Changeset 84086 in vbox for trunk/src/VBox/Devices/Bus/DevIommuAmd.cpp

Timestamp:

Apr 29, 2020 3:20:29 PM (5 years ago)

Author:

vboxsync

Message:

AMD IOMMU: bugref:9654 Bits.

File:

• trunk/src/VBox/Devices/Bus/DevIommuAmd.cpp (modified) (3 diffs)

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

@@ -1851 +1851 @@
 } IOMMU_STATUS_T;
 AssertCompileSize(IOMMU_STATUS_T, 8);
+#define IOMMU_STATUS_VALID_MASK     UINT64_C(0x0000000000079fff)
+#define IOMMU_STATUS_RW1C_MASK      UINT64_C(0x0000000000068e67)
 
 /**
@@ -2729 +2731 @@
 
 
+/**
+ * Writes the Status Register (64-bit).
+ */
+static VBOXSTRICTRC iommuAmdStatus_w(PPDMDEVINS pDevIns, PIOMMU pThis, uint32_t iReg, uint64_t u64Value)
+{
+    RT_NOREF(pDevIns, iReg);
+
+    /* Mask out all unrecognized bits. */
+    u64Value &= IOMMU_STATUS_VALID_MASK;
+
+    /*
+     * Compute RW1C (read-only, write-1-to-clear) bits and preserve the rest (which are read-only).
+     * Writing 0 to an RW1C bit has no effect. Writing 1 to an RW1C bit, clears the bit if it's already 1.
+     */
+    IOMMU_STATUS_T const OldStatus = iommuAmdGetStatus(pThis);
+    uint64_t const fOldRw1cBits = (OldStatus.u64 &  IOMMU_STATUS_RW1C_MASK);
+    uint64_t const fOldRoBits   = (OldStatus.u64 & ~IOMMU_STATUS_RW1C_MASK);
+    uint64_t const fNewRw1cBits = (u64Value      &  IOMMU_STATUS_RW1C_MASK);
+
+    uint64_t const uNewStatus = (fOldRw1cBits & ~fNewRw1cBits) | fOldRoBits;
+
+    /* Update the register. */
+    ASMAtomicWriteU64(&pThis->Status.u64, uNewStatus);
+    return VINF_SUCCESS;
+}
+
+
 #if 0
 /**
@@ -2843 +2872 @@
         case IOMMU_MMIO_EVT_LOG_TAIL_PTR:        return iommuAmdEvtLogTailPtr_w(pDevIns, pThis, off, uValue);
 
-        case IOMMU_MMIO_OFF_STATUS:
+        case IOMMU_MMIO_OFF_STATUS:              return iommuAmdStatus_w(pDevIns, pThis, off, uValue);
 
         case IOMMU_MMIO_OFF_PPR_LOG_HEAD_PTR: