Changeset 97231 in vbox for trunk/src/VBox/VMM/VMMR3

Timestamp:

Oct 19, 2022 9:12:57 AM (2 years ago)

Author:

vboxsync

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

154207

Message:

VMM/CPUM: Define our own X86EFLAGS/X86RFLAGS structures so we can use reserved bits for internal state.

Location:

trunk/src/VBox/VMM/VMMR3

Files:

• CPUM.cpp (modified) (6 diffs)
• EM.cpp (modified) (1 diff)

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

@@ -145 +145 @@
 #include <iprt/mem.h>
 #include <iprt/mp.h>
+#include <iprt/rand.h>
 #include <iprt/string.h>
 
@@ -2205 +2206 @@
 
     /*
+     * Generate the RFLAGS cookie.
+     */
+    pVM->cpum.s.fReservedRFlagsCookie = RTRandU64() & ~(CPUMX86EFLAGS_HW_MASK_64 | CPUMX86EFLAGS_INT_MASK_64);
+
+    /*
      * Init the VMX/SVM state.
      *
@@ -2220 +2226 @@
         Assert(pVM->apCpusR3[0]->cpum.s.Guest.hwvirt.enmHwvirt == CPUMHWVIRT_NONE);
 
+    /*
+     * Initialize the general guest CPU state.
+     */
     CPUMR3Reset(pVM);
+
     return VINF_SUCCESS;
 }
@@ -2303 +2313 @@
     pCtx->eip                       = 0x0000fff0;
     pCtx->edx                       = 0x00000600;   /* P6 processor */
-    pCtx->eflags.Bits.u1Reserved0   = 1;
+
+    Assert((pVM->cpum.s.fReservedRFlagsCookie & (X86_EFL_LIVE_MASK | X86_EFL_RAZ_LO_MASK | X86_EFL_RA1_MASK)) == 0);
+    pCtx->rflags.uBoth              = pVM->cpum.s.fReservedRFlagsCookie | X86_EFL_RA1_MASK;
 
     pCtx->cs.Sel                    = 0xf000;
@@ -2495 +2507 @@
     for (VMCPUID idCpu = 0; idCpu < pVM->cCpus; idCpu++)
     {
-        PVMCPU pVCpu = pVM->apCpusR3[idCpu];
-
+        PVMCPU const   pVCpu   = pVM->apCpusR3[idCpu];
+        PCPUMCTX const pGstCtx = &pVCpu->cpum.s.Guest;
+
+        /** @todo ditch this the next time we change the saved state. */
         SSMR3PutStructEx(pSSM, &DummyHyperCtx,           sizeof(DummyHyperCtx),           0, g_aCpumCtxFields, NULL);
 
-        PCPUMCTX pGstCtx = &pVCpu->cpum.s.Guest;
+        uint64_t const fSavedRFlags = pGstCtx->rflags.uBoth;
+        pGstCtx->rflags.uBoth &= CPUMX86EFLAGS_HW_MASK_64; /* Temporarily clear the non-hardware bits in RFLAGS while saving. */
         SSMR3PutStructEx(pSSM, pGstCtx,                  sizeof(*pGstCtx),                0, g_aCpumCtxFields, NULL);
+        pGstCtx->rflags.uBoth  = fSavedRFlags;
+
         SSMR3PutStructEx(pSSM, &pGstCtx->XState.x87,     sizeof(pGstCtx->XState.x87),     0, g_aCpumX87Fields, NULL);
         if (pGstCtx->fXStateMask != 0)
@@ -2922 +2939 @@
             AssertRCReturn(rc, rc);
 
+            /* Deal with the reusing of reserved RFLAGS bits. */
+            pGstCtx->rflags.uBoth |= pVM->cpum.s.fReservedRFlagsCookie;
+
             /* REM and other may have cleared must-be-one fields in DR6 and
                DR7, fix these. */

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

@@ -2210 +2210 @@
                 fFFDone = false;
 
+#ifdef VBOX_STRICT
+            CPUMAssertGuestRFlagsCookie(pVM, pVCpu);
+#endif
+
             /*
              * Now what to do?