Changeset 62106 in vbox for trunk/src

Timestamp:

Jul 7, 2016 2:24:52 PM (9 years ago)

Author:

vboxsync

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

108588

Message:

hmR0VmxIs32BitSwitcherSafe: Use return, it's one of the major perks implementing a predicate function as a function. Corrected docs.

File:

• trunk/src/VBox/VMM/VMMR0/HMVMXR0.cpp (modified) (2 diffs)

trunk/src/VBox/VMM/VMMR0/HMVMXR0.cpp

@@ -4824 +4824 @@
 
 
-#if HC_ARCH_BITS == 32
-# ifdef VBOX_ENABLE_64_BITS_GUESTS
+#if HC_ARCH_BITS == 32 && defined(VBOX_ENABLE_64_BITS_GUESTS)
 /**
  * Check if guest state allows safe use of 32-bit switcher again.
  *
- * @returns VBox status code.
+ * Segment bases and protected mode structures must be 32-bit addressable
+ * because the  32-bit switcher will ignore high dword when writing these VMCS
+ * fields.  See @bugref{8432} for details.
+ *
+ * @returns true if safe, false if must continue to use the 64-bit switcher.
  * @param   pVCpu       The cross context virtual CPU structure.
  * @param   pMixedCtx   Pointer to the guest-CPU context. The data may be
@@ -4839 +4842 @@
 static bool hmR0VmxIs32BitSwitcherSafe(PVMCPU pVCpu, PCPUMCTX pMixedCtx)
 {
-    bool    rc = false;
-
-    do
-    {
-        if (pMixedCtx->gdtr.pGdt & UINT64_C(0xffffffff00000000))
-            break;
-        if (pMixedCtx->idtr.pIdt & UINT64_C(0xffffffff00000000))
-            break;
-        if (pMixedCtx->ldtr.u64Base & UINT64_C(0xffffffff00000000))
-            break;
-        if (pMixedCtx->tr.u64Base & UINT64_C(0xffffffff00000000))
-            break;
-        if (pMixedCtx->es.u64Base & UINT64_C(0xffffffff00000000))
-            break;
-        if (pMixedCtx->cs.u64Base & UINT64_C(0xffffffff00000000))
-            break;
-        if (pMixedCtx->ss.u64Base & UINT64_C(0xffffffff00000000))
-            break;
-        if (pMixedCtx->ds.u64Base & UINT64_C(0xffffffff00000000))
-            break;
-        if (pMixedCtx->fs.u64Base & UINT64_C(0xffffffff00000000))
-            break;
-        if (pMixedCtx->gs.u64Base & UINT64_C(0xffffffff00000000))
-            break;
-        /* All good, bases are 32-bit. */
-        rc = true;
-    } while (0);
-
-    return rc;
-}
-# endif
+    if (pMixedCtx->gdtr.pGdt    & UINT64_C(0xffffffff00000000))
+        return false;
+    if (pMixedCtx->idtr.pIdt    & UINT64_C(0xffffffff00000000))
+        return false;
+    if (pMixedCtx->ldtr.u64Base & UINT64_C(0xffffffff00000000))
+        return false;
+    if (pMixedCtx->tr.u64Base   & UINT64_C(0xffffffff00000000))
+        return false;
+    if (pMixedCtx->es.u64Base   & UINT64_C(0xffffffff00000000))
+        return false;
+    if (pMixedCtx->cs.u64Base   & UINT64_C(0xffffffff00000000))
+        return false;
+    if (pMixedCtx->ss.u64Base   & UINT64_C(0xffffffff00000000))
+        return false;
+    if (pMixedCtx->ds.u64Base   & UINT64_C(0xffffffff00000000))
+        return false;
+    if (pMixedCtx->fs.u64Base   & UINT64_C(0xffffffff00000000))
+        return false;
+    if (pMixedCtx->gs.u64Base   & UINT64_C(0xffffffff00000000))
+        return false;
+    /* All good, bases are 32-bit. */
+    return true;
+}
 #endif