X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=blobdiff_plain;f=palacios%2Fsrc%2Fpalacios%2Fvmm_shadow_paging.c;h=0690f66a607cff971321cf95ae0f417695f165af;hb=da0f0deecf22754656bad2a95640461ec3ac4f1d;hp=d11f85f7721a43bf29c2c85b635dadd0d1b7f8d4;hpb=a71d13e84ccd2ea959299c7f01513e6f9e593b7d;p=palacios.git

diff --git a/palacios/src/palacios/vmm_shadow_paging.c b/palacios/src/palacios/vmm_shadow_paging.c
index d11f85f..0690f66 100644
--- a/palacios/src/palacios/vmm_shadow_paging.c
+++ b/palacios/src/palacios/vmm_shadow_paging.c
@@ -26,6 +26,8 @@
 #include <palacios/vmm_decoder.h>
 #include <palacios/vmm_ctrl_regs.h>
 
+#include <palacios/vmm_hashtable.h>
+
 #ifndef DEBUG_SHADOW_PAGING
 #undef PrintDebug
 #define PrintDebug(fmt, args...)
@@ -37,6 +39,26 @@
  ***/
 
 
+struct guest_table {
+  addr_t cr3;
+  struct list_head link;
+};
+
+
+struct backptr {
+  addr_t ptr;
+  struct list_head link;
+};
+
+
+struct shadow_page_data {
+  addr_t ptr;
+  addr_t guest_addr; 
+
+  struct list_head backptrs;
+  struct list_head guest_tables;
+};
+
 
 
 
@@ -78,6 +100,10 @@ static int handle_shadow_pagefault_32(struct guest_info * info, addr_t fault_add
 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);
   
@@ -95,67 +121,17 @@ int v3_init_shadow_page_state(struct guest_info * info) {
 
 
 
-/*
- For now we'll do something a little more lightweight
-int cache_page_tables32(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;
-
-
-  pte_cache = (struct hashtable *)find_cr3_in_cache(state->cr3_cache, pde);
-  if (pte_cache != NULL) {
-    PrintError("CR3 already present in cache\n");
-    state->current_ptes = pte_cache;
-    return 1;
-  } else {
-    PrintError("Creating new CR3 cache entry\n");
-    pte_cache = create_hashtable(0, &pte_hash_fn, &pte_equals);
-    state->current_ptes = pte_cache;
-    add_cr3_to_cache(state->cr3_cache, pde, 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)(PDE32_T_ADDR(tmp_pde[i])), &pte_host_addr) == -1) {
-	PrintError("Could not lookup host address of guest PDE\n");
-	return -1;
-      }
-
-      add_pte_map(pte_cache, (addr_t)(PDE32_T_ADDR(tmp_pde[i])), pte_host_addr); 
-    }
-  }
-
-
-  return 0;
-}
-*/
-
 
 int v3_cache_page_tables(struct guest_info * info, addr_t cr3) {
   switch(v3_get_cpu_mode(info)) {
   case PROTECTED:
-    return v3_cache_page_tables32(info, CR3_TO_PDE32_PA(cr3));
+    return cache_page_tables_32(info, CR3_TO_PDE32_PA(cr3));
   default:
     return -1;
   }
 }
 
-int v3_cache_page_tables32(struct guest_info * info, addr_t pde) {
+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;
@@ -204,6 +180,10 @@ int v3_cache_page_tables32(struct guest_info * info, addr_t pde) {
 }
 
 
+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);
@@ -221,6 +201,7 @@ int v3_replace_shdw_page32(struct guest_info * info, addr_t location, pte32_t *
 
   } else {
     // currently unhandled
+    PrintError("Replacing large shadow pages not implemented\n");
     return -1;
   }
   
@@ -234,34 +215,34 @@ int v3_replace_shdw_page32(struct guest_info * info, addr_t location, pte32_t *
 // 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 = v3_cache_page_tables32(info, CR3_TO_PDE32_PA(*(addr_t *)guest_cr3));
+  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;
     
-    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;
+    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) {
@@ -269,9 +250,49 @@ static int activate_shadow_pt_32pae(struct guest_info * info) {
   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) {
-  PrintError("Activating 64 bit page tables not implemented\n");
+  //  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;
+		      */
 }
 
 
@@ -316,7 +337,8 @@ int v3_handle_shadow_pagefault(struct guest_info * info, addr_t fault_addr, pf_e
     // If paging is not turned on we need to handle the special cases
 
 #ifdef DEBUG_SHADOW_PAGING
-    PrintPageTree(info->cpu_mode, fault_addr, info->ctrl_regs.cr3);
+    PrintHostPageTree(info->cpu_mode, fault_addr, info->ctrl_regs.cr3);
+    PrintGuestPageTree(info, fault_addr, info->shdw_pg_state.guest_cr3);
 #endif
 
     return handle_special_page_fault(info, fault_addr, fault_addr, error_code);
@@ -400,6 +422,20 @@ static int is_guest_pf(pt_access_status_t guest_access, pt_access_status_t shado
  */
 
 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;
 }
@@ -564,9 +600,9 @@ static int handle_shadow_pagefault_32(struct guest_info * info, addr_t fault_add
       PrintDebug("Manual Says to inject page fault into guest\n");
 #ifdef DEBUG_SHADOW_PAGING
       PrintDebug("Guest PDE: (access=%d)\n\t", guest_pde_access);
-      PrintPDE32(fault_addr, guest_pde);
+      PrintPTEntry(PAGE_PD32, fault_addr, guest_pde);
       PrintDebug("Shadow PDE: (access=%d)\n\t", shadow_pde_access);
-      PrintPDE32(fault_addr, shadow_pde);
+      PrintPTEntry(PAGE_PD32, fault_addr, shadow_pde);
 #endif
 
       return 0; 
@@ -587,7 +623,8 @@ static int handle_large_pagefault_32(struct guest_info * info,
 {
   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);  
+
   if (shadow_pte_access == PT_ACCESS_OK) {
     // Inconsistent state...
     // Guest Re-Entry will flush tables and everything should now workd
@@ -598,18 +635,18 @@ static int handle_large_pagefault_32(struct guest_info * info,
   
   if (shadow_pte_access == PT_ACCESS_NOT_PRESENT) {
     // Get the guest physical address of the fault
-    addr_t guest_fault_pa = BASE_TO_PAGE_ADDR_4MB(large_guest_pde->page_base_addr) + PAGE_OFFSET_4MB(fault_addr);
-    host_region_type_t host_page_type = get_shadow_addr_type(info, guest_fault_pa);
+    shdw_region_type_t host_page_type = get_shadow_addr_type(info, guest_fault_pa);
  
 
-    if (host_page_type == HOST_REGION_INVALID) {
+    if (host_page_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 0;
     }
 
-    if (host_page_type == HOST_REGION_PHYSICAL_MEMORY) {
+    if ((host_page_type == SHDW_REGION_ALLOCATED) || 
+	(host_page_type == SHDW_REGION_WRITE_HOOK)) {
       struct shadow_page_state * state = &(info->shdw_pg_state);
       addr_t shadow_pa = get_shadow_addr(info, guest_fault_pa);
 
@@ -629,11 +666,12 @@ static int handle_large_pagefault_32(struct guest_info * info,
 	PrintDebug("Marking page as Guest Page Table (large page)\n");
 	shadow_pte->vmm_info = PT32_GUEST_PT;
 	shadow_pte->writable = 0;
+      } else if (host_page_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;
@@ -642,18 +680,30 @@ static int handle_large_pagefault_32(struct guest_info * info,
       
     } 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 (handle_special_page_fault(info, fault_addr, guest_fault_pa, error_code) == -1) {
+      struct shadow_region * reg = v3_get_shadow_region(info, guest_fault_pa);
+
+      if (v3_handle_mem_full_hook(info, fault_addr, guest_fault_pa, 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) && 
-	     (shadow_pte->vmm_info == PT32_GUEST_PT)) {
+  } else if (shadow_pte_access == PT_ACCESS_WRITE_ERROR) {
+    shdw_region_type_t host_page_type = get_shadow_addr_type(info, guest_fault_pa);
+
+    if (host_page_type == SHDW_REGION_WRITE_HOOK) {
+      struct shadow_region * reg = v3_get_shadow_region(info, guest_fault_pa);
 
-    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;
+      if (v3_handle_mem_wr_hook(info, fault_addr, guest_fault_pa, 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");
@@ -681,6 +731,7 @@ static int handle_shadow_pte32_fault(struct guest_info * info,
   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);
 
 
   // Check the guest page permissions
@@ -691,9 +742,9 @@ static int handle_shadow_pte32_fault(struct guest_info * info,
   
 #ifdef DEBUG_SHADOW_PAGING
   PrintDebug("Guest PTE: (access=%d)\n\t", guest_pte_access);
-  PrintPTE32(fault_addr, guest_pte);
+  PrintPTEntry(PAGE_PT32, fault_addr, guest_pte);
   PrintDebug("Shadow PTE: (access=%d)\n\t", shadow_pte_access);
-  PrintPTE32(fault_addr, shadow_pte);
+  PrintPTEntry(PAGE_PT32, fault_addr, shadow_pte);
 #endif
   
   /* Was the page fault caused by the Guest's page tables? */
@@ -715,14 +766,13 @@ static int handle_shadow_pte32_fault(struct guest_info * info,
 
   if (shadow_pte_access == PT_ACCESS_NOT_PRESENT) {
 
-    addr_t guest_pa = BASE_TO_PAGE_ADDR((addr_t)(guest_pte->page_base_addr)) +  PAGE_OFFSET(fault_addr);
 
     // Page Table Entry Not Present
     PrintDebug("guest_pa =%p\n", (void *)guest_pa);
 
-    host_region_type_t host_page_type = get_shadow_addr_type(info, guest_pa);
+    shdw_region_type_t host_page_type = get_shadow_addr_type(info, guest_pa);
 
-    if (host_page_type == HOST_REGION_INVALID) {
+    if (host_page_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);
@@ -731,7 +781,8 @@ static int handle_shadow_pte32_fault(struct guest_info * info,
 
     // else...
 
-    if (host_page_type == HOST_REGION_PHYSICAL_MEMORY) {
+    if ((host_page_type == SHDW_REGION_ALLOCATED) ||
+	(host_page_type == SHDW_REGION_WRITE_HOOK)) {
       struct shadow_page_state * state = &(info->shdw_pg_state);
       addr_t shadow_pa = get_shadow_addr(info, guest_pa);
       
@@ -754,7 +805,9 @@ static int handle_shadow_pte32_fault(struct guest_info * info,
 	shadow_pte->vmm_info = PT32_GUEST_PT;
       }
 
-      if (guest_pte->dirty == 1) {
+      if (host_page_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;
@@ -771,29 +824,42 @@ static int handle_shadow_pte32_fault(struct guest_info * info,
 	shadow_pte->writable = 0;
       }
 
-
-
     } else {
       // Page fault handled by hook functions
-      if (handle_special_page_fault(info, fault_addr, guest_pa, error_code) == -1) {
+      struct shadow_region * reg = v3_get_shadow_region(info, guest_pa);
+
+      if (v3_handle_mem_full_hook(info, fault_addr, guest_pa, 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)) {
-
-    PrintDebug("Shadow PTE Write Error\n");
+    */
+  } else if (shadow_pte_access == PT_ACCESS_WRITE_ERROR) {
     guest_pte->dirty = 1;
-    shadow_pte->writable = guest_pte->writable;
+
+    shdw_region_type_t host_page_type = get_shadow_addr_type(info, guest_pa);
+
+    if (host_page_type == SHDW_REGION_WRITE_HOOK) {
+      struct shadow_region * reg = v3_get_shadow_region(info, guest_pa);
+
+      if (v3_handle_mem_wr_hook(info, fault_addr, guest_pa, 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 {
@@ -825,7 +891,8 @@ int v3_handle_shadow_invlpg(struct guest_info * info)
   
   
   if (info->cpu_mode != PROTECTED) {
-    return 0;
+    PrintError("Unsupported CPU mode (mode=%s)\n", v3_cpu_mode_to_str(info->cpu_mode));
+    return -1;
   }
   
   uchar_t instr[15];
@@ -892,7 +959,7 @@ int v3_handle_shadow_invlpg(struct guest_info * info)
       
 #ifdef DEBUG_SHADOW_PAGING
       PrintDebug("Setting not present\n");
-      PrintPTE32(first_operand, shadow_pte );
+      PrintPTEntry(PAGE_PT32, first_operand, shadow_pte);
 #endif
       
       shadow_pte->present = 0;
@@ -904,133 +971,3 @@ int v3_handle_shadow_invlpg(struct guest_info * info)
 }
 
 
-/*
-
-
-static int create_pd32_nonaligned_4MB_page(struct guest_info * info, pte32_t * pt, addr_t guest_addr, pde32_4MB_t * large_shadow_pde) {
-  uint_t i = 0;
-  pte32_t * pte_cursor;
-  addr_t guest_pa = 0;
-
-  for (i = 0; i < 1024; i++) {
-    guest_pa = guest_addr + (PAGE_SIZE * i);
-    host_region_type_t host_page_type = get_shadow_addr_type(info, guest_pa);
-    
-    pte_cursor = &(pt[i]);
-
-    if (host_page_type == HOST_REGION_INVALID) {
-      // Currently we don't support this, but in theory we could
-      PrintError("Invalid Host Memory Type\n");
-      return -1;
-    } else if (host_page_type == HOST_REGION_PHYSICAL_MEMORY) {
-      addr_t shadow_pa = get_shadow_addr(info, guest_pa);
-
-
-      pte_cursor->page_base_addr = PT32_BASE_ADDR(shadow_pa);
-      pte_cursor->present = 1;
-      pte_cursor->writable = large_shadow_pde->writable;
-      pte_cursor->user_page = large_shadow_pde->user_page;
-      pte_cursor->write_through = 0;  
-      pte_cursor->cache_disable = 0;
-      pte_cursor->global_page = 0;
-
-    } else {
-      PrintError("Unsupported Host Memory Type\n");
-      return -1;
-    }
-  }
-  return 0;
-}
-
-
-static int handle_large_pagefault32(struct guest_info * info, 
-				    pde32_t * guest_pde, pde32_t * shadow_pde, 
-				    addr_t fault_addr, pf_error_t error_code ) {
-  struct shadow_region * mem_reg;
-  pde32_4MB_t * large_guest_pde = (pde32_4MB_t *)guest_pde;
-  pde32_4MB_t * large_shadow_pde = (pde32_4MB_t *)shadow_pde;
-  host_region_type_t host_page_type;
-  addr_t guest_start_addr = PDE32_4MB_T_ADDR(*large_guest_pde);
-  //    addr_t guest_end_addr = guest_start_addr + PAGE_SIZE_4MB; // start address + 4MB
-  
-  
-  // Check that the Guest PDE entry points to valid memory
-  // else Machine Check the guest
-  PrintDebug("Large Page: Page Base Addr=%x\n", guest_start_addr);
-  
-  host_page_type = get_shadow_addr_type(info, guest_start_addr);
-  
-  if (host_page_type == HOST_REGION_INVALID) {
-    PrintError("Invalid guest address in large page (0x%x)\n", guest_start_addr);
-    v3_raise_exception(info, MC_EXCEPTION);
-    return -1;
-  }
-  
-  // else...
-
-  if (host_page_type == HOST_REGION_PHYSICAL_MEMORY) {
-
-    addr_t host_start_addr = 0;
-    addr_t region_end_addr = 0;
-    
-    // Check for a large enough region in host memory
-    mem_reg = get_shadow_region_by_addr(&(info->mem_map), guest_start_addr);
-    PrintDebug("Host region: host_addr=%x (guest_start=%x, end=%x)\n", 
-	       mem_reg->host_addr, mem_reg->guest_start, mem_reg->guest_end);
-    host_start_addr = mem_reg->host_addr + (guest_start_addr - mem_reg->guest_start);
-    region_end_addr = mem_reg->host_addr + (mem_reg->guest_end - mem_reg->guest_start);
-    
-    PrintDebug("Host Start Addr=%x; Region End Addr=%x\n", host_start_addr, region_end_addr);
-    
-    
-    //4f
-    if (large_guest_pde->dirty == 1) { // dirty
-      large_shadow_pde->writable = guest_pde->writable;
-    } else if (error_code.write == 1) { // not dirty, access is write
-      large_shadow_pde->writable = guest_pde->writable;
-      large_guest_pde->dirty = 1;
-    } else { // not dirty, access is read
-      large_shadow_pde->writable = 0;
-    }
-    
-    
-    // Check if the region is at least an additional 4MB
-    
-    
-    //4b.
-    if ((PD32_4MB_PAGE_OFFSET(host_start_addr) == 0) && 
-	(region_end_addr >= host_start_addr + PAGE_SIZE_4MB)) { 	// if 4MB boundary
-      large_shadow_pde->page_base_addr = PD32_4MB_BASE_ADDR(host_start_addr);
-    } else { 	  // else generate 4k pages
-      pte32_t * shadow_pt = NULL;
-      PrintDebug("Handling non aligned large page\n");
-      
-      shadow_pde->large_page = 0;
-      
-      shadow_pt = create_new_shadow_pt32();
-
-      if (create_pd32_nonaligned_4MB_page(info, shadow_pt, guest_start_addr, large_shadow_pde) == -1) {
-	PrintError("Non Aligned Large Page Error\n");
-	V3_Free(shadow_pt);
-	return -1;
-      }
-      
-      
-#ifdef DEBUG_SHADOW_PAGING
-      PrintDebug("non-aligned Shadow PT\n");
-      PrintPT32(PT32_PAGE_ADDR(fault_addr), shadow_pt);	  
-#endif
-      shadow_pde->pt_base_addr = PD32_BASE_ADDR(shadow_pt);
-    }
-    
-  } else {
-    // Handle hooked pages as well as other special pages
-    if (handle_special_page_fault(info, fault_addr, guest_start_addr, error_code) == -1) {
-      PrintError("Special Page Fault handler returned error for address: %x\n", fault_addr);
-      return -1;
-    }
-  }
-
-  return 0;
-}
-*/