Changeset 98355 in vbox

Timestamp:

Jan 31, 2023 9:08:28 AM (2 years ago)

Author:

vboxsync

Message:

VMM/CPUM: Nested VMX: bugref:10318 Get CR4 fixed bits from what we expose to the guest overriding what's supported by hardware.

File:

• trunk/src/VBox/VMM/VMMR3/CPUM.cpp (modified) (2 diffs)

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

@@ -1531 +1531 @@
          * CPU features and/or micro-architecture/generation. Why? Ask Intel.
          */
-        uint64_t const uHostMsr = fIsNstGstHwExecAllowed ? pHostVmxMsrs->u64Cr0Fixed1 : VMX_V_CR0_FIXED1;
-        pGuestVmxMsrs->u64Cr0Fixed1 = uHostMsr | pGuestVmxMsrs->u64Cr0Fixed0;   /* Make sure the CR0 MB1 bits are not clear. */
+        pGuestVmxMsrs->u64Cr0Fixed1 = fIsNstGstHwExecAllowed ? pHostVmxMsrs->u64Cr0Fixed1 : VMX_V_CR0_FIXED1;
+
+        /* Make sure the CR0 MB1 bits are not clear. */
+        Assert((pGuestVmxMsrs->u64Cr0Fixed1 & pGuestVmxMsrs->u64Cr0Fixed0) == pGuestVmxMsrs->u64Cr0Fixed0);
     }
 
@@ -1540 +1542 @@
     /* CR4 Fixed-1. */
     {
-        uint64_t const uHostMsr = fIsNstGstHwExecAllowed ? pHostVmxMsrs->u64Cr4Fixed1 : CPUMGetGuestCR4ValidMask(pVM);
-        pGuestVmxMsrs->u64Cr4Fixed1 = uHostMsr | pGuestVmxMsrs->u64Cr4Fixed0;   /* Make sure the CR4 MB1 bits are not clear. */
+        pGuestVmxMsrs->u64Cr4Fixed1 = CPUMGetGuestCR4ValidMask(pVM) & pHostVmxMsrs->u64Cr4Fixed1;
+
+        /* Make sure the CR4 MB1 bits are not clear. */
+        Assert((pGuestVmxMsrs->u64Cr4Fixed1 & pGuestVmxMsrs->u64Cr4Fixed0) == pGuestVmxMsrs->u64Cr4Fixed0);
+
+        /* Make sure bits that must always be set are set. */
+        Assert(pGuestVmxMsrs->u64Cr4Fixed1 & X86_CR4_PAE);
+        Assert(pGuestVmxMsrs->u64Cr4Fixed1 & X86_CR4_VMXE);
     }