Changeset 77325 in vbox

Timestamp:

Feb 15, 2019 7:55:09 AM (6 years ago)

Author:

vboxsync

Message:

VMM/HM: Added V8086 mode checks to HMCanExecuteVmxGuest.

Location:

trunk/src/VBox/VMM

Files:

• VMMAll/HMVMXAll.cpp (modified) (3 diffs)
• VMMR3/HM.cpp (modified) (1 diff)
• include/HMInternal.h (modified) (1 diff)

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

@@ -672 +672 @@
                  * In V86 mode (VT-x or not), the CPU enforces real-mode compatible selector
                  * 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.
+                 * and attributes 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.
@@ -717 +717 @@
                 if (pVCpu->hm.s.vmx.fWasInRealMode)
                 {
-                    /** @todo If guest is in V86 mode, these checks should be different! */
-                    if ((pCtx->cs.Sel & X86_SEL_RPL) != (pCtx->ss.Sel & X86_SEL_RPL))
+                    if (!CPUMIsGuestInV86ModeEx(pCtx))
                     {
-                        STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxCheckBadRpl);
-                        return false;
+                        /* The guest switched to protected mode, check if the state is suitable for VT-x. */
+                        if ((pCtx->cs.Sel & X86_SEL_RPL) != (pCtx->ss.Sel & X86_SEL_RPL))
+                        {
+                            STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxCheckBadRpl);
+                            return false;
+                        }
+                        if (   !hmVmxIsCodeSelectorOk(&pCtx->cs, pCtx->ss.Attr.n.u2Dpl)
+                            || !hmVmxIsDataSelectorOk(&pCtx->ds)
+                            || !hmVmxIsDataSelectorOk(&pCtx->es)
+                            || !hmVmxIsDataSelectorOk(&pCtx->fs)
+                            || !hmVmxIsDataSelectorOk(&pCtx->gs)
+                            || !hmVmxIsStackSelectorOk(&pCtx->ss))
+                        {
+                            STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxCheckBadSel);
+                            return false;
+                        }
                     }
-                    if (   !hmVmxIsCodeSelectorOk(&pCtx->cs, pCtx->ss.Attr.n.u2Dpl)
-                        || !hmVmxIsDataSelectorOk(&pCtx->ds)
-                        || !hmVmxIsDataSelectorOk(&pCtx->es)
-                        || !hmVmxIsDataSelectorOk(&pCtx->fs)
-                        || !hmVmxIsDataSelectorOk(&pCtx->gs)
-                        || !hmVmxIsStackSelectorOk(&pCtx->ss))
+                    else
                     {
-                        STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxCheckBadSel);
-                        return false;
+                        /* The guest switched to V86 mode, check if the state is suitable for VT-x. */
+                        if (   pCtx->cs.Sel != (pCtx->cs.u64Base >> 4)
+                            || pCtx->ds.Sel != (pCtx->ds.u64Base >> 4)
+                            || pCtx->es.Sel != (pCtx->es.u64Base >> 4)
+                            || pCtx->ss.Sel != (pCtx->ss.u64Base >> 4)
+                            || pCtx->fs.Sel != (pCtx->fs.u64Base >> 4)
+                            || pCtx->gs.Sel != (pCtx->gs.u64Base >> 4))
+                        {
+                            STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxCheckBadV86SelBase);
+                            return false;
+                        }
+                        if (   (pCtx->cs.u32Limit != 0xffff)
+                            || (pCtx->ds.u32Limit != 0xffff)
+                            || (pCtx->es.u32Limit != 0xffff)
+                            || (pCtx->ss.u32Limit != 0xffff)
+                            || (pCtx->fs.u32Limit != 0xffff)
+                            || (pCtx->gs.u32Limit != 0xffff))
+                        {
+                            STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxCheckBadV86SelLimit);
+                            return false;
+                        }
+                        if (   (pCtx->cs.Attr.u != 0xf3)
+                            || (pCtx->ds.Attr.u != 0xf3)
+                            || (pCtx->es.Attr.u != 0xf3)
+                            || (pCtx->ss.Attr.u != 0xf3)
+                            || (pCtx->fs.Attr.u != 0xf3)
+                            || (pCtx->gs.Attr.u != 0xf3))
+                        {
+                            STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxCheckBadV86SelAttr);
+                            return false;
+                        }
                     }
                 }
@@ -738 +775 @@
         else
         {
-            if (   !CPUMIsGuestInLongModeEx(pCtx)
-                && !pVM->hm.s.vmx.fUnrestrictedGuest)
+            if (!CPUMIsGuestInLongModeEx(pCtx))
             {
                 if (   !pVM->hm.s.fNestedPaging        /* Requires a fake PD for real *and* protected mode without paging - stored in the VMM device heap */

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

@@ -823 +823 @@
         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.StatVmxCheckBadRmSelAttr,   "/HM/CPU%d/VMXCheck/RMSelAttrs", "Could not use VMX due to unsuitable real-mode selector attributes.");
+
+        HM_REG_COUNTER(&pVCpu->hm.s.StatVmxCheckBadV86SelBase,  "/HM/CPU%d/VMXCheck/V86SelBase",  "Could not use VMX due to unsuitable v8086-mode selector base.");
+        HM_REG_COUNTER(&pVCpu->hm.s.StatVmxCheckBadV86SelLimit, "/HM/CPU%d/VMXCheck/V86SelLimit", "Could not use VMX due to unsuitable v8086-mode selector limit.");
+        HM_REG_COUNTER(&pVCpu->hm.s.StatVmxCheckBadV86SelAttr,  "/HM/CPU%d/VMXCheck/V86SelAttrs", "Could not use VMX due to unsuitable v8086-mode selector attributes.");
+
         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

@@ -1068 +1068 @@
     STAMCOUNTER             StatVmxCheckBadRmSelLimit;
     STAMCOUNTER             StatVmxCheckBadRmSelAttr;
+    STAMCOUNTER             StatVmxCheckBadV86SelBase;
+    STAMCOUNTER             StatVmxCheckBadV86SelLimit;
+    STAMCOUNTER             StatVmxCheckBadV86SelAttr;
     STAMCOUNTER             StatVmxCheckRmOk;
     STAMCOUNTER             StatVmxCheckBadSel;