From: Peter Dinda <pdinda@northwestern.edu>
Date: Tue, 29 Mar 2011 22:23:36 +0000 (-0500)
Subject: Changed semantics of guest page table drilling
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=commitdiff_plain;h=201c3bb9d4fa7606dbd3193baf408f29142381d1;p=palacios.releases.git

Changed semantics of guest page table drilling
Now a drill that terminates in guest data page that is not backed by
physical memory does not fail.  Instead, the relevant hva will be
returned as zero.   This change is needed to support some new lookups,
like gva_to_gpa where the gpa is in the middle of a full hook region

The previous semantics (fail when the above occurs) does not appear
to be used anywhere, so this change should not be consequential.
---

diff --git a/palacios/src/palacios/vmm_paging.c b/palacios/src/palacios/vmm_paging.c
index 05d1025..ec91056 100644
--- a/palacios/src/palacios/vmm_paging.c
+++ b/palacios/src/palacios/vmm_paging.c
@@ -971,9 +971,7 @@ int v3_drill_guest_pt_32(struct guest_info * info, v3_reg_t guest_cr3, addr_t va
 		addr_t large_page_va = 0;
       
 		if (v3_gpa_to_hva(info, large_page_pa, &large_page_va) == -1) {
-		    PrintError("Could not get virtual address of Guest Page 4MB (PA=%p)\n", 
-			       (void *)large_page_va);
-		    return -1;
+		    large_page_va = 0 ;
 		}
 
 
@@ -1003,9 +1001,7 @@ int v3_drill_guest_pt_32(struct guest_info * info, v3_reg_t guest_cr3, addr_t va
 		    addr_t page_va;
 
 		    if (v3_gpa_to_hva(info, page_pa, &page_va) == -1) {
-			PrintError("Could not get virtual address of Guest Page 4KB (PA=%p)\n", 
-				   (void *)page_pa);
-			return -1;
+			page_va = 0;
 		    }
 
 		    if ((ret = callback(info, PAGE_4KB, vaddr, page_va, page_pa, private_data)) != 0) {
@@ -1070,9 +1066,7 @@ int v3_drill_guest_pt_32pae(struct guest_info * info, v3_reg_t guest_cr3, addr_t
 				    addr_t large_page_va = 0;
 	      
 				    if (v3_gpa_to_hva(info, large_page_pa, &large_page_va) == -1) {
-					PrintDebug("Could not get virtual address of Guest Page 2MB (PA=%p)\n", 
-						   (void *)large_page_va);
-
+					large_page_va = 0;
 				    }
 	      
 				    if ((ret == callback(info, PAGE_2MB, vaddr, large_page_va, large_page_pa, private_data)) != 0) {
@@ -1101,9 +1095,7 @@ int v3_drill_guest_pt_32pae(struct guest_info * info, v3_reg_t guest_cr3, addr_t
 					addr_t page_va;
 		
 					if (v3_gpa_to_hva(info, page_pa, &page_va) == -1) {
-					    PrintError("Could not get virtual address of Guest Page 4KB (PA=%p)\n", 
-						       (void *)page_pa);
-					    return -1;
+					    page_va = 0;
 					}
 		
 					if ((ret = callback(info, PAGE_4KB, vaddr, page_va, page_pa, private_data)) != 0) {
@@ -1169,9 +1161,7 @@ int v3_drill_guest_pt_64(struct guest_info * info, v3_reg_t guest_cr3, addr_t va
 			    addr_t large_page_va = 0;
 	  
 			    if (v3_gpa_to_hva(info, large_page_pa, &large_page_va) == -1) {
-				PrintDebug("Could not get virtual address of Guest Page 1GB (PA=%p)\n", 
-					   (void *)large_page_va);
-	    
+				large_page_va = 0;
 			    }
 	  
 			    if ((ret == callback(info, PAGE_1GB, vaddr, large_page_va, large_page_pa, private_data)) != 0) {
@@ -1204,9 +1194,7 @@ int v3_drill_guest_pt_64(struct guest_info * info, v3_reg_t guest_cr3, addr_t va
 					addr_t large_page_va = 0;
 	      
 					if (v3_gpa_to_hva(info, large_page_pa, &large_page_va) == -1) {
-					    PrintDebug("Could not get virtual address of Guest Page 2MB (PA=%p)\n", 
-						       (void *)large_page_va);
-
+					    large_page_va = 0;
 					}
 	      
 					if ((ret == callback(info, PAGE_2MB, vaddr, large_page_va, large_page_pa, private_data)) != 0) {
@@ -1235,9 +1223,7 @@ int v3_drill_guest_pt_64(struct guest_info * info, v3_reg_t guest_cr3, addr_t va
 					    addr_t page_va;
 		
 					    if (v3_gpa_to_hva(info, page_pa, &page_va) == -1) {
-						PrintError("Could not get virtual address of Guest Page 4KB (PA=%p)\n", 
-							   (void *)page_pa);
-						return -1;
+						page_va = 0;
 					    }
 		
 					    if ((ret = callback(info, PAGE_4KB, vaddr, page_va, page_pa, private_data)) != 0) {