Corrected corner case in VTLB (shadow paging) handling

diff --git a/palacios/src/palacios/mmu/vmm_shdw_pg_tlb_64.h b/palacios/src/palacios/mmu/vmm_shdw_pg_tlb_64.h
index 0d809af..334c675 100644 (file)
--- a/palacios/src/palacios/mmu/vmm_shdw_pg_tlb_64.h
+++ b/palacios/src/palacios/mmu/vmm_shdw_pg_tlb_64.h
@@ -390,7 +390,21 @@ static int handle_pde_shadow_pagefault_64(struct guest_info * info, addr_t fault
        guest_pde->accessed = 1;
     
        shadow_pde->pt_base_addr = PAGE_BASE_ADDR(shdw_page->page_pa);
-    } else {
+    } else { // when PT_ACCESS_OK is true
+       if ((info->use_large_pages == 1) && (guest_pde->large_page == 1) ) {
+           addr_t guest_pa = BASE_TO_PAGE_ADDR_4MB(((pde32_4MB_t *)guest_pde)->page_base_addr);
+           uint32_t page_size = v3_get_max_page_size(info, guest_pa, LONG);   
+           if (page_size == PAGE_SIZE_2MB)   {
+               if (shadow_pde_access == PT_ACCESS_OK) {
+                   // Inconsistent state...
+                   // Guest Re-Entry will flush tables and everything should now workd
+                   PrintDebug(info->vm_info, info, "Inconsistent state PDE... Guest re-entry should flush tlb\n");
+                    //PrintDebug(info->vm_info, info, "Bug here: shadow_pde_access is %d page_size is %d\n",
+                   //     (uint_t)shadow_pde_access,(uint_t)page_size);
+                   return 0;
+               }
+           } 
+       }
        shadow_pt = (pte64_t *)V3_VAddr((void *)BASE_TO_PAGE_ADDR(shadow_pde->pt_base_addr));
     }
 
@@ -583,14 +597,17 @@ static int handle_2MB_shadow_pagefault_pde_64(struct guest_info * info,
        return 0;
     }
 
+    /* Note that this handler is currently invoked only when PT_ACCESS_OK is PT_NOT_PRESENT. */
     if (shadow_pde_access == PT_ACCESS_OK) {
        // Inconsistent state...
        // Guest Re-Entry will flush tables and everything should now workd
        PrintDebug(info->vm_info, info, "Inconsistent state... Guest re-entry should flush tlb\n");
+        PrintError(info->vm_info, info, "Hmm... did not expect call to this handler with PT_ACCESS_OK to happen...\n");
        //PrintHostPageTree(info, fault_addr, info->ctrl_regs.cr3);
        return 0;
     }
 
+
   
     if (shadow_pde_access == PT_ACCESS_NOT_PRESENT) {
        // Get the guest physical address of the fault