Changeset 74455 in vbox for trunk

Timestamp:

Sep 25, 2018 11:18:05 AM (6 years ago)

Author:

vboxsync

Message:

VMX: Also enforce RM compatible attributes before using real-on-V86 execution.

Location:

trunk/src/VBox/VMM

Files:

• VMMAll/HMVMXAll.cpp (modified) (2 diffs)
• VMMR3/HM.cpp (modified) (1 diff)
• include/HMInternal.h (modified) (1 diff)

trunk/src/VBox/VMM/VMMAll/HMVMXAll.cpp

@@ -658 +658 @@
                 /*
                  * In V86 mode (VT-x or not), the CPU enforces real-mode compatible selector
-                 * bases and limits, i.e. limit must be 64K and base must be selector * 16.
+                 * bases, limits, and attributes, i.e. limit must be 64K, base must be selector * 16,
+                 * and attrributes must be 0x9b for code and 0x93 for code segments.
                  * If this is not true, we cannot execute real mode as V86 and have to fall
                  * back to emulation.
@@ -680 +681 @@
                 {
                     STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxCheckBadRmSelLimit);
+                    return false;
+                }
+                if (   (pCtx->cs.Attr.u != 0x9b)
+                    || (pCtx->ds.Attr.u != 0x93)
+                    || (pCtx->es.Attr.u != 0x93)
+                    || (pCtx->ss.Attr.u != 0x93)
+                    || (pCtx->fs.Attr.u != 0x93)
+                    || (pCtx->gs.Attr.u != 0x93))
+                {
+                    STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxCheckBadRmSelAttr);
                     return false;
                 }

trunk/src/VBox/VMM/VMMR3/HM.cpp

@@ -1049 +1049 @@
         HM_REG_COUNTER(&pVCpu->hm.s.StatVmxCheckBadRmSelBase,   "/HM/CPU%d/VMXCheck/RMSelBase", "Could not use VMX due to unsuitable real-mode selector base.");
         HM_REG_COUNTER(&pVCpu->hm.s.StatVmxCheckBadRmSelLimit,  "/HM/CPU%d/VMXCheck/RMSelLimit", "Could not use VMX due to unsuitable real-mode selector limit.");
+        HM_REG_COUNTER(&pVCpu->hm.s.StatVmxCheckBadRmSelAttr,   "/HM/CPU%d/VMXCheck/RMSelAttrs", "Could not use VMX due to unsuitable real-mode selector limit.");
         HM_REG_COUNTER(&pVCpu->hm.s.StatVmxCheckRmOk,           "/HM/CPU%d/VMXCheck/VMX_RM", "VMX execution in real (V86) mode OK.");
         HM_REG_COUNTER(&pVCpu->hm.s.StatVmxCheckBadSel,         "/HM/CPU%d/VMXCheck/Selector", "Could not use VMX due to unsuitable selector.");

trunk/src/VBox/VMM/include/HMInternal.h

@@ -1039 +1039 @@
     STAMCOUNTER             StatVmxCheckBadRmSelBase;
     STAMCOUNTER             StatVmxCheckBadRmSelLimit;
+    STAMCOUNTER             StatVmxCheckBadRmSelAttr;
     STAMCOUNTER             StatVmxCheckRmOk;
     STAMCOUNTER             StatVmxCheckBadSel;