TO_PDE32_PA(*(addr_t *)guest_cr3));
-	      /*  
-  if (cached == -1) {
-    PrintError("CR3 Cache failed\n");
-    return -1;
-  } else if (cached == 0) {
-    addr_t shadow_pt;
-    
-    PrintDebug("New CR3 is different - flushing shadow page table %p\n", shadow_cr3 );
-    delete_page_tables_32(CR3_TO_PDE32_VA(*(uint_t*)shadow_cr3));
-    
-    shadow_pt = v3_create_new_shadow_pt();
-    
-    shadow_cr3->pml4t_base_addr = (addr_t)V3_PAddr((void *)(addr_t)PAGE_BASE_ADDR(shadow_pt));
-    PrintDebug( "Created new shadow page table %p\n", (void *)(addr_t)shadow_cr3->pml4t_base_addr );
-  } else {
-    PrintDebug("Reusing cached shadow Page table\n");
-  }
-  
-  shadow_cr3->pwt = guest_cr3->pwt;
-  shadow_cr3->pcd = guest_cr3->pcd;
-  
-  return 0;
-		      */
-}
 
 
 // Reads the guest CR3 register
@@ -363,7 +176,9 @@ int v3_handle_shadow_pagefault(struct guest_info * info, addr_t fault_addr, pf_e
   }
 }
 
-addr_t v3_create_new_shadow_pt() {
+
+
+static addr_t create_new_shadow_pt() {
   void * host_pde = 0;
 
   host_pde = V3_VAddr(V3_AllocPages(1));
@@ -417,470 +232,8 @@ static int is_guest_pf(pt_access_status_t guest_access, pt_access_status_t shado
 
 
 
-/* 
- * *
- * * 
- * * 64 bit Page table fault handlers
- * *
- * *
- */
-
-static int handle_shadow_pagefault_64(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) {
-  pt_access_status_t guest_access;
-  pt_access_status_t shadow_access;
-  int ret; 
-  PrintDebug("64 bit shadow page fault\n");
-
-  ret = v3_check_guest_pt_32(info, info->shdw_pg_state.guest_cr3, fault_addr, error_code, &guest_access);
-
-  PrintDebug("Guest Access Check: %d (access=%d)\n", ret, guest_access);
-
-  ret = v3_check_host_pt_32(info->ctrl_regs.cr3, fault_addr, error_code, &shadow_access);
-
-  PrintDebug("Shadow Access Check: %d (access=%d)\n", ret, shadow_access);
-  
-
-  PrintError("64 bit shadow paging not implemented\n");
-  return -1;
-}
 
 
-/* 
- * *
- * * 
- * * 32 bit PAE  Page table fault handlers
- * *
- * *
- */
-
-static int handle_shadow_pagefault_32pae(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) {
-  PrintError("32 bit PAE shadow paging not implemented\n");
-  return -1;
-}
-
-
-
-
-
-
-
-/* 
- * *
- * * 
- * * 32 bit Page table fault handlers
- * *
- * *
- */
-static int handle_large_pagefault_32(struct guest_info * info, 
-				    addr_t fault_addr, pf_error_t error_code, 
-				     pte32_t * shadow_pt, pde32_4MB_t * large_guest_pde);
-
-static int handle_shadow_pte32_fault(struct guest_info * info, 
-				     addr_t fault_addr, 
-				     pf_error_t error_code,
-				     pte32_t * shadow_pt, 
-				     pte32_t * guest_pt);
-
-
-static int handle_shadow_pagefault_32(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) {
-  pde32_t * guest_pd = NULL;
-  pde32_t * shadow_pd = CR3_TO_PDE32_VA(info->ctrl_regs.cr3);
-  addr_t guest_cr3 = CR3_TO_PDE32_PA(info->shdw_pg_state.guest_cr3);
-  pt_access_status_t guest_pde_access;
-  pt_access_status_t shadow_pde_access;
-  pde32_t * guest_pde = NULL;
-  pde32_t * shadow_pde = (pde32_t *)&(shadow_pd[PDE32_INDEX(fault_addr)]);
-
-  PrintDebug("Shadow page fault handler: %p\n", (void*) fault_addr );
-
-  if (guest_pa_to_host_va(info, guest_cr3, (addr_t*)&guest_pd) == -1) {
-    PrintError("Invalid Guest PDE Address: 0x%p\n",  (void *)guest_cr3);
-    return -1;
-  } 
-
-  guest_pde = (pde32_t *)&(guest_pd[PDE32_INDEX(fault_addr)]);
-
-
-  // Check the guest page permissions
-  guest_pde_access = v3_can_access_pde32(guest_pd, fault_addr, error_code);
-
-  // Check the shadow page permissions
-  shadow_pde_access = v3_can_access_pde32(shadow_pd, fault_addr, error_code);
-  
-  /* Was the page fault caused by the Guest's page tables? */
-  if (is_guest_pf(guest_pde_access, shadow_pde_access) == 1) {
-    PrintDebug("Injecting PDE pf to guest: (guest access error=%d) (pf error code=%d)\n", 
-	       *(uint_t *)&guest_pde_access, *(uint_t *)&error_code);
-    inject_guest_pf(info, fault_addr, error_code);
-    return 0;
-  }
-
-  
-  if (shadow_pde_access == PT_ACCESS_NOT_PRESENT) 
-    {
-      pte32_t * shadow_pt =  (pte32_t *)v3_create_new_shadow_pt();
-
-      shadow_pde->present = 1;
-      shadow_pde->user_page = guest_pde->user_page;
-      //    shadow_pde->large_page = guest_pde->large_page;
-      shadow_pde->large_page = 0;
-      
-
-      // VMM Specific options
-      shadow_pde->write_through = 0;
-      shadow_pde->cache_disable = 0;
-      shadow_pde->global_page = 0;
-      //
-      
-      guest_pde->accessed = 1;
-      
-      shadow_pde->pt_base_addr = PAGE_BASE_ADDR((addr_t)V3_PAddr(shadow_pt));
-      
-      if (guest_pde->large_page == 0) {
-	pte32_t * guest_pt = NULL;
-	shadow_pde->writable = guest_pde->writable;
-
-	if (guest_pa_to_host_va(info, BASE_TO_PAGE_ADDR(guest_pde->pt_base_addr), (addr_t*)&guest_pt) == -1) {
-	  // Machine check the guest
-	  PrintDebug("Invalid Guest PTE Address: 0x%p\n", (void *)BASE_TO_PAGE_ADDR(guest_pde->pt_base_addr));
-	  v3_raise_exception(info, MC_EXCEPTION);
-	  return 0;
-	}
-
-	if (handle_shadow_pte32_fault(info, fault_addr, error_code, shadow_pt, guest_pt)  == -1) {
-	  PrintError("Error handling Page fault caused by PTE\n");
-	  return -1;
-	}
-      } else {
-	// ??  What if guest pde is dirty a this point?
-	((pde32_4MB_t *)guest_pde)->dirty = 0;
-	shadow_pde->writable = 0;
-      }
-    }
-  else if (shadow_pde_access == PT_ACCESS_OK) 
-    {
-      //
-      // PTE fault
-      //
-      pte32_t * shadow_pt = (pte32_t *)V3_VAddr( (void*)(addr_t) BASE_TO_PAGE_ADDR(shadow_pde->pt_base_addr) );
-
-      if (guest_pde->large_page == 0) {
-	pte32_t * guest_pt = NULL;
-
-	if (guest_pa_to_host_va(info, BASE_TO_PAGE_ADDR(guest_pde->pt_base_addr), (addr_t*)&guest_pt) == -1) {
-	  // Machine check the guest
-	  PrintDebug("Invalid Guest PTE Address: 0x%p\n", (void *)BASE_TO_PAGE_ADDR(guest_pde->pt_base_addr));
-	  v3_raise_exception(info, MC_EXCEPTION);
-	  return 0;
-	}
-	
-	if (handle_shadow_pte32_fault(info, fault_addr, error_code, shadow_pt, guest_pt)  == -1) {
-	  PrintError("Error handling Page fault caused by PTE\n");
-	  return -1;
-	}
-      } else if (guest_pde->large_page == 1) {
-	if (handle_large_pagefault_32(info, fault_addr, error_code, shadow_pt, (pde32_4MB_t *)guest_pde) == -1) {
-	  PrintError("Error handling large pagefault\n");
-	  return -1;
-	}
-      }
-    }
-  else if ((shadow_pde_access == PT_ACCESS_WRITE_ERROR) && 
-	   (guest_pde->large_page == 1) && 
-	   (((pde32_4MB_t *)guest_pde)->dirty == 0)) 
-    {
-      //
-      // Page Directory Entry marked read-only
-      // Its a large page and we need to update the dirty bit in the guest
-      //
-
-      PrintDebug("Large page write error... Setting dirty bit and returning\n");
-      ((pde32_4MB_t *)guest_pde)->dirty = 1;
-      shadow_pde->writable = guest_pde->writable;
-      return 0;
-      
-    } 
-  else if (shadow_pde_access == PT_ACCESS_USER_ERROR) 
-    {
-      //
-      // Page Directory Entry marked non-user
-      //      
-      PrintDebug("Shadow Paging User access error (shadow_pde_access=0x%x, guest_pde_access=0x%x)\n", 
-		 shadow_pde_access, guest_pde_access);
-      inject_guest_pf(info, fault_addr, error_code);
-      return 0;
-    }
-  else 
-    {
-      // inject page fault in guest
-      inject_guest_pf(info, fault_addr, error_code);
-      PrintDebug("Unknown Error occurred (shadow_pde_access=%d)\n", shadow_pde_access);
-      PrintDebug("Manual Says to inject page fault into guest\n");
-#ifdef DEBUG_SHADOW_PAGING
-      PrintDebug("Guest PDE: (access=%d)\n\t", guest_pde_access);
-      PrintPTEntry(PAGE_PD32, fault_addr, guest_pde);
-      PrintDebug("Shadow PDE: (access=%d)\n\t", shadow_pde_access);
-      PrintPTEntry(PAGE_PD32, fault_addr, shadow_pde);
-#endif
-
-      return 0; 
-    }
-
-  PrintDebug("Returning end of PDE function (rip=%p)\n", (void *)(addr_t)(info->rip));
-  return 0;
-}
-
-
-
-/* The guest status checks have already been done,
- * only special case shadow checks remain
- */
-static int handle_large_pagefault_32(struct guest_info * info, 
-				    addr_t fault_addr, pf_error_t error_code, 
-				    pte32_t * shadow_pt, pde32_4MB_t * large_guest_pde) 
-{
-  pt_access_status_t shadow_pte_access = v3_can_access_pte32(shadow_pt, fault_addr, error_code);
-  pte32_t * shadow_pte = (pte32_t *)&(shadow_pt[PTE32_INDEX(fault_addr)]);
-  addr_t guest_fault_pa = BASE_TO_PAGE_ADDR_4MB(large_guest_pde->page_base_addr) + PAGE_OFFSET_4MB(fault_addr);  
-
-  struct v3_shadow_region * shdw_reg = v3_get_shadow_region(info, guest_fault_pa);
-
- 
-  if ((shdw_reg == NULL) || 
-      (shdw_reg->host_type == SHDW_REGION_INVALID)) {
-    // Inject a machine check in the guest
-    PrintDebug("Invalid Guest Address in page table (0x%p)\n", (void *)guest_fault_pa);
-    v3_raise_exception(info, MC_EXCEPTION);
-    return -1;
-  }
-
-  if (shadow_pte_access == PT_ACCESS_OK) {
-    // Inconsistent state...
-    // Guest Re-Entry will flush tables and everything should now workd
-    PrintDebug("Inconsistent state... Guest re-entry should flush tlb\n");
-    return 0;
-  }
-
-  
-  if (shadow_pte_access == PT_ACCESS_NOT_PRESENT) {
-    // Get the guest physical address of the fault
-
-    if ((shdw_reg->host_type == SHDW_REGION_ALLOCATED) || 
-	(shdw_reg->host_type == SHDW_REGION_WRITE_HOOK)) {
-      struct shadow_page_state * state = &(info->shdw_pg_state);
-      addr_t shadow_pa = v3_get_shadow_addr(shdw_reg, guest_fault_pa);
-
-      shadow_pte->page_base_addr = PAGE_BASE_ADDR(shadow_pa);
-
-      shadow_pte->present = 1;
-
-      /* We are assuming that the PDE entry has precedence
-       * so the Shadow PDE will mirror the guest PDE settings, 
-       * and we don't have to worry about them here
-       * Allow everything
-       */
-      shadow_pte->user_page = 1;
-
-      if (find_pte_map(state->cached_ptes, PAGE_ADDR(guest_fault_pa)) != NULL) {
-	// Check if the entry is a page table...
-	PrintDebug("Marking page as Guest Page Table (large page)\n");
-	shadow_pte->vmm_info = PT32_GUEST_PT;
-	shadow_pte->writable = 0;
-      } else if (shdw_reg->host_type == SHDW_REGION_WRITE_HOOK) {
-	shadow_pte->writable = 0;
-      } else {
-	shadow_pte->writable = 1;
-      }
-
-      //set according to VMM policy
-      shadow_pte->write_through = 0;
-      shadow_pte->cache_disable = 0;
-      shadow_pte->global_page = 0;
-      //
-      
-    } else {
-      // Handle hooked pages as well as other special pages
-      //      if (handle_special_page_fault(info, fault_addr, guest_fault_pa, error_code) == -1) {
-
-      if (v3_handle_mem_full_hook(info, fault_addr, guest_fault_pa, shdw_reg, error_code) == -1) {
-	PrintError("Special Page Fault handler returned error for address: %p\n", (void *)fault_addr);
-	return -1;
-      }
-    }
-  } else if (shadow_pte_access == PT_ACCESS_WRITE_ERROR) {
-
-    if (shdw_reg->host_type == SHDW_REGION_WRITE_HOOK) {
-
-      if (v3_handle_mem_wr_hook(info, fault_addr, guest_fault_pa, shdw_reg, error_code) == -1) {
-	PrintError("Special Page Fault handler returned error for address: %p\n", (void *)fault_addr);
-	return -1;
-      }
-    } else if (shadow_pte->vmm_info == PT32_GUEST_PT) {
-      struct shadow_page_state * state = &(info->shdw_pg_state);
-      PrintDebug("Write operation on Guest PAge Table Page (large page)\n");
-      state->cached_cr3 = 0;
-      shadow_pte->writable = 1;
-    }
-
-  } else {
-    PrintError("Error in large page fault handler...\n");
-    PrintError("This case should have been handled at the top level handler\n");
-    return -1;
-  }
-
-  PrintDebug("Returning from large page fault handler\n");
-  return 0;
-}
-
-
-
-
-/* 
- * We assume the the guest pte pointer has already been translated to a host virtual address
- */
-static int handle_shadow_pte32_fault(struct guest_info * info, 
-				     addr_t fault_addr, 
-				     pf_error_t error_code,
-				     pte32_t * shadow_pt, 
-				     pte32_t * guest_pt) {
-
-  pt_access_status_t guest_pte_access;
-  pt_access_status_t shadow_pte_access;
-  pte32_t * guest_pte = (pte32_t *)&(guest_pt[PTE32_INDEX(fault_addr)]);;
-  pte32_t * shadow_pte = (pte32_t *)&(shadow_pt[PTE32_INDEX(fault_addr)]);
-  addr_t guest_pa = BASE_TO_PAGE_ADDR((addr_t)(guest_pte->page_base_addr)) +  PAGE_OFFSET(fault_addr);
-
-  struct v3_shadow_region * shdw_reg =  v3_get_shadow_region(info, guest_pa);
-
-  if ((shdw_reg == NULL) || 
-      (shdw_reg->host_type == SHDW_REGION_INVALID)) {
-    // Inject a machine check in the guest
-    PrintDebug("Invalid Guest Address in page table (0x%p)\n", (void *)guest_pa);
-    v3_raise_exception(info, MC_EXCEPTION);
-    return 0;
-  }
-
-  // Check the guest page permissions
-  guest_pte_access = v3_can_access_pte32(guest_pt, fault_addr, error_code);
-
-  // Check the shadow page permissions
-  shadow_pte_access = v3_can_access_pte32(shadow_pt, fault_addr, error_code);
-  
-#ifdef DEBUG_SHADOW_PAGING
-  PrintDebug("Guest PTE: (access=%d)\n\t", guest_pte_access);
-  PrintPTEntry(PAGE_PT32, fault_addr, guest_pte);
-  PrintDebug("Shadow PTE: (access=%d)\n\t", shadow_pte_access);
-  PrintPTEntry(PAGE_PT32, fault_addr, shadow_pte);
-#endif
-  
-  /* Was the page fault caused by the Guest's page tables? */
-  if (is_guest_pf(guest_pte_access, shadow_pte_access) == 1) {
-    PrintDebug("Access error injecting pf to guest (guest access error=%d) (pf error code=%d)\n", 
-	       guest_pte_access, *(uint_t*)&error_code);    
-    inject_guest_pf(info, fault_addr, error_code);
-    return 0; 
-  }
-  
-  
-  if (shadow_pte_access == PT_ACCESS_OK) {
-    // Inconsistent state...
-    // Guest Re-Entry will flush page tables and everything should now work
-    PrintDebug("Inconsistent state... Guest re-entry should flush tlb\n");
-    return 0;
-  }
-
-
-  if (shadow_pte_access == PT_ACCESS_NOT_PRESENT) {
-    // Page Table Entry Not Present
-    PrintDebug("guest_pa =%p\n", (void *)guest_pa);
-
-    if ((shdw_reg->host_type == SHDW_REGION_ALLOCATED) ||
-	(shdw_reg->host_type == SHDW_REGION_WRITE_HOOK)) {
-      struct shadow_page_state * state = &(info->shdw_pg_state);
-      addr_t shadow_pa = v3_get_shadow_addr(shdw_reg, guest_pa);
-      
-      shadow_pte->page_base_addr = PAGE_BASE_ADDR(shadow_pa);
-      
-      shadow_pte->present = guest_pte->present;
-      shadow_pte->user_page = guest_pte->user_page;
-      
-      //set according to VMM policy
-      shadow_pte->write_through = 0;
-      shadow_pte->cache_disable = 0;
-      shadow_pte->global_page = 0;
-      //
-      
-      guest_pte->accessed = 1;
-      
-      if (find_pte_map(state->cached_ptes, PAGE_ADDR(guest_pa)) != NULL) {
-	// Check if the entry is a page table...
-	PrintDebug("Marking page as Guest Page Table %d\n", shadow_pte->writable);
-	shadow_pte->vmm_info = PT32_GUEST_PT;
-      }
-
-      if (shdw_reg->host_type == SHDW_REGION_WRITE_HOOK) {
-	shadow_pte->writable = 0;
-      } else if (guest_pte->dirty == 1) {
-	shadow_pte->writable = guest_pte->writable;
-      } else if ((guest_pte->dirty == 0) && (error_code.write == 1)) {
-	shadow_pte->writable = guest_pte->writable;
-	guest_pte->dirty = 1;
-	
-	if (shadow_pte->vmm_info == PT32_GUEST_PT) {
-	  // Well that was quick...
-	  struct shadow_page_state * state = &(info->shdw_pg_state);
-	  PrintDebug("Immediate Write operation on Guest PAge Table Page\n");
-	  state->cached_cr3 = 0;
-	}
-
-      } else if ((guest_pte->dirty == 0) && (error_code.write == 0)) {  // was =
-	shadow_pte->writable = 0;
-      }
-
-    } else {
-      // Page fault handled by hook functions
-
-      if (v3_handle_mem_full_hook(info, fault_addr, guest_pa, shdw_reg, error_code) == -1) {
-	PrintError("Special Page fault handler returned error for address: %p\n",  (void *)fault_addr);
-	return -1;
-      }
-    }
-    /*
-  } else if ((shadow_pte_access == PT_ACCESS_WRITE_ERROR) &&
-	     (guest_pte->dirty == 0)) {
-    */
-  } else if (shadow_pte_access == PT_ACCESS_WRITE_ERROR) {
-    guest_pte->dirty = 1;
-
-    if (shdw_reg->host_type == SHDW_REGION_WRITE_HOOK) {
-      if (v3_handle_mem_wr_hook(info, fault_addr, guest_pa, shdw_reg, error_code) == -1) {
-	PrintError("Special Page fault handler returned error for address: %p\n",  (void *)fault_addr);
-	return -1;
-      }
-    } else {
-      PrintDebug("Shadow PTE Write Error\n");
-      shadow_pte->writable = guest_pte->writable;
-    }
-
-    if (shadow_pte->vmm_info == PT32_GUEST_PT) {
-      struct shadow_page_state * state = &(info->shdw_pg_state);
-      PrintDebug("Write operation on Guest PAge Table Page\n");
-      state->cached_cr3 = 0;
-    }
-
-    return 0;
-
-  } else {
-    // Inject page fault into the guest	
-    inject_guest_pf(info, fault_addr, error_code);
-    PrintError("PTE Page fault fell through... Not sure if this should ever happen\n");
-    PrintError("Manual Says to inject page fault into guest\n");
-    return -1;
-  }
-
-  PrintDebug("Returning end of function\n");
-  return 0;
-}
 
 
 
diff --git a/palacios/src/palacios/vmm_shadow_paging_32.h b/palacios/src/palacios/vmm_shadow_paging_32.h
new file mode 100644
index 0000000..7e0106a
--- /dev/null
+++ b/palacios/src/palacios/vmm_shadow_paging_32.h
@@ -0,0 +1,497 @@
+
+static int cache_page_tables_32(struct guest_info * info, addr_t pde) {
+  struct shadow_page_state * state = &(info->shdw_pg_state);
+  addr_t pde_host_addr;
+  pde32_t * tmp_pde;
+  struct hashtable * pte_cache = NULL;
+  int i = 0;
+
+  if (pde == state->cached_cr3) {
+    return 1;
+  }
+
+  if (state->cached_ptes != NULL) {
+    hashtable_destroy(state->cached_ptes, 0, 0);
+    state->cached_ptes = NULL;
+  }
+
+  state->cached_cr3 = pde;
+
+  pte_cache = create_hashtable(0, &pte_hash_fn, &pte_equals);
+  state->cached_ptes = pte_cache;
+
+  if (guest_pa_to_host_va(info, pde, &pde_host_addr) == -1) {
+    PrintError("Could not lookup host address of guest PDE\n");
+    return -1;
+  }
+
+  tmp_pde = (pde32_t *)pde_host_addr;
+
+  add_pte_map(pte_cache, pde, pde_host_addr);
+
+
+  for (i = 0; i < MAX_PDE32_ENTRIES; i++) {
+    if ((tmp_pde[i].present) && (tmp_pde[i].large_page == 0)) {
+      addr_t pte_host_addr;
+
+      if (guest_pa_to_host_va(info, (addr_t)(BASE_TO_PAGE_ADDR(tmp_pde[i].pt_base_addr)), &pte_host_addr) == -1) {
+	PrintError("Could not lookup host address of guest PDE\n");
+	return -1;
+      }
+
+      add_pte_map(pte_cache, (addr_t)(BASE_TO_PAGE_ADDR(tmp_pde[i].pt_base_addr)), pte_host_addr); 
+    }
+  }
+
+  return 0;
+
+}
+
+
+
+// We assume that shdw_pg_state.guest_cr3 is pointing to the page tables we want to activate
+// We also assume that the CPU mode has not changed during this page table transition
+static int activate_shadow_pt_32(struct guest_info * info) {
+  struct cr3_32 * shadow_cr3 = (struct cr3_32 *)&(info->ctrl_regs.cr3);
+  struct cr3_32 * guest_cr3 = (struct cr3_32 *)&(info->shdw_pg_state.guest_cr3);
+  int cached = 0;
+  
+  // Check if shadow page tables are in the cache
+  cached = cache_page_tables_32(info, CR3_TO_PDE32_PA(*(addr_t *)guest_cr3));
+  
+  if (cached == -1) {
+    PrintError("CR3 Cache failed\n");
+    return -1;
+  } else if (cached == 0) {
+    addr_t shadow_pt;
+    
+    PrintDebug("New CR3 is different - flushing shadow page table %p\n", shadow_cr3 );
+    delete_page_tables_32(CR3_TO_PDE32_VA(*(uint_t*)shadow_cr3));
+    
+    shadow_pt = create_new_shadow_pt();
+    
+    shadow_cr3->pdt_base_addr = (addr_t)V3_PAddr((void *)(addr_t)PAGE_BASE_ADDR(shadow_pt));
+    PrintDebug( "Created new shadow page table %p\n", (void *)(addr_t)shadow_cr3->pdt_base_addr );
+  } else {
+    PrintDebug("Reusing cached shadow Page table\n");
+  }
+  
+  shadow_cr3->pwt = guest_cr3->pwt;
+  shadow_cr3->pcd = guest_cr3->pcd;
+  
+  return 0;
+}
+
+/* 
+ * *
+ * * 
+ * * 32 bit Page table fault handlers
+ * *
+ * *
+ */
+static int handle_large_pagefault_32(struct guest_info * info, 
+				    addr_t fault_addr, pf_error_t error_code, 
+				     pte32_t * shadow_pt, pde32_4MB_t * large_guest_pde);
+
+static int handle_shadow_pte32_fault(struct guest_info * info, 
+				     addr_t fault_addr, 
+				     pf_error_t error_code,
+				     pte32_t * shadow_pt, 
+				     pte32_t * guest_pt);
+
+
+static int handle_shadow_pagefault_32(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) {
+  pde32_t * guest_pd = NULL;
+  pde32_t * shadow_pd = CR3_TO_PDE32_VA(info->ctrl_regs.cr3);
+  addr_t guest_cr3 = CR3_TO_PDE32_PA(info->shdw_pg_state.guest_cr3);
+  pt_access_status_t guest_pde_access;
+  pt_access_status_t shadow_pde_access;
+  pde32_t * guest_pde = NULL;
+  pde32_t * shadow_pde = (pde32_t *)&(shadow_pd[PDE32_INDEX(fault_addr)]);
+
+  PrintDebug("Shadow page fault handler: %p\n", (void*) fault_addr );
+
+  if (guest_pa_to_host_va(info, guest_cr3, (addr_t*)&guest_pd) == -1) {
+    PrintError("Invalid Guest PDE Address: 0x%p\n",  (void *)guest_cr3);
+    return -1;
+  } 
+
+  guest_pde = (pde32_t *)&(guest_pd[PDE32_INDEX(fault_addr)]);
+
+
+  // Check the guest page permissions
+  guest_pde_access = v3_can_access_pde32(guest_pd, fault_addr, error_code);
+
+  // Check the shadow page permissions
+  shadow_pde_access = v3_can_access_pde32(shadow_pd, fault_addr, error_code);
+  
+  /* Was the page fault caused by the Guest's page tables? */
+  if (is_guest_pf(guest_pde_access, shadow_pde_access) == 1) {
+    PrintDebug("Injecting PDE pf to guest: (guest access error=%d) (pf error code=%d)\n", 
+	       *(uint_t *)&guest_pde_access, *(uint_t *)&error_code);
+    inject_guest_pf(info, fault_addr, error_code);
+    return 0;
+  }
+
+  
+  if (shadow_pde_access == PT_ACCESS_NOT_PRESENT) 
+    {
+      pte32_t * shadow_pt =  (pte32_t *)create_new_shadow_pt();
+
+      shadow_pde->present = 1;
+      shadow_pde->user_page = guest_pde->user_page;
+      //    shadow_pde->large_page = guest_pde->large_page;
+      shadow_pde->large_page = 0;
+      
+
+      // VMM Specific options
+      shadow_pde->write_through = 0;
+      shadow_pde->cache_disable = 0;
+      shadow_pde->global_page = 0;
+      //
+      
+      guest_pde->accessed = 1;
+      
+      shadow_pde->pt_base_addr = PAGE_BASE_ADDR((addr_t)V3_PAddr(shadow_pt));
+      
+      if (guest_pde->large_page == 0) {
+	pte32_t * guest_pt = NULL;
+	shadow_pde->writable = guest_pde->writable;
+
+	if (guest_pa_to_host_va(info, BASE_TO_PAGE_ADDR(guest_pde->pt_base_addr), (addr_t*)&guest_pt) == -1) {
+	  // Machine check the guest
+	  PrintDebug("Invalid Guest PTE Address: 0x%p\n", (void *)BASE_TO_PAGE_ADDR(guest_pde->pt_base_addr));
+	  v3_raise_exception(info, MC_EXCEPTION);
+	  return 0;
+	}
+
+	if (handle_shadow_pte32_fault(info, fault_addr, error_code, shadow_pt, guest_pt)  == -1) {
+	  PrintError("Error handling Page fault caused by PTE\n");
+	  return -1;
+	}
+      } else {
+	// ??  What if guest pde is dirty a this point?
+	((pde32_4MB_t *)guest_pde)->dirty = 0;
+	shadow_pde->writable = 0;
+      }
+    }
+  else if (shadow_pde_access == PT_ACCESS_OK) 
+    {
+      //
+      // PTE fault
+      //
+      pte32_t * shadow_pt = (pte32_t *)V3_VAddr( (void*)(addr_t) BASE_TO_PAGE_ADDR(shadow_pde->pt_base_addr) );
+
+      if (guest_pde->large_page == 0) {
+	pte32_t * guest_pt = NULL;
+
+	if (guest_pa_to_host_va(info, BASE_TO_PAGE_ADDR(guest_pde->pt_base_addr), (addr_t*)&guest_pt) == -1) {
+	  // Machine check the guest
+	  PrintDebug("Invalid Guest PTE Address: 0x%p\n", (void *)BASE_TO_PAGE_ADDR(guest_pde->pt_base_addr));
+	  v3_raise_exception(info, MC_EXCEPTION);
+	  return 0;
+	}
+	
+	if (handle_shadow_pte32_fault(info, fault_addr, error_code, shadow_pt, guest_pt)  == -1) {
+	  PrintError("Error handling Page fault caused by PTE\n");
+	  return -1;
+	}
+      } else if (guest_pde->large_page == 1) {
+	if (handle_large_pagefault_32(info, fault_addr, error_code, shadow_pt, (pde32_4MB_t *)guest_pde) == -1) {
+	  PrintError("Error handling large pagefault\n");
+	  return -1;
+	}
+      }
+    }
+  else if ((shadow_pde_access == PT_ACCESS_WRITE_ERROR) && 
+	   (guest_pde->large_page == 1) && 
+	   (((pde32_4MB_t *)guest_pde)->dirty == 0)) 
+    {
+      //
+      // Page Directory Entry marked read-only
+      // Its a large page and we need to update the dirty bit in the guest
+      //
+
+      PrintDebug("Large page write error... Setting dirty bit and returning\n");
+      ((pde32_4MB_t *)guest_pde)->dirty = 1;
+      shadow_pde->writable = guest_pde->writable;
+      return 0;
+      
+    } 
+  else if (shadow_pde_access == PT_ACCESS_USER_ERROR) 
+    {
+      //
+      // Page Directory Entry marked non-user
+      //      
+      PrintDebug("Shadow Paging User access error (shadow_pde_access=0x%x, guest_pde_access=0x%x)\n", 
+		 shadow_pde_access, guest_pde_access);
+      inject_guest_pf(info, fault_addr, error_code);
+      return 0;
+    }
+  else 
+    {
+      // inject page fault in guest
+      inject_guest_pf(info, fault_addr, error_code);
+      PrintDebug("Unknown Error occurred (shadow_pde_access=%d)\n", shadow_pde_access);
+      PrintDebug("Manual Says to inject page fault into guest\n");
+#ifdef DEBUG_SHADOW_PAGING
+      PrintDebug("Guest PDE: (access=%d)\n\t", guest_pde_access);
+      PrintPTEntry(PAGE_PD32, fault_addr, guest_pde);
+      PrintDebug("Shadow PDE: (access=%d)\n\t", shadow_pde_access);
+      PrintPTEntry(PAGE_PD32, fault_addr, shadow_pde);
+#endif
+
+      return 0; 
+    }
+
+  PrintDebug("Returning end of PDE function (rip=%p)\n", (void *)(addr_t)(info->rip));
+  return 0;
+}
+
+
+
+/* The guest status checks have already been done,
+ * only special case shadow checks remain
+ */
+static int handle_large_pagefault_32(struct guest_info * info, 
+				    addr_t fault_addr, pf_error_t error_code, 
+				    pte32_t * shadow_pt, pde32_4MB_t * large_guest_pde) 
+{
+  pt_access_status_t shadow_pte_access = v3_can_access_pte32(shadow_pt, fault_addr, error_code);
+  pte32_t * shadow_pte = (pte32_t *)&(shadow_pt[PTE32_INDEX(fault_addr)]);
+  addr_t guest_fault_pa = BASE_TO_PAGE_ADDR_4MB(large_guest_pde->page_base_addr) + PAGE_OFFSET_4MB(fault_addr);  
+
+  struct v3_shadow_region * shdw_reg = v3_get_shadow_region(info, guest_fault_pa);
+
+ 
+  if ((shdw_reg == NULL) || 
+      (shdw_reg->host_type == SHDW_REGION_INVALID)) {
+    // Inject a machine check in the guest
+    PrintDebug("Invalid Guest Address in page table (0x%p)\n", (void *)guest_fault_pa);
+    v3_raise_exception(info, MC_EXCEPTION);
+    return -1;
+  }
+
+  if (shadow_pte_access == PT_ACCESS_OK) {
+    // Inconsistent state...
+    // Guest Re-Entry will flush tables and everything should now workd
+    PrintDebug("Inconsistent state... Guest re-entry should flush tlb\n");
+    return 0;
+  }
+
+  
+  if (shadow_pte_access == PT_ACCESS_NOT_PRESENT) {
+    // Get the guest physical address of the fault
+
+    if ((shdw_reg->host_type == SHDW_REGION_ALLOCATED) || 
+	(shdw_reg->host_type == SHDW_REGION_WRITE_HOOK)) {
+      struct shadow_page_state * state = &(info->shdw_pg_state);
+      addr_t shadow_pa = v3_get_shadow_addr(shdw_reg, guest_fault_pa);
+
+      shadow_pte->page_base_addr = PAGE_BASE_ADDR(shadow_pa);
+
+      shadow_pte->present = 1;
+
+      /* We are assuming that the PDE entry has precedence
+       * so the Shadow PDE will mirror the guest PDE settings, 
+       * and we don't have to worry about them here
+       * Allow everything
+       */
+      shadow_pte->user_page = 1;
+
+      if (find_pte_map(state->cached_ptes, PAGE_ADDR(guest_fault_pa)) != NULL) {
+	// Check if the entry is a page table...
+	PrintDebug("Marking page as Guest Page Table (large page)\n");
+	shadow_pte->vmm_info = PT32_GUEST_PT;
+	shadow_pte->writable = 0;
+      } else if (shdw_reg->host_type == SHDW_REGION_WRITE_HOOK) {
+	shadow_pte->writable = 0;
+      } else {
+	shadow_pte->writable = 1;
+      }
+
+      //set according to VMM policy
+      shadow_pte->write_through = 0;
+      shadow_pte->cache_disable = 0;
+      shadow_pte->global_page = 0;
+      //
+      
+    } else {
+      // Handle hooked pages as well as other special pages
+      //      if (handle_special_page_fault(info, fault_addr, guest_fault_pa, error_code) == -1) {
+
+      if (v3_handle_mem_full_hook(info, fault_addr, guest_fault_pa, shdw_reg, error_code) == -1) {
+	PrintError("Special Page Fault handler returned error for address: %p\n", (void *)fault_addr);
+	return -1;
+      }
+    }
+  } else if (shadow_pte_access == PT_ACCESS_WRITE_ERROR) {
+
+    if (shdw_reg->host_type == SHDW_REGION_WRITE_HOOK) {
+
+      if (v3_handle_mem_wr_hook(info, fault_addr, guest_fault_pa, shdw_reg, error_code) == -1) {
+	PrintError("Special Page Fault handler returned error for address: %p\n", (void *)fault_addr);
+	return -1;
+      }
+    } else if (shadow_pte->vmm_info == PT32_GUEST_PT) {
+      struct shadow_page_state * state = &(info->shdw_pg_state);
+      PrintDebug("Write operation on Guest PAge Table Page (large page)\n");
+      state->cached_cr3 = 0;
+      shadow_pte->writable = 1;
+    }
+
+  } else {
+    PrintError("Error in large page fault handler...\n");
+    PrintError("This case should have been handled at the top level handler\n");
+    return -1;
+  }
+
+  PrintDebug("Returning from large page fault handler\n");
+  return 0;
+}
+
+
+
+
+/* 
+ * We assume the the guest pte pointer has already been translated to a host virtual address
+ */
+static int handle_shadow_pte32_fault(struct guest_info * info, 
+				     addr_t fault_addr, 
+				     pf_error_t error_code,
+				     pte32_t * shadow_pt, 
+				     pte32_t * guest_pt) {
+
+  pt_access_status_t guest_pte_access;
+  pt_access_status_t shadow_pte_access;
+  pte32_t * guest_pte = (pte32_t *)&(guest_pt[PTE32_INDEX(fault_addr)]);;
+  pte32_t * shadow_pte = (pte32_t *)&(shadow_pt[PTE32_INDEX(fault_addr)]);
+  addr_t guest_pa = BASE_TO_PAGE_ADDR((addr_t)(guest_pte->page_base_addr)) +  PAGE_OFFSET(fault_addr);
+
+  struct v3_shadow_region * shdw_reg =  v3_get_shadow_region(info, guest_pa);
+
+  if ((shdw_reg == NULL) || 
+      (shdw_reg->host_type == SHDW_REGION_INVALID)) {
+    // Inject a machine check in the guest
+    PrintDebug("Invalid Guest Address in page table (0x%p)\n", (void *)guest_pa);
+    v3_raise_exception(info, MC_EXCEPTION);
+    return 0;
+  }
+
+  // Check the guest page permissions
+  guest_pte_access = v3_can_access_pte32(guest_pt, fault_addr, error_code);
+
+  // Check the shadow page permissions
+  shadow_pte_access = v3_can_access_pte32(shadow_pt, fault_addr, error_code);
+  
+#ifdef DEBUG_SHADOW_PAGING
+  PrintDebug("Guest PTE: (access=%d)\n\t", guest_pte_access);
+  PrintPTEntry(PAGE_PT32, fault_addr, guest_pte);
+  PrintDebug("Shadow PTE: (access=%d)\n\t", shadow_pte_access);
+  PrintPTEntry(PAGE_PT32, fault_addr, shadow_pte);
+#endif
+  
+  /* Was the page fault caused by the Guest's page tables? */
+  if (is_guest_pf(guest_pte_access, shadow_pte_access) == 1) {
+    PrintDebug("Access error injecting pf to guest (guest access error=%d) (pf error code=%d)\n", 
+	       guest_pte_access, *(uint_t*)&error_code);    
+    inject_guest_pf(info, fault_addr, error_code);
+    return 0; 
+  }
+  
+  
+  if (shadow_pte_access == PT_ACCESS_OK) {
+    // Inconsistent state...
+    // Guest Re-Entry will flush page tables and everything should now work
+    PrintDebug("Inconsistent state... Guest re-entry should flush tlb\n");
+    return 0;
+  }
+
+
+  if (shadow_pte_access == PT_ACCESS_NOT_PRESENT) {
+    // Page Table Entry Not Present
+    PrintDebug("guest_pa =%p\n", (void *)guest_pa);
+
+    if ((shdw_reg->host_type == SHDW_REGION_ALLOCATED) ||
+	(shdw_reg->host_type == SHDW_REGION_WRITE_HOOK)) {
+      struct shadow_page_state * state = &(info->shdw_pg_state);
+      addr_t shadow_pa = v3_get_shadow_addr(shdw_reg, guest_pa);
+      
+      shadow_pte->page_base_addr = PAGE_BASE_ADDR(shadow_pa);
+      
+      shadow_pte->present = guest_pte->present;
+      shadow_pte->user_page = guest_pte->user_page;
+      
+      //set according to VMM policy
+      shadow_pte->write_through = 0;
+      shadow_pte->cache_disable = 0;
+      shadow_pte->global_page = 0;
+      //
+      
+      guest_pte->accessed = 1;
+      
+      if (find_pte_map(state->cached_ptes, PAGE_ADDR(guest_pa)) != NULL) {
+	// Check if the entry is a page table...
+	PrintDebug("Marking page as Guest Page Table %d\n", shadow_pte->writable);
+	shadow_pte->vmm_info = PT32_GUEST_PT;
+      }
+
+      if (shdw_reg->host_type == SHDW_REGION_WRITE_HOOK) {
+	shadow_pte->writable = 0;
+      } else if (guest_pte->dirty == 1) {
+	shadow_pte->writable = guest_pte->writable;
+      } else if ((guest_pte->dirty == 0) && (error_code.write == 1)) {
+	shadow_pte->writable = guest_pte->writable;
+	guest_pte->dirty = 1;
+	
+	if (shadow_pte->vmm_info == PT32_GUEST_PT) {
+	  // Well that was quick...
+	  struct shadow_page_state * state = &(info->shdw_pg_state);
+	  PrintDebug("Immediate Write operation on Guest PAge Table Page\n");
+	  state->cached_cr3 = 0;
+	}
+
+      } else if ((guest_pte->dirty == 0) && (error_code.write == 0)) {  // was =
+	shadow_pte->writable = 0;
+      }
+
+    } else {
+      // Page fault handled by hook functions
+
+      if (v3_handle_mem_full_hook(info, fault_addr, guest_pa, shdw_reg, error_code) == -1) {
+	PrintError("Special Page fault handler returned error for address: %p\n",  (void *)fault_addr);
+	return -1;
+      }
+    }
+  } else if (shadow_pte_access == PT_ACCESS_WRITE_ERROR) {
+    guest_pte->dirty = 1;
+
+    if (shdw_reg->host_type == SHDW_REGION_WRITE_HOOK) {
+      if (v3_handle_mem_wr_hook(info, fault_addr, guest_pa, shdw_reg, error_code) == -1) {
+	PrintError("Special Page fault handler returned error for address: %p\n",  (void *)fault_addr);
+	return -1;
+      }
+    } else {
+      PrintDebug("Shadow PTE Write Error\n");
+      shadow_pte->writable = guest_pte->writable;
+    }
+
+    if (shadow_pte->vmm_info == PT32_GUEST_PT) {
+      struct shadow_page_state * state = &(info->shdw_pg_state);
+      PrintDebug("Write operation on Guest PAge Table Page\n");
+      state->cached_cr3 = 0;
+    }
+
+    return 0;
+
+  } else {
+    // Inject page fault into the guest	
+    inject_guest_pf(info, fault_addr, error_code);
+    PrintError("PTE Page fault fell through... Not sure if this should ever happen\n");
+    PrintError("Manual Says to inject page fault into guest\n");
+    return -1;
+  }
+
+  PrintDebug("Returning end of function\n");
+  return 0;
+}
diff --git a/palacios/src/palacios/vmm_shadow_paging_32pae.h b/palacios/src/palacios/vmm_shadow_paging_32pae.h
new file mode 100644
index 0000000..58a4300
--- /dev/null
+++ b/palacios/src/palacios/vmm_shadow_paging_32pae.h
@@ -0,0 +1,30 @@
+
+
+
+static int activate_shadow_pt_32pae(struct guest_info * info) {
+  PrintError("Activating 32 bit PAE page tables not implemented\n");
+  return -1;
+}
+
+
+
+
+
+
+/* 
+ * *
+ * * 
+ * * 32 bit PAE  Page table fault handlers
+ * *
+ * *
+ */
+
+static int handle_shadow_pagefault_32pae(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) {
+  PrintError("32 bit PAE shadow paging not implemented\n");
+  return -1;
+}
+
+
+
+
+
diff --git a/palacios/src/palacios/vmm_shadow_paging_64.h b/palacios/src/palacios/vmm_shadow_paging_64.h
new file mode 100644
index 0000000..685ed61
--- /dev/null
+++ b/palacios/src/palacios/vmm_shadow_paging_64.h
@@ -0,0 +1,38 @@
+
+static int activate_shadow_pt_64(struct guest_info * info) {
+  //  struct cr3_64 * shadow_cr3 = (struct cr3_64 *)&(info->ctrl_regs.cr3);
+ 
+  return -1;
+}
+
+
+
+
+
+
+/* 
+ * *
+ * * 
+ * * 64 bit Page table fault handlers
+ * *
+ * *
+ */
+
+static int handle_shadow_pagefault_64(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) {
+  pt_access_status_t guest_access;
+  pt_access_status_t shadow_access;
+  int ret; 
+  PrintDebug("64 bit shadow page fault\n");
+
+  ret = v3_check_guest_pt_32(info, info->shdw_pg_state.guest_cr3, fault_addr, error_code, &guest_access);
+
+  PrintDebug("Guest Access Check: %d (access=%d)\n", ret, guest_access);
+
+  ret = v3_check_host_pt_32(info->ctrl_regs.cr3, fault_addr, error_code, &shadow_access);
+
+  PrintDebug("Shadow Access Check: %d (access=%d)\n", ret, shadow_access);
+  
+
+  PrintError("64 bit shadow paging not implemented\n");
+  return -1;
+}