Changeset 84505 in vbox for trunk/src

Timestamp:

May 25, 2020 2:53:12 PM (5 years ago)

Author:

vboxsync

Message:

IEM: Adding iemMemFetchDataU32_ZX_U64 to deal with techically correct warning about using an uninitialized variable in vmx_write. bugref:9746

Location:

trunk/src/VBox/VMM/VMMAll

Files:

• IEMAll.cpp (modified) (2 diffs)
• IEMAllCImplVmxInstr.cpp.h (modified) (1 diff)

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

@@ -956 +956 @@
 IEM_STATIC VBOXSTRICTRC     iemMemCommitAndUnmap(PVMCPUCC pVCpu, void *pvMem, uint32_t fAccess);
 IEM_STATIC VBOXSTRICTRC     iemMemFetchDataU32(PVMCPUCC pVCpu, uint32_t *pu32Dst, uint8_t iSegReg, RTGCPTR GCPtrMem);
+IEM_STATIC VBOXSTRICTRC     iemMemFetchDataU32_ZX_U64(PVMCPUCC pVCpu, uint64_t *pu64Dst, uint8_t iSegReg, RTGCPTR GCPtrMem);
 IEM_STATIC VBOXSTRICTRC     iemMemFetchDataU64(PVMCPUCC pVCpu, uint64_t *pu64Dst, uint8_t iSegReg, RTGCPTR GCPtrMem);
 IEM_STATIC VBOXSTRICTRC     iemMemFetchSysU8(PVMCPUCC pVCpu, uint32_t *pu32Dst, uint8_t iSegReg, RTGCPTR GCPtrMem);
@@ -9160 +9161 @@
 
 
+/**
+ * Fetches a data dword and zero extends it to a qword.
+ *
+ * @returns Strict VBox status code.
+ * @param   pVCpu               The cross context virtual CPU structure of the calling thread.
+ * @param   pu64Dst             Where to return the qword.
+ * @param   iSegReg             The index of the segment register to use for
+ *                              this access.  The base and limits are checked.
+ * @param   GCPtrMem            The address of the guest memory.
+ */
+IEM_STATIC VBOXSTRICTRC iemMemFetchDataU32_ZX_U64(PVMCPUCC pVCpu, uint64_t *pu64Dst, uint8_t iSegReg, RTGCPTR GCPtrMem)
+{
+    /* The lazy approach for now... */
+    uint32_t const *pu32Src;
+    VBOXSTRICTRC rc = iemMemMap(pVCpu, (void **)&pu32Src, sizeof(*pu32Src), iSegReg, GCPtrMem, IEM_ACCESS_DATA_R);
+    if (rc == VINF_SUCCESS)
+    {
+        *pu64Dst = *pu32Src;
+        rc = iemMemCommitAndUnmap(pVCpu, (void *)pu32Src, IEM_ACCESS_DATA_R);
+    }
+    return rc;
+}
+
+
 #ifdef IEM_WITH_SETJMP
 

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

@@ -7908 +7908 @@
             rcStrict = iemMemFetchDataU64(pVCpu, &u64Val, iEffSeg, GCPtrVal);
         else
-        {
-            uint32_t u32Val;
-            rcStrict = iemMemFetchDataU32(pVCpu, &u32Val, iEffSeg, GCPtrVal);
-            u64Val = u32Val;
-        }
+            rcStrict = iemMemFetchDataU32_ZX_U64(pVCpu, &u64Val, iEffSeg, GCPtrVal);
         if (RT_UNLIKELY(rcStrict != VINF_SUCCESS))
         {