Changeset 74608 in vbox for trunk

Timestamp:

Oct 4, 2018 10:56:05 AM (6 years ago)

Author:

vboxsync

Message:

VMM/IEM: Nested VMX: bugref:9180 Added CR0 guest/host and read-shadow masking for Mov-from-CR0 instructions.

Location:

trunk/src/VBox/VMM/VMMAll

Files:

• IEMAllCImpl.cpp.h (modified) (1 diff)
• IEMAllCImplVmxInstr.cpp.h (modified) (1 diff)

trunk/src/VBox/VMM/VMMAll/IEMAllCImpl.cpp.h

@@ -5208 +5208 @@
         IEM_NOT_REACHED_DEFAULT_CASE_RET(); /* call checks */
     }
+
+#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
+    if (IEM_VMX_IS_NON_ROOT_MODE(pVCpu))
+    {
+        if (iCrReg == 0)
+            crX = iemVmxGetMaskedCr0(pVCpu, crX);
+    }
+#endif
 
     /* store it */

trunk/src/VBox/VMM/VMMAll/IEMAllCImplVmxInstr.cpp.h

@@ -901 +901 @@
 
 /**
+ * Gets the nested-guest CR0 mask subjected to the CR0 guest/host mask and the CR0
+ * read-shadow.
+ *
+ * @returns The masked CR0.
+ * @param   pVCpu       The cross context virtual CPU structure.
+ * @param   uGuestCr0   The guest CR0.
+ */
+IEM_STATIC uint64_t iemVmxGetMaskedCr0(PVMCPU pVCpu, uint64_t uGuestCr0)
+{
+    PCVMXVVMCS pVmcs = pVCpu->cpum.GstCtx.hwvirt.vmx.CTX_SUFF(pVmcs);
+    Assert(pVmcs);
+    Assert(IEM_VMX_IS_NON_ROOT_MODE(pVCpu));
+
+    /*
+     * For each CR0 bit owned by the host, the corresponding bit is loaded from the
+     * CR0-read shadow. For each CR0 bit that is not owned by the host, the corresponding
+     * bit from the guest CR0 is loaded.
+     *
+     * See Intel Spec. 25.3 "Changes To Instruction Behavior In VMX Non-root Operation".
+     */
+    uint64_t const fGstHostMask = pVmcs->u64Cr0Mask.u;
+    uint64_t const fReadShadow  = pVmcs->u64Cr0ReadShadow.u;
+    uint64_t const fMaskedCr0   = (fReadShadow & fGstHostMask) | (uGuestCr0 & ~fGstHostMask);
+
+    return fMaskedCr0;
+}
+
+
+/**
  * Gets VM-exit instruction information along with any displacement for an
  * instruction VM-exit.