Changeset 50540 in vbox for trunk/src/VBox/HostDrivers/Support

Timestamp:

Feb 21, 2014 12:51:57 PM (11 years ago)

Author:

vboxsync

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

92390

Message:

VMM/HM: Ignore SMX mode and proceed with a warning.

File:

• trunk/src/VBox/HostDrivers/Support/SUPDrv.c (modified) (7 diffs)

trunk/src/VBox/HostDrivers/Support/SUPDrv.c

@@ -3394 +3394 @@
  * @returns VBox status code.
  * @retval  VERR_VMX_NO_VMX
- * @retval  VERR_VMX_MSR_SMX_VMXON_DISABLED
+ * @retval  VERR_VMX_MSR_ALL_VMXON_DISABLED
  * @retval  VERR_VMX_MSR_VMXON_DISABLED
  * @retval  VERR_VMX_MSR_LOCKING_FAILED
@@ -3407 +3407 @@
 SUPR0DECL(int) SUPR0QueryVTCaps(PSUPDRVSESSION pSession, uint32_t *pfCaps)
 {
-    int rc = VERR_UNSUPPORTED_CPU;
+    int  rc = VERR_UNSUPPORTED_CPU;
+    bool fIsSmxModeAmbiguous = false;
     RTTHREADPREEMPTSTATE PreemptState = RTTHREADPREEMPTSTATE_INITIALIZER;
 
@@ -3439 +3440 @@
                 /** @todo Unify code with hmR0InitIntelCpu(). */
                 uint64_t   u64FeatMsr     = ASMRdMsr(MSR_IA32_FEATURE_CONTROL);
-                bool const fInSmxMode     = RT_BOOL(ASMGetCR4() & X86_CR4_SMXE);
+                bool const fMaybeSmxMode  = RT_BOOL(ASMGetCR4() & X86_CR4_SMXE);
                 bool       fMsrLocked     = RT_BOOL(u64FeatMsr & MSR_IA32_FEATURE_CONTROL_LOCK);
                 bool       fSmxVmxAllowed = RT_BOOL(u64FeatMsr & MSR_IA32_FEATURE_CONTROL_SMX_VMXON);
@@ -3447 +3448 @@
                 if (fMsrLocked)
                 {
-                    if (fInSmxMode && !fSmxVmxAllowed)
-                        rc = VERR_VMX_MSR_SMX_VMXON_DISABLED;
-                    else if (!fInSmxMode && !fVmxAllowed)
-                        rc = VERR_VMX_MSR_VMXON_DISABLED;
+                    if (fVmxAllowed && fSmxVmxAllowed)
+                        rc = VINF_SUCCESS;
+                    else if (!fVmxAllowed && !fSmxVmxAllowed)
+                        rc = VERR_VMX_MSR_ALL_VMXON_DISABLED;
+                    else if (!fMaybeSmxMode)
+                    {
+                        if (fVmxAllowed)
+                            rc = VINF_SUCCESS;
+                        else
+                            rc = VERR_VMX_MSR_VMXON_DISABLED;
+                    }
                     else
+                    {
+                        /*
+                         * CR4.SMXE is set but this doesn't mean the CPU is necessarily in SMX mode. We shall assume
+                         * that it is -not- and that it is a stupid BIOS/OS setting CR4.SMXE for no good reason.
+                         * See @bugref{6873}.
+                         */
+                        Assert(fMaybeSmxMode == true);
+                        fIsSmxModeAmbiguous = true;
                         rc = VINF_SUCCESS;
+                    }
                 }
                 else
@@ -3459 +3476 @@
                      * MSR is not yet locked; we can change it ourselves here.
                      * Once the lock bit is set, this MSR can no longer be modified.
+                     *
+                     * Set both the VMXON and SMX_VMXON bits as we can't determine SMX mode
+                     * accurately. See @bugref{6873}.
                      */
-                    bool fAllowed;
-                    u64FeatMsr |= MSR_IA32_FEATURE_CONTROL_LOCK;
-                    if (fInSmxMode)
-                        u64FeatMsr |= MSR_IA32_FEATURE_CONTROL_SMX_VMXON;
-                    else
-                        u64FeatMsr |= MSR_IA32_FEATURE_CONTROL_VMXON;
-
+                    u64FeatMsr |=   MSR_IA32_FEATURE_CONTROL_LOCK
+                                  | MSR_IA32_FEATURE_CONTROL_SMX_VMXON
+                                  | MSR_IA32_FEATURE_CONTROL_VMXON;
                     ASMWrMsr(MSR_IA32_FEATURE_CONTROL, u64FeatMsr);
 
@@ -3474 +3490 @@
                     fSmxVmxAllowed = fMsrLocked && RT_BOOL(u64FeatMsr & MSR_IA32_FEATURE_CONTROL_SMX_VMXON);
                     fVmxAllowed    = fMsrLocked && RT_BOOL(u64FeatMsr & MSR_IA32_FEATURE_CONTROL_VMXON);
-                    fAllowed       = fInSmxMode ? fSmxVmxAllowed : fVmxAllowed;
-                    if (fAllowed)
+                    if (fSmxVmxAllowed && fVmxAllowed)
                         rc = VINF_SUCCESS;
                     else
@@ -3535 +3550 @@
 
     RTThreadPreemptRestore(&PreemptState);
+    if (fIsSmxModeAmbiguous)
+        SUPR0Printf(("Warning!!! CR4 hints SMX mode but your CPU is too secretive. Proceeding anyway... Wish us luck!\n"));
     return rc;
 }