Changeset 810 in vbox

Timestamp:

Feb 9, 2007 2:24:48 PM (18 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

18486

Message:

Paranoid own bit checks in TMD & RMD reads.

File:

• trunk/src/VBox/Devices/Network/DevPCNet.cpp (modified) (6 diffs)

trunk/src/VBox/Devices/Network/DevPCNet.cpp

@@ -589 +589 @@
 /**
  * Load transmit message descriptor
+ * Make sure we read the own flag first.
  */
 DECLINLINE(void) pcnetTmdLoad(PCNetState *pData, TMD *tmd, RTGCPHYS addr)
 {
     PPDMDEVINS pDevIns = PCNETSTATE_2_DEVINS(pData);
+    uint8_t    ownbyte;
+
     if (!BCR_SWSTYLE(pData))
     {
         uint16_t xda[4];
+
+        PDMDevHlpPhysRead(pDevIns, addr+3, &ownbyte, 1);
         PDMDevHlpPhysRead(pDevIns, addr, (void*)&xda[0], sizeof(xda));
         ((uint32_t *)tmd)[0] = (uint32_t)xda[0] | ((uint32_t)(xda[1] & 0x00ff) << 16);
@@ -603 +608 @@
     }
     else if (BCR_SWSTYLE(pData) != 3)
+    {
+        PDMDevHlpPhysRead(pDevIns, addr+7, &ownbyte, 1);
         PDMDevHlpPhysRead(pDevIns, addr, (void*)tmd, 16);
+    }
     else
     {
         uint32_t xda[4];
+        PDMDevHlpPhysRead(pDevIns, addr+7, &ownbyte, 1);
         PDMDevHlpPhysRead(pDevIns, addr, (void*)&xda[0], sizeof(xda));
         ((uint32_t *)tmd)[0] = xda[2];
@@ -613 +622 @@
         ((uint32_t *)tmd)[3] = xda[3];
     }
+    /* Double check the own bit; guest drivers might be buggy and lock prefixes in the recompiler are ignored by other threads. */
+#ifdef DEBUG
+    if (tmd->tmd1.own == 0 && (ownbyte & 0x80))
+        Log(("pcnetTmdLoad: own bit flipped while reading!!\n"));
+#endif
+    if (ownbyte & 0x80)
+        tmd->tmd1.own = 1;
 }
 
@@ -663 +679 @@
 {
     PPDMDEVINS pDevIns = PCNETSTATE_2_DEVINS(pData);
+    uint8_t    ownbyte;
+
     if (!BCR_SWSTYLE(pData))
     {
         uint16_t rda[4];
+        PDMDevHlpPhysRead(pDevIns, addr+3, &ownbyte, 1);
         PDMDevHlpPhysRead(pDevIns, addr, (void*)&rda[0], sizeof(rda));
         ((uint32_t *)rmd)[0] = (uint32_t)rda[0] | ((rda[1] & 0x00ff) << 16);
@@ -673 +692 @@
     }
     else if (BCR_SWSTYLE(pData) != 3)
+    {
+        PDMDevHlpPhysRead(pDevIns, addr+7, &ownbyte, 1);
         PDMDevHlpPhysRead(pDevIns, addr, (void*)rmd, 16);
+    }
     else
     {
         uint32_t rda[4];
+        PDMDevHlpPhysRead(pDevIns, addr+7, &ownbyte, 1);
         PDMDevHlpPhysRead(pDevIns, addr, (void*)&rda[0], sizeof(rda));
         ((uint32_t *)rmd)[0] = rda[2];
@@ -683 +706 @@
         ((uint32_t *)rmd)[3] = rda[3];
     }
+    /* Double check the own bit; guest drivers might be buggy and lock prefixes in the recompiler are ignored by other threads. */
+#ifdef DEBUG
+    if (rmd->rmd1.own == 0 && (ownbyte & 0x80))
+        Log(("pcnetTmdLoad: own bit flipped while reading!!\n"));
+#endif
+    if (ownbyte & 0x80)
+        rmd->rmd1.own = 1;
 }