Changeset 84242 in vbox for trunk/src/VBox/Devices/Bus/DevIommuAmd.cpp

Timestamp:

May 11, 2020 9:13:23 AM (5 years ago)

Author:

vboxsync

Message:

AMD IOMMU: bugref:9654 Use a separate IOWALKRESULT struct rather than use IOTLBE as I expect to change IOTLBE soon (e.g., if it's all 4K pages, we might not need to store 'cShift' in it)

File:

• trunk/src/VBox/Devices/Bus/DevIommuAmd.cpp (modified) (17 diffs)

trunk/src/VBox/Devices/Bus/DevIommuAmd.cpp

@@ -2203 +2203 @@
 
 /**
+ * I/O page walk result.
+ */
+typedef struct
+{
+    /** The translated system physical address. */
+    RTGCPHYS        GCPhysSpa;
+    /** The number of offset bits in the system physical address. */
+    uint8_t         cShift;
+    /** The I/O permissions allowed by the translation (IOMMU_IO_PERM_XXX). */
+    uint8_t         fIoPerm;
+    /** Padding. */
+    uint8_t         abPadding[2];
+} IOWALKRESULT;
+/** Pointer to an I/O walk result struct. */
+typedef IOWALKRESULT *PIOWALKRESULT;
+/** Pointer to a const I/O walk result struct. */
+typedef IOWALKRESULT *PCIOWALKRESULT;
+
+/**
  * IOMMU I/O TLB Entry.
  * @note Update iommuAmdInitIotlbe() when changes are made.
@@ -3605 +3624 @@
     pEvtDevTabHwErr->n.u16DevId      = uDevId;
     pEvtDevTabHwErr->n.u1Intr        = RT_BOOL(enmOp == IOMMUOP_INTR_REQ);
-    /** @todo r=ramshankar: Any other transaction type that can set read/write bit? */
+    /** @todo IOMMU: Any other transaction type that can set read/write bit? */
     pEvtDevTabHwErr->n.u1ReadWrite   = RT_BOOL(enmOp == IOMMUOP_MEM_WRITE);
     pEvtDevTabHwErr->n.u1Translation = RT_BOOL(enmOp == IOMMUOP_TRANSLATE_REQ);
@@ -3959 +3978 @@
 
 /**
- * Walks the I/O page table(s) to translate the I/O virtual address to a system
+ * Walks the I/O page table to translate the I/O virtual address to a system
  * physical address.
  *
  * @returns VBox status code.
- * @param   pDevIns     The IOMMU device instance.
- * @param   uIova       The I/O virtual address to translate. Must be 4K aligned!
- * @param   uDevId      The device ID.
- * @param   fAccess     The access permissions (IOMMU_IO_PERM_XXX). This is the
- *                      permissions for the access being made.
- * @param   pDte        The device table entry.
- * @param   enmOp       The IOMMU operation being performed.
- * @param   pIotlbe     The IOTLB entry to update with the results of the
- *                      translation.
+ * @param   pDevIns         The IOMMU device instance.
+ * @param   uIova           The I/O virtual address to translate. Must be 4K aligned.
+ * @param   uDevId          The device ID.
+ * @param   fAccess         The access permissions (IOMMU_IO_PERM_XXX). This is the
+ *                          permissions for the access being made.
+ * @param   pDte            The device table entry.
+ * @param   enmOp           The IOMMU operation being performed.
+ * @param   pWalkResult     Where to store the results of the I/O page walk. This is
+ *                          only updated when VINF_SUCCESS is returned.
  *
  * @thread  Any.
  */
-static int iommuAmdWalkIoPageTables(PPDMDEVINS pDevIns, uint16_t uDevId, uint64_t uIova, uint8_t fAccess, PCDTE_T pDte,
-                                    IOMMUOP enmOp, PIOTLBE_T pIotlbe)
+static int iommuAmdWalkIoPageTable(PPDMDEVINS pDevIns, uint16_t uDevId, uint64_t uIova, uint8_t fAccess, PCDTE_T pDte,
+                                   IOMMUOP enmOp, PIOWALKRESULT pWalkResult)
 {
     Assert(pDte->n.u1Valid);
-    /* The input I/O virtual address must be 4K page aligned. */
     Assert(!(uIova & X86_PAGE_4K_OFFSET_MASK));
 
@@ -4002 +4020 @@
     /* If the root page table level is 0, translation is skipped and access is controlled by the permission bits. */
     uint8_t const uMaxLevel = pDte->n.u3Mode;
-    if (uMaxLevel == 0)
+    if (uMaxLevel != 0)
+    { /* likely */ }
+    else
     {
         uint8_t const fDtePerm = (pDte->au64[0] >> IOMMU_IO_PERM_SHIFT) & IOMMU_IO_PERM_MASK;
@@ -4010 +4030 @@
             return VERR_IOMMU_ADDR_ACCESS_DENIED;
         }
-        iommuAmdUpdateIotlbe(uIova, 0 /* cShift */, fDtePerm, pIotlbe);
+        pWalkResult->GCPhysSpa = uIova;
+        pWalkResult->cShift    = 0;
+        pWalkResult->fIoPerm   = fDtePerm;
         return VINF_SUCCESS;
     }
 
     /* If the root page table level exceeds the allowed host-address translation level, page walk is terminated. */
-    if (uMaxLevel > IOMMU_MAX_HOST_PT_LEVEL)
+    if (uMaxLevel <= IOMMU_MAX_HOST_PT_LEVEL)
+    { /* likely */ }
+    else
     {
         /** @todo r=ramshankar: I cannot make out from the AMD IOMMU spec. if I should be
@@ -4030 +4054 @@
     /* Check permissions bits of the root page table. */
     uint8_t const fPtePerm  = (pDte->au64[0] >> IOMMU_IO_PERM_SHIFT) & IOMMU_IO_PERM_MASK;
-    if ((fAccess & fPtePerm) != fAccess)
+    if ((fAccess & fPtePerm) == fAccess)
+    { /* likely */ }
+    else
     {
         EVT_IO_PAGE_FAULT_T EvtIoPageFault;
@@ -4039 +4065 @@
     }
 
-    /** @todo IOMMU: Split the rest of this into a separate function called
-     *        iommuAmdWalkIoPageDirectory() and call it for multi-page accesses. We can
-     *        avoid re-checking the DTE root-page table entry every time. */
+    /** @todo r=ramshankar: IOMMU: Consider splitting the rest of this into a separate
+     *        function called iommuAmdWalkIoPageDirectory() and call it for multi-page
+     *        accesses from the 2nd page. We can avoid re-checking the DTE root-page
+     *        table entry every time. Not sure if it's worth optimizing that case now
+     *        or if at all. */
 
     /* The virtual address bits indexing table. */
@@ -4112 +4140 @@
         {
             /* The page size of the translation is the default (4K). */
-            pIotlbe->GCPhysSpa = PtEntity.u64 & IOMMU_PTENTITY_ADDR_MASK;
-            pIotlbe->cShift    = X86_PAGE_4K_SHIFT;
-            pIotlbe->fIoPerm   = fPtePerm;
+            pWalkResult->GCPhysSpa = PtEntity.u64 & IOMMU_PTENTITY_ADDR_MASK;
+            pWalkResult->cShift    = X86_PAGE_4K_SHIFT;
+            pWalkResult->fIoPerm   = fPtePerm;
             return VINF_SUCCESS;
         }
@@ -4130 +4158 @@
                 && cShift < s_acIovaLevelShifts[uLevel + 1])
             {
-                pIotlbe->GCPhysSpa = GCPhysPte;
-                pIotlbe->cShift    = cShift;
-                pIotlbe->fIoPerm   = fPtePerm;
+                pWalkResult->GCPhysSpa = GCPhysPte;
+                pWalkResult->cShift    = cShift;
+                pWalkResult->fIoPerm   = fPtePerm;
                 return VINF_SUCCESS;
             }
@@ -4200 +4228 @@
 
 /**
- * Looks up an I/O virtual address from the device table(s).
+ * Looks up an I/O virtual address from the device table.
  *
  * @returns VBox status code.
@@ -4216 +4244 @@
  * @thread  Any.
  */
-static int iommuAmdLookupDeviceTables(PPDMDEVINS pDevIns, uint16_t uDevId, uint64_t uIova, size_t cbAccess, uint8_t fAccess,
-                                      IOMMUOP enmOp, PRTGCPHYS pGCPhysSpa)
+static int iommuAmdLookupDeviceTable(PPDMDEVINS pDevIns, uint16_t uDevId, uint64_t uIova, size_t cbAccess, uint8_t fAccess,
+                                     IOMMUOP enmOp, PRTGCPHYS pGCPhysSpa)
 {
     PIOMMU pThis = PDMDEVINS_2_DATA(pDevIns, PIOMMU);
@@ -4231 +4259 @@
         else
         {
+            /** @todo IOMMU: Add to IOLTB cache. */
             *pGCPhysSpa = uIova;
             return VINF_SUCCESS;
@@ -4256 +4285 @@
         else
         {
+            /** @todo IOMMU: Add to IOLTB cache. */
             *pGCPhysSpa = uIova;
             return VINF_SUCCESS;
@@ -4262 +4292 @@
         /** @todo IOMMU: Perhaps do the <= 4K access case first, if the generic loop
          *        below gets too expensive and when we have iommuAmdWalkIoPageDirectory. */
-
-        IOTLBE_T Iotlbe;
-        iommuAmdInitIotlbe(NIL_RTGCPHYS, 0 /* cShift */, IOMMU_IO_PERM_NONE, &Iotlbe);
 
         uint64_t uBaseIova   = uIova & X86_PAGE_4K_BASE_MASK;
@@ -4272 +4299 @@
         {
             /* Walk the I/O page tables to translate the IOVA and check permission for the access. */
-            rc = iommuAmdWalkIoPageTables(pDevIns, uDevId, uBaseIova, fAccess, &Dte, enmOp, &Iotlbe);
+            IOWALKRESULT WalkResult;
+            rc = iommuAmdWalkIoPageTable(pDevIns, uDevId, uBaseIova, fAccess, &Dte, enmOp, &WalkResult);
             if (RT_SUCCESS(rc))
             {
+                /** @todo IOMMU: Split large pages into 4K IOTLB entries and add to IOTLB cache. */
+
                 /* Store the translated base address before continuing to check permissions for any more pages. */
                 if (cbRemaining == cbAccess)
                 {
-                    RTGCPHYS const offSpa = ~(UINT64_C(0xffffffffffffffff) << Iotlbe.cShift);
-                    *pGCPhysSpa = Iotlbe.GCPhysSpa | offSpa;
+                    RTGCPHYS const offSpa = ~(UINT64_C(0xffffffffffffffff) << WalkResult.cShift);
+                    *pGCPhysSpa = WalkResult.GCPhysSpa | offSpa;
                 }
 
-                /** @todo IOMMU: Split large pages into 4K IOTLB entries and add to IOTLB cache. */
-
-                uint64_t const cbPhysPage = UINT64_C(1) << Iotlbe.cShift;
+                uint64_t const cbPhysPage = UINT64_C(1) << WalkResult.cShift;
                 if (cbRemaining > cbPhysPage - offIova)
                 {
@@ -4337 +4365 @@
         /** @todo IOMMU: IOTLB cache lookup. */
 
-        /* Lookup the IOVA from the device tables. */
-        return iommuAmdLookupDeviceTables(pDevIns, uDevId, uIova, cbRead, IOMMU_IO_PERM_READ, IOMMUOP_MEM_READ, pGCPhysSpa);
+        /* Lookup the IOVA from the device table. */
+        return iommuAmdLookupDeviceTable(pDevIns, uDevId, uIova, cbRead, IOMMU_IO_PERM_READ, IOMMUOP_MEM_READ, pGCPhysSpa);
     }
 
@@ -4360 +4388 @@
 static int iommuAmdDeviceMemWrite(PPDMDEVINS pDevIns, uint16_t uDevId, uint64_t uIova, size_t cbWrite, PRTGCPHYS pGCPhysSpa)
 {
-    RT_NOREF(pDevIns, uDevId, uIova, cbWrite, pGCPhysSpa);
-    return VERR_NOT_IMPLEMENTED;
+    Assert(pDevIns);
+    Assert(pGCPhysSpa);
+    Assert(cbWrite > 0);
+
+    PIOMMU pThis = PDMDEVINS_2_DATA(pDevIns, PIOMMU);
+
+    /* Addresses are forwarded without translation when the IOMMU is disabled. */
+    IOMMU_CTRL_T const Ctrl = iommuAmdGetCtrl(pThis);
+    if (Ctrl.n.u1IommuEn)
+    {
+        /** @todo IOMMU: IOTLB cache lookup. */
+
+        /* Lookup the IOVA from the device table. */
+        return iommuAmdLookupDeviceTable(pDevIns, uDevId, uIova, cbWrite, IOMMU_IO_PERM_WRITE, IOMMUOP_MEM_WRITE, pGCPhysSpa);
+    }
+
+    *pGCPhysSpa = uIova;
+    return VINF_SUCCESS;
 }