Changeset 13048 in vbox for trunk/src/VBox/VMM

Timestamp:

Oct 7, 2008 1:33:00 PM (16 years ago)

Author:

vboxsync

Message:

Real and protected mode without paging needs a special identity mapping page table in EPT mode.

Location:

trunk/src/VBox/VMM

Files:

• HWACCM.cpp (modified) (2 diffs)
• HWACCMInternal.h (modified) (2 diffs)
• VMMR0/HWVMXR0.cpp (modified) (2 diffs)

trunk/src/VBox/VMM/HWACCM.cpp

@@ -530 +530 @@
 
             /* Allocate three pages for the TSS we need for real mode emulation. (2 page for the IO bitmap) */
-            rc = PDMR3VMMDevHeapAlloc(pVM, HWACCM_VTX_TSS_SIZE, (RTR3PTR *)&pVM->hwaccm.s.vmx.pRealModeTSS);
+            rc = PDMR3VMMDevHeapAlloc(pVM, HWACCM_VTX_TOTAL_DEVHEAP_MEM, (RTR3PTR *)&pVM->hwaccm.s.vmx.pRealModeTSS);
             AssertRC(rc);
             if (RT_FAILURE(rc))
@@ -543 +543 @@
             memset(pVM->hwaccm.s.vmx.pRealModeTSS + 1, 0, PAGE_SIZE*2);
             *((unsigned char *)pVM->hwaccm.s.vmx.pRealModeTSS + HWACCM_VTX_TSS_SIZE - 2) = 0xff;
+
+            /* Construct a 1024 element page directory with 4 MB pages for the identity mapped page table used in 
+             * real and protected mode without paging with EPT.
+             */
+            pVM->hwaccm.s.vmx.pRealModeEPTPageTable = (PX86PD)((char *)pVM->hwaccm.s.vmx.pRealModeTSS + PAGE_SIZE * 3);
+            for (unsigned i=0;i<X86_PG_ENTRIES;i++)
+            {
+                pVM->hwaccm.s.vmx.pRealModeEPTPageTable->a[i].u = X86_PDE4M_P | X86_PDE4M_RW | X86_PDE4M_US | X86_PDE4M_A | X86_PDE4M_D | X86_PDE4M_PS | X86_PDE4M_G;
+                pVM->hwaccm.s.vmx.pRealModeEPTPageTable->a[i].b.u10PageNo  = _4M * i;
+            }
 
             rc = SUPCallVMMR0Ex(pVM->pVMR0, VMMR0_DO_HWACC_SETUP_VM, 0, NULL);

trunk/src/VBox/VMM/HWACCMInternal.h

@@ -125 +125 @@
 #define HWACCM_MAX_RESUME_LOOPS             1024
 
+/** Size for the EPT identity page table (1024 4 MB pages to cover the entire address space). */
+#define HWACCM_EPT_IDENTITY_PG_TABLE_SIZE   PAGE_SIZE
 /** Size of the TSS structure + 2 pages for the IO bitmap + end byte. */
 #define HWACCM_VTX_TSS_SIZE                 (sizeof(VBOXTSS) + 2*PAGE_SIZE + 1)
+/** Total guest mapped memory needed. */
+#define HWACCM_VTX_TOTAL_DEVHEAP_MEM        (HWACCM_EPT_IDENTITY_PG_TABLE_SIZE + HWACCM_VTX_TSS_SIZE)
 
 /** HWACCM SSM version
@@ -235 +239 @@
         /** Virtual address of the TSS page used for real mode emulation. */
         R3PTRTYPE(PVBOXTSS)         pRealModeTSS;
-#if HC_ARCH_BITS == 32
-        uint32_t                    padding2; /**< explicit alignment for 32-bit gcc */
-#endif
+
+        /** Virtual address of the identity page table used for real mode emulation in EPT mode. */
+        R3PTRTYPE(PX86PD)           pRealModeEPTPageTable;
 
         /** R0 memory object for the virtual APIC mmio cache. */

trunk/src/VBox/VMM/VMMR0/HWVMXR0.cpp

@@ -1092 +1092 @@
             }
         }
+        else
+        if (!(pCtx->cr0 & X86_CR0_PG))
+        {
+            /* We use 4 MB pages in our identity mapping page table for real and protected mode without paging. */
+            val |= X86_CR4_PSE;
+        }
 
 #ifdef HWACCM_VMX_EMULATE_REALMODE
@@ -1137 +1143 @@
             AssertRC(rc);
 
-            /* Save the real guest CR3 in VMX_VMCS_GUEST_CR3 */
-            val = pCtx->cr3;
+            if (!(pCtx->cr0 & X86_CR0_PG))
+            {
+                RTGCPHYS GCPhys;
+
+                /* We convert it here every time as pci regions could be reconfigured. */
+                rc = PDMVMMDevHeapR3ToGCPhys(pVM, pVM->hwaccm.s.vmx.pRealModeEPTPageTable, &GCPhys);
+                AssertRC(rc);
+
+                /* We use our identity mapping page table here as we need to map guest virtual to guest physical addresses; EPT will
+                 * take care of the translation to host physical addresses.
+                 */
+                val = GCPhys;
+            }
+            else
+            {
+                /* Save the real guest CR3 in VMX_VMCS_GUEST_CR3 */
+                val = pCtx->cr3;
+            }
         }
         /* Save our shadow CR3 register. */