Changeset 92642 in vbox for trunk/src/VBox

Timestamp:

Nov 30, 2021 9:19:01 AM (3 years ago)

Author:

vboxsync

Message:

VMM: Nested VMX: bugref:10092 Avoid RT_ZERO'ing multiple times, also just use passed in pWalk rather than construct another copy on the stack. Assert basic assumptions when Walk succeeds.

Location:

trunk/src/VBox/VMM/VMMAll

Files:

• PGMAll.cpp (modified) (1 diff)
• PGMAllGst.h (modified) (2 diffs)

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

@@ -1733 +1733 @@
     VMCPU_ASSERT_EMT(pVCpu);
     Assert(pWalk);
-    RT_BZERO(pWalk, sizeof(*pWalk));
     uintptr_t idx = pVCpu->pgm.s.idxGuestModeData;
     AssertReturn(idx < RT_ELEMENTS(g_aPgmGuestModeData), VERR_PGM_MODE_IPE);

trunk/src/VBox/VMM/VMMAll/PGMAllGst.h

@@ -380 +380 @@
    || PGM_GST_TYPE == PGM_TYPE_AMD64
 
-    PGMPTWALK Walk;
     GSTPTWALK GstWalk;
-    RT_ZERO(Walk);
-    RT_ZERO(GstWalk);
-    int rc = PGM_GST_NAME(Walk)(pVCpu, GCPtr, &Walk, &GstWalk);
+    int rc = PGM_GST_NAME(Walk)(pVCpu, GCPtr, pWalk, &GstWalk);
     if (RT_FAILURE(rc))
         return rc;
 
-    uint64_t fFlags;
-    if (!Walk.fBigPage)
+    Assert(pWalk->fSucceeded);
+    Assert(pWalk->GCPtr == GCPtr);
+
+    PGMPTATTRS fFlags;
+    if (!pWalk->fBigPage)
         fFlags = (GstWalk.Pte.u & ~(GST_PTE_PG_MASK | X86_PTE_RW | X86_PTE_US))                      /* NX not needed */
-               | (Walk.fEffective & (PGM_PTATTRS_W_MASK | PGM_PTATTRS_US_MASK))
+               | (pWalk->fEffective & (PGM_PTATTRS_W_MASK | PGM_PTATTRS_US_MASK))
 # if PGM_WITH_NX(PGM_GST_TYPE, PGM_GST_TYPE)
-               | (Walk.fEffective & PGM_PTATTRS_NX_MASK)
+               | (pWalk->fEffective & PGM_PTATTRS_NX_MASK)
 # endif
                  ;
@@ -399 +399 @@
     {
         fFlags = (GstWalk.Pde.u & ~(GST_PTE_PG_MASK | X86_PDE4M_RW | X86_PDE4M_US | X86_PDE4M_PS))   /* NX not needed */
-               | (Walk.fEffective & (PGM_PTATTRS_W_MASK | PGM_PTATTRS_US_MASK | PGM_PTATTRS_PAT_MASK))
+               | (pWalk->fEffective & (PGM_PTATTRS_W_MASK | PGM_PTATTRS_US_MASK | PGM_PTATTRS_PAT_MASK))
 # if PGM_WITH_NX(PGM_GST_TYPE, PGM_GST_TYPE)
-               | (Walk.fEffective & PGM_PTATTRS_NX_MASK)
+               | (pWalk->fEffective & PGM_PTATTRS_NX_MASK)
 # endif
                ;
     }
 
-    pWalk->fSucceeded = true;
-    pWalk->GCPtr      = GCPtr;
-    pWalk->GCPhys     = Walk.GCPhys & ~(RTGCPHYS)PAGE_OFFSET_MASK;
+    pWalk->GCPhys    &= ~(RTGCPHYS)PAGE_OFFSET_MASK;
     pWalk->fEffective = fFlags;
     return VINF_SUCCESS;