diff --git a/MsvmPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf b/MsvmPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf
index 02ee5827d4..e10f9c542d 100644
--- a/MsvmPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf
+++ b/MsvmPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf
@@ -95,6 +95,7 @@
     gMsvmPkgTokenSpaceGuid.PcdHmatSize                          ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdTpmEnabled                        ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdVirtualBatteryEnabled             ## CONSUMES
+    gMsvmPkgTokenSpaceGuid.PcdVmbusEnabled                      ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdWatchdogEnabled                   ## CONSUMES
 
 [Pcd.X64]
diff --git a/MsvmPkg/AcpiPlatformDxe/Dsdt.c b/MsvmPkg/AcpiPlatformDxe/Dsdt.c
index 224537c1c6..1d62bac3ab 100644
--- a/MsvmPkg/AcpiPlatformDxe/Dsdt.c
+++ b/MsvmPkg/AcpiPlatformDxe/Dsdt.c
@@ -33,6 +33,7 @@ typedef struct _DSDT_AML_DATA
     UINT8  ProcIdleEnabled;
     UINT8  CxlMemoryEnabled;
     UINT16 NvdimmCount;
+    UINT8  VmbusEnabled;
 } DSDT_AML_DATA;
 
 typedef struct _DSDT_AML_DESCRIPTOR
@@ -138,6 +139,7 @@ Return Value:
     data->ProcIdleEnabled = PcdGetBool(PcdProcIdleEnabled);
     data->CxlMemoryEnabled = PcdGetBool(PcdCxlMemoryEnabled);
     data->NvdimmCount = PcdGet16(PcdNvdimmCount);
+    data->VmbusEnabled = PcdGetBool(PcdVmbusEnabled);
 
     DEBUG((DEBUG_VERBOSE, "--- %a: Mmio1Start               0x%lx\n", __func__, data->Mmio1Start));
     DEBUG((DEBUG_VERBOSE, "--- %a: Mmio1Length              0x%lx\n", __func__, data->Mmio1Length));
diff --git a/MsvmPkg/AcpiTables/Dsdt.asl b/MsvmPkg/AcpiTables/Dsdt.asl
index abd5c3a0ba..12a6822e50 100644
--- a/MsvmPkg/AcpiTables/Dsdt.asl
+++ b/MsvmPkg/AcpiTables/Dsdt.asl
@@ -63,6 +63,7 @@ DefinitionBlock (
         PADE,8,         // Processor Aggregator Device enabled/disabled
         CCFG,8,         // CXL memory support enabled/disabled
         NCNT,16,        // NVDIMM count
+        VCFG,8,         // VMBus enabled/disabled
     }
 
     // Supported machine sleep states =========================================
@@ -140,6 +141,7 @@ DefinitionBlock (
     {
         Name(_HID, "ACPI0004")
         Name(_UID, 0)
+
         Name(_CRS,
             ResourceTemplate()
             {
@@ -166,19 +168,27 @@ DefinitionBlock (
 
         Method(_INI, 0)
         {
-            // Update the DWORDMemory resource descriptor with the low MMIO region.
-            Store(MG2B, MIN6)
-            Store(MG2L, LEN6)
-            Store(MG2L, Local0)
-            Add(MIN6, Decrement(Local0), MAX6)
+            // Update the DWORDMemory descriptor with the low MMIO region
+            // only if the region has nonzero size.
+            If(LGreater(MG2L, 0))
+            {
+                Store(MG2B, MIN6)
+                Store(MG2L, LEN6)
+                Store(MG2L, Local0)
+                Add(MIN6, Decrement(Local0), MAX6)
+            }
 
-            // Update the QWORDMemory resource descriptor with the high MMIO region.
-            ShiftLeft (HMIB, 20, Local1)
-            ShiftLeft (HMIL, 20, Local2)
-            Store(Local1, MIN7)
-            Store(Local2, LEN7)
-            Store(Local2, Local0)
-            Add(MIN7, Decrement(Local0), MAX7)
+            // Update the QWORDMemory descriptor with the high MMIO region
+            // only if the region has nonzero size.
+            If(LGreater(HMIL, 0))
+            {
+                ShiftLeft (HMIB, 20, Local1)
+                ShiftLeft (HMIL, 20, Local2)
+                Store(Local1, MIN7)
+                Store(Local2, LEN7)
+                Store(Local2, Local0)
+                Add(MIN7, Decrement(Local0), MAX7)
+            }
         }
     }
 
@@ -306,74 +316,77 @@ DefinitionBlock (
 
     // VMBus ==================================================================
 
-    Device(\_SB.VMOD.VMBS)
+    If(LGreater(VCFG, 0))
     {
-        Name(STA, 0xF)
-        Name(_ADR, 0x00)
+        Device(\_SB.VMOD.VMBS)
+        {
+            Name(STA, 0xF)
+            Name(_ADR, 0x00)
 #if defined(_DSDT_ARM_)
-        Name(_CCA, One)
+            Name(_CCA, One)
 #endif
-        Name(_DDN, "VMBUS")
-        Name(_HID, "MSFT1000")
-        Name(_CID, "VMBus")
-        Name(_UID, 0)
-        Method(_DIS, 0) { And(STA, 0xD, STA) }
-        Method(_PS0, 0) { Or(STA, 0xF, STA) }
-        Method(_STA, 0)
-        {
-            return(STA)
-        }
-
-        // Older versions of this DSDT implemented _PS3 improperly, as:
-        //     Name(_PS3, 0)
-        // This is intentionally a do-nothing method in case any version of Windows requires _PS3 to be implemented
-
-        Method(_PS3, 0) { return(STA) }
-
-        // TODO: SPIs are not available to the guest on AARCH64, which is what
-        // PcdVmbusVector is currently defined as. Supposedly it should use a PPI,
-        // but those are strange because they're reserved for hypervisor devices.
-        //
-        // Windows doesn't boot when VmBus is given an SPI, since it's unable to
-        // allocate any since none exist in guests. Thus, leave it out on AARCH64
-        // for now.
-        //
-        // Linux may need this field if it's not hardcoded, unsure.
-        //
-        // Additionally, no Interrupt-Signaled event devices currently work either,
-        // due to SPIs not being available to guests.
-        Name(_CRS,
+            Name(_DDN, "VMBUS")
+            Name(_HID, "MSFT1000")
+            Name(_CID, "VMBus")
+            Name(_UID, 0)
+            Method(_DIS, 0) { And(STA, 0xD, STA) }
+            Method(_PS0, 0) { Or(STA, 0xF, STA) }
+            Method(_STA, 0)
+            {
+                return(STA)
+            }
 
-            // Include an interrupt resource so that Linux VMs can get IDT
-            // entries.
-            //
-            // N.B. All Windows VMs that support UEFI also support
-            // getting IDT entries via other mechanisms, so this is not
-            // necessary for Windows.
+            // Older versions of this DSDT implemented _PS3 improperly, as:
+            //     Name(_PS3, 0)
+            // This is intentionally a do-nothing method in case any version of Windows requires _PS3 to be implemented
 
-            ResourceTemplate()
-            {
+            Method(_PS3, 0) { return(STA) }
+
+            // TODO: SPIs are not available to the guest on AARCH64, which is what
+            // PcdVmbusVector is currently defined as. Supposedly it should use a PPI,
+            // but those are strange because they're reserved for hypervisor devices.
+            //
+            // Windows doesn't boot when VmBus is given an SPI, since it's unable to
+            // allocate any since none exist in guests. Thus, leave it out on AARCH64
+            // for now.
+            //
+            // Linux may need this field if it's not hardcoded, unsure.
+            //
+            // Additionally, no Interrupt-Signaled event devices currently work either,
+            // due to SPIs not being available to guests.
+            Name(_CRS,
+
+                // Include an interrupt resource so that Linux VMs can get IDT
+                // entries.
+                //
+                // N.B. All Windows VMs that support UEFI also support
+                // getting IDT entries via other mechanisms, so this is not
+                // necessary for Windows.
+
+                ResourceTemplate()
+                {
 
 #if defined(_DSDT_INTEL_)
 
-                // Older Linux kernels like RHEL/CentOS don't seem to be able to
-                // parse the new Extended Interrupt Descriptor resource type (see ACPI Section 6.4.3.6),
-                // so we instead use the old legacy IRQ description which
-                // becomes the short form of Interrupt Descriptor (ACPI Section 5.4.2.1)
-                // which only supports legacy PIC devices to describe up to 15
-                // interrupts. VMBUS is interrupt 5 on X64, so this is okay.
-                IRQ(Edge,ActiveHigh,Exclusive)
-                    {FixedPcdGet8(PcdVmbusVector)}
+                    // Older Linux kernels like RHEL/CentOS don't seem to be able to
+                    // parse the new Extended Interrupt Descriptor resource type (see ACPI Section 6.4.3.6),
+                    // so we instead use the old legacy IRQ description which
+                    // becomes the short form of Interrupt Descriptor (ACPI Section 5.4.2.1)
+                    // which only supports legacy PIC devices to describe up to 15
+                    // interrupts. VMBUS is interrupt 5 on X64, so this is okay.
+                    IRQ(Edge,ActiveHigh,Exclusive)
+                        {FixedPcdGet8(PcdVmbusVector)}
 
 #else
-                // On AArch64, we select a PPI (16) because Linux expects it to
-                // be available to all CPUs.
-                Interrupt(ResourceConsumer, Edge, ActiveHigh, Exclusive)
-                   {FixedPcdGet8(PcdVmbusVector)}
+                    // On AArch64, we select a PPI (16) because Linux expects it to
+                    // be available to all CPUs.
+                    Interrupt(ResourceConsumer, Edge, ActiveHigh, Exclusive)
+                       {FixedPcdGet8(PcdVmbusVector)}
 
 #endif
-            }
-        )
+                }
+            )
+        }
     }
 
     // TPM ====================================================================
diff --git a/MsvmPkg/Include/BiosInterface.h b/MsvmPkg/Include/BiosInterface.h
index 72e6d6f9ec..42951361b4 100644
--- a/MsvmPkg/Include/BiosInterface.h
+++ b/MsvmPkg/Include/BiosInterface.h
@@ -789,7 +789,9 @@ typedef struct _UEFI_CONFIG_FLAGS
         UINT64 Dhcp6DuidTypeLlt : 1;
         UINT64 CxlMemoryEnabled : 1;
         UINT64 MtrrsInitializedAtLoad : 1;
-        UINT64 Reserved:35;
+        UINT64 HvSintEnabled : 1;  // Reserved; used by other codebase.
+        UINT64 VmbusDisabled : 1;
+        UINT64 Reserved:33;
     } Flags;
 } UEFI_CONFIG_FLAGS;
 
diff --git a/MsvmPkg/Library/DeviceBootManagerLib/DeviceBootManagerLib.c b/MsvmPkg/Library/DeviceBootManagerLib/DeviceBootManagerLib.c
index 470c4388b5..ca787830d9 100644
--- a/MsvmPkg/Library/DeviceBootManagerLib/DeviceBootManagerLib.c
+++ b/MsvmPkg/Library/DeviceBootManagerLib/DeviceBootManagerLib.c
@@ -425,6 +425,10 @@ DeviceBootManagerBeforeConsole (
     *DevicePath = NULL;
     *PlatformConsoles = NULL;
 
+    if (!PcdGetBool(PcdVmbusEnabled)) {
+        goto Exit;
+    }
+
     Status = gBS->LocateHandleBuffer (
        ByProtocol,
        &gEfiVmbusProtocolGuid,
diff --git a/MsvmPkg/Library/DeviceBootManagerLib/DeviceBootManagerLib.inf b/MsvmPkg/Library/DeviceBootManagerLib/DeviceBootManagerLib.inf
index 40d7a5e73b..f52f9c937d 100644
--- a/MsvmPkg/Library/DeviceBootManagerLib/DeviceBootManagerLib.inf
+++ b/MsvmPkg/Library/DeviceBootManagerLib/DeviceBootManagerLib.inf
@@ -69,6 +69,7 @@ CONSTRUCTOR                    = DeviceBootManagerConstructor
   gMsvmPkgTokenSpaceGuid.PcdIsVmbfsBoot
   gMsvmPkgTokenSpaceGuid.PcdLogoFile
   gMsvmPkgTokenSpaceGuid.PcdPxeIpV6
+  gMsvmPkgTokenSpaceGuid.PcdVmbusEnabled
   gMsvmPkgTokenSpaceGuid.PcdVpciBootEnabled
 
 [Depex]
diff --git a/MsvmPkg/MsvmPkg.dec b/MsvmPkg/MsvmPkg.dec
index b326956e97..8ec8f9b7a4 100644
--- a/MsvmPkg/MsvmPkg.dec
+++ b/MsvmPkg/MsvmPkg.dec
@@ -298,6 +298,7 @@
   gMsvmPkgTokenSpaceGuid.PcdHostEmulatorsWhenHardwareIsolated|FALSE|BOOLEAN|0x6064
   gMsvmPkgTokenSpaceGuid.PcdTpmLocalityRegsEnabled|FALSE|BOOLEAN|0x6065
   gMsvmPkgTokenSpaceGuid.PcdMtrrsInitializedAtLoad|FALSE|BOOLEAN|0x6067
+  gMsvmPkgTokenSpaceGuid.PcdVmbusEnabled|TRUE|BOOLEAN|0x6068
 
   # UEFI_CONFIG_PROCESSOR_INFORMATION
   gMsvmPkgTokenSpaceGuid.PcdProcessorCount|0x0|UINT32|0x6032
diff --git a/MsvmPkg/MsvmPkgAARCH64.dsc b/MsvmPkg/MsvmPkgAARCH64.dsc
index 48dccb27c1..5d3d598193 100644
--- a/MsvmPkg/MsvmPkgAARCH64.dsc
+++ b/MsvmPkg/MsvmPkgAARCH64.dsc
@@ -697,6 +697,7 @@
   gMsvmPkgTokenSpaceGuid.PcdWatchdogEnabled|FALSE
   gMsvmPkgTokenSpaceGuid.PcdHostEmulatorsWhenHardwareIsolated|FALSE
   gMsvmPkgTokenSpaceGuid.PcdTpmLocalityRegsEnabled|FALSE
+  gMsvmPkgTokenSpaceGuid.PcdVmbusEnabled|TRUE
 
   # UEFI_CONFIG_PROCESSOR_INFORMATION
   gMsvmPkgTokenSpaceGuid.PcdProcessorCount|0x0
diff --git a/MsvmPkg/MsvmPkgX64.dsc b/MsvmPkg/MsvmPkgX64.dsc
index a62c04c226..2523eb8be1 100644
--- a/MsvmPkg/MsvmPkgX64.dsc
+++ b/MsvmPkg/MsvmPkgX64.dsc
@@ -715,6 +715,7 @@
   gMsvmPkgTokenSpaceGuid.PcdWatchdogEnabled|FALSE
   gMsvmPkgTokenSpaceGuid.PcdHostEmulatorsWhenHardwareIsolated|FALSE
   gMsvmPkgTokenSpaceGuid.PcdTpmLocalityRegsEnabled|FALSE
+  gMsvmPkgTokenSpaceGuid.PcdVmbusEnabled|TRUE
 
   # UEFI_CONFIG_PROCESSOR_INFORMATION
   gMsvmPkgTokenSpaceGuid.PcdProcessorCount|0x0
diff --git a/MsvmPkg/PlatformPei/AArch64/Mmu.c b/MsvmPkg/PlatformPei/AArch64/Mmu.c
index 093beaf4cc..898adafb02 100644
--- a/MsvmPkg/PlatformPei/AArch64/Mmu.c
+++ b/MsvmPkg/PlatformPei/AArch64/Mmu.c
@@ -404,6 +404,7 @@ ConfigureMmu(
     UINT64                        highMmioSize;
 #define MAX_VIRTUAL_MEMORY_MAP_DESCRIPTORS 6
     ARM_MEMORY_REGION_DESCRIPTOR virtualMemoryTable[MAX_VIRTUAL_MEMORY_MAP_DESCRIPTORS];
+    UINTN                         index = 0;
 
     //
     // Convert PCD page counts to byte addresses/sizes using safe
@@ -423,10 +424,8 @@ ConfigureMmu(
 
     //
     // Validate that MMIO regions fit within the physical address space.
-    // The host may provide MMIO ranges that extend beyond the CPU's
-    // physical address width, which would cause page table entries for
-    // unmappable addresses.
     //
+    if (highMmioSize > 0)
     {
         UINT64 highMmioEnd;
         if (RETURN_ERROR(SafeUint64Add(highMmioBaseAddress, highMmioSize, &highMmioEnd)))
@@ -447,62 +446,71 @@ ConfigureMmu(
     }
 
     //
-    // Fill table that drives the mmu setup functions.
+    // Build the memory map based on which MMIO gaps are present.
     //
-    // From zero to beginning of low MMIO gap.
-    virtualMemoryTable[0].PhysicalBase = 0;
-    virtualMemoryTable[0].VirtualBase = virtualMemoryTable[0].PhysicalBase;
-    virtualMemoryTable[0].Length = (SIZE_4GB - lowMmioSize);
-    virtualMemoryTable[0].Attributes = ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK;
-
-    // First MMIO gap.
-    virtualMemoryTable[1].PhysicalBase = virtualMemoryTable[0].PhysicalBase + virtualMemoryTable[0].Length;
-    virtualMemoryTable[1].VirtualBase = virtualMemoryTable[1].PhysicalBase;
-    virtualMemoryTable[1].Length = lowMmioSize;
-    virtualMemoryTable[1].Attributes = ARM_MEMORY_REGION_ATTRIBUTE_DEVICE;
-
-    // From 4GB to beginning of high MMIO gap.
-    virtualMemoryTable[2].PhysicalBase = virtualMemoryTable[1].PhysicalBase + virtualMemoryTable[1].Length;
-    virtualMemoryTable[2].VirtualBase = virtualMemoryTable[2].PhysicalBase;
-
-    if (RETURN_ERROR(SafeUint64Sub(highMmioBaseAddress, virtualMemoryTable[2].PhysicalBase, &virtualMemoryTable[2].Length)))
+
+    // From zero to beginning of low MMIO gap (or to 4GB if no low gap).
+    virtualMemoryTable[index].PhysicalBase = 0;
+    virtualMemoryTable[index].VirtualBase = 0;
+    virtualMemoryTable[index].Length = (SIZE_4GB - lowMmioSize);
+    virtualMemoryTable[index].Attributes = ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK;
+    index++;
+
+    // Low MMIO gap (only if nonzero size).
+    if (lowMmioSize > 0)
     {
-        DEBUG((DEBUG_ERROR, "ConfigureMmu: highMmioBaseAddress (0x%lx) < PhysicalBase (0x%lx)\n",
-            highMmioBaseAddress, virtualMemoryTable[2].PhysicalBase));
-        ASSERT(FALSE);
-        return EFI_INVALID_PARAMETER;
+        virtualMemoryTable[index].PhysicalBase = virtualMemoryTable[index - 1].PhysicalBase + virtualMemoryTable[index - 1].Length;
+        virtualMemoryTable[index].VirtualBase = virtualMemoryTable[index].PhysicalBase;
+        virtualMemoryTable[index].Length = lowMmioSize;
+        virtualMemoryTable[index].Attributes = ARM_MEMORY_REGION_ATTRIBUTE_DEVICE;
+        index++;
     }
 
-    virtualMemoryTable[2].Attributes = ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK;
+    if (highMmioSize > 0)
+    {
+        // From end of low gap (or 4GB) to beginning of high MMIO gap.
+        virtualMemoryTable[index].PhysicalBase = virtualMemoryTable[index - 1].PhysicalBase + virtualMemoryTable[index - 1].Length;
+        virtualMemoryTable[index].VirtualBase = virtualMemoryTable[index].PhysicalBase;
+
+        if (RETURN_ERROR(SafeUint64Sub(highMmioBaseAddress, virtualMemoryTable[index].PhysicalBase, &virtualMemoryTable[index].Length)))
+        {
+            DEBUG((DEBUG_ERROR, "ConfigureMmu: highMmioBaseAddress (0x%lx) < PhysicalBase (0x%lx)\n",
+                highMmioBaseAddress, virtualMemoryTable[index].PhysicalBase));
+            ASSERT(FALSE);
+            return EFI_INVALID_PARAMETER;
+        }
+
+        virtualMemoryTable[index].Attributes = ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK;
+        index++;
 
-    // Second MMIO gap.
-    virtualMemoryTable[3].PhysicalBase = virtualMemoryTable[2].PhysicalBase + virtualMemoryTable[2].Length;
-    virtualMemoryTable[3].VirtualBase = virtualMemoryTable[3].PhysicalBase;
-    virtualMemoryTable[3].Length = highMmioSize;
-    virtualMemoryTable[3].Attributes = ARM_MEMORY_REGION_ATTRIBUTE_DEVICE;
+        // High MMIO gap.
+        virtualMemoryTable[index].PhysicalBase = virtualMemoryTable[index - 1].PhysicalBase + virtualMemoryTable[index - 1].Length;
+        virtualMemoryTable[index].VirtualBase = virtualMemoryTable[index].PhysicalBase;
+        virtualMemoryTable[index].Length = highMmioSize;
+        virtualMemoryTable[index].Attributes = ARM_MEMORY_REGION_ATTRIBUTE_DEVICE;
+        index++;
+    }
 
     // To top of address space.
-    virtualMemoryTable[4].PhysicalBase = virtualMemoryTable[3].PhysicalBase + virtualMemoryTable[3].Length;
-    virtualMemoryTable[4].VirtualBase = virtualMemoryTable[4].PhysicalBase;
+    virtualMemoryTable[index].PhysicalBase = virtualMemoryTable[index - 1].PhysicalBase + virtualMemoryTable[index - 1].Length;
+    virtualMemoryTable[index].VirtualBase = virtualMemoryTable[index].PhysicalBase;
 
-    //
-    // Validate that the final region does not underflow. This should
-    // not happen given the MMIO validation above, but check defensively.
-    //
-    if (virtualMemoryTable[4].PhysicalBase > MaxAddress)
+    if (virtualMemoryTable[index].PhysicalBase > MaxAddress)
     {
         DEBUG((DEBUG_ERROR, "ConfigureMmu: PhysicalBase (0x%lx) > MaxAddress (0x%lx)\n",
-            virtualMemoryTable[4].PhysicalBase, MaxAddress));
+            virtualMemoryTable[index].PhysicalBase, MaxAddress));
         FAIL_FAST_UNEXPECTED_HOST_BEHAVIOR();
     }
 
-    virtualMemoryTable[4].Length = (MaxAddress - virtualMemoryTable[4].PhysicalBase) + 1;
-    virtualMemoryTable[4].Attributes = ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK;
+    virtualMemoryTable[index].Length = (MaxAddress - virtualMemoryTable[index].PhysicalBase) + 1;
+    virtualMemoryTable[index].Attributes = ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK;
+    index++;
 
-    virtualMemoryTable[5].PhysicalBase = 0;
-    virtualMemoryTable[5].VirtualBase = 0;
-    virtualMemoryTable[5].Length = 0;
-    virtualMemoryTable[5].Attributes = 0;
+    // End-of-table sentinel.
+    virtualMemoryTable[index].PhysicalBase = 0;
+    virtualMemoryTable[index].VirtualBase = 0;
+    virtualMemoryTable[index].Length = 0;
+    virtualMemoryTable[index].Attributes = 0;
 
     // Lookup the Table Level to get the information
     LookupAddresstoRootTable(MaxAddress, &T0SZ, &RootTableEntryCount);
diff --git a/MsvmPkg/PlatformPei/Config.c b/MsvmPkg/PlatformPei/Config.c
index 6532196828..2bb05c554c 100644
--- a/MsvmPkg/PlatformPei/Config.c
+++ b/MsvmPkg/PlatformPei/Config.c
@@ -762,6 +762,7 @@ DebugDumpUefiConfigStruct(
             DEBUG((DEBUG_VERBOSE, "\tWatchdogEnabled: %u\n", flags->Flags.WatchdogEnabled));
             DEBUG((DEBUG_VERBOSE, "\tTpmLocalityRegsEnabled: %u\n", flags->Flags.TpmLocalityRegsEnabled));
             DEBUG((DEBUG_VERBOSE, "\tMtrrsInitializedAtLoad: %u\n", flags->Flags.MtrrsInitializedAtLoad));
+            DEBUG((DEBUG_VERBOSE, "\tVmbusDisabled: %u\n", flags->Flags.VmbusDisabled));
             break;
         }
         case UefiConfigProcessorInformation:
@@ -941,6 +942,7 @@ ConfigSetUefiConfigFlags(
     PEI_FAIL_FAST_IF_FAILED(PcdSetBoolS(PcdWatchdogEnabled, (UINT8) ConfigFlags->Flags.WatchdogEnabled));
     PEI_FAIL_FAST_IF_FAILED(PcdSetBoolS(PcdTpmLocalityRegsEnabled, (UINT8) ConfigFlags->Flags.TpmLocalityRegsEnabled));
     PEI_FAIL_FAST_IF_FAILED(PcdSetBoolS(PcdMtrrsInitializedAtLoad, (UINT8) ConfigFlags->Flags.MtrrsInitializedAtLoad));
+    PEI_FAIL_FAST_IF_FAILED(PcdSetBoolS(PcdVmbusEnabled, !ConfigFlags->Flags.VmbusDisabled));
 
     //
     // If memory protections are enabled, configure the value into the HOB.
@@ -1558,16 +1560,20 @@ Return Value:
 
                 //
                 // Figure out which entry is the low gap, and which is the high.
+                // Use base >= 4GB as the indicator for the high gap. When an
+                // entry is empty (size=0) its base is typically 0, so it will
+                // naturally fall into the "low" bucket and be skipped downstream.
                 //
-                if (mmioRanges->Ranges[0].MmioPageNumberStart < mmioRanges->Ranges[1].MmioPageNumberStart)
+                if (mmioRanges->Ranges[0].MmioPageNumberStart >= (SIZE_4GB / SIZE_4KB) &&
+                    mmioRanges->Ranges[0].MmioSizeInPages > 0)
                 {
-                    lowGap = 0;
-                    highGap = 1;
+                    highGap = 0;
+                    lowGap = 1;
                 }
                 else
                 {
-                    lowGap = 1;
-                    highGap = 0;
+                    lowGap = 0;
+                    highGap = 1;
                 }
 
                 //
@@ -1585,35 +1591,37 @@ Return Value:
                     UINT64 highGapEnd;
 
                     //
-                    // Low gap size (in pages) must not exceed 4GB worth of pages,
-                    // and the low gap must end at or before the 4GB boundary.
+                    // Low gap: if size is nonzero, it must not exceed 4GB worth
+                    // of pages, and must end at or before the 4GB boundary.
                     //
-                    if ((lowGapSize > (SIZE_4GB / SIZE_4KB)) ||
-                        RETURN_ERROR(SafeUint64Add(lowGapBase, lowGapSize, &lowGapEnd)) ||
-                        (lowGapEnd > (SIZE_4GB / SIZE_4KB)))
+                    if (lowGapSize > 0)
                     {
-                        DEBUG((DEBUG_ERROR, "***Invalid low MMIO gap range\n"));
-                        FAIL_FAST_UNEXPECTED_HOST_BEHAVIOR();
+                        if ((lowGapSize > (SIZE_4GB / SIZE_4KB)) ||
+                            RETURN_ERROR(SafeUint64Add(lowGapBase, lowGapSize, &lowGapEnd)) ||
+                            (lowGapEnd > (SIZE_4GB / SIZE_4KB)))
+                        {
+                            DEBUG((DEBUG_ERROR, "***Invalid low MMIO gap range\n"));
+                            FAIL_FAST_UNEXPECTED_HOST_BEHAVIOR();
+                        }
                     }
 
                     //
-                    // High gap must start at or above the 4GB boundary (in pages)
-                    // to avoid unsigned underflow when computing memory region
-                    // lengths in ConfigureMmu().
+                    // High gap: if size is nonzero, it must start at or above
+                    // the 4GB boundary and must not overflow the address space.
                     //
-                    if (highGapBase < (SIZE_4GB / SIZE_4KB))
+                    if (highGapSize > 0)
                     {
-                        DEBUG((DEBUG_ERROR, "***Invalid high MMIO gap base below 4GB\n"));
-                        FAIL_FAST_UNEXPECTED_HOST_BEHAVIOR();
-                    }
+                        if (highGapBase < (SIZE_4GB / SIZE_4KB))
+                        {
+                            DEBUG((DEBUG_ERROR, "***Invalid high MMIO gap base below 4GB\n"));
+                            FAIL_FAST_UNEXPECTED_HOST_BEHAVIOR();
+                        }
 
-                    //
-                    // High gap must not overflow the address space.
-                    //
-                    if (RETURN_ERROR(SafeUint64Add(highGapBase, highGapSize, &highGapEnd)))
-                    {
-                        DEBUG((DEBUG_ERROR, "***High MMIO gap range overflow\n"));
-                        FAIL_FAST_UNEXPECTED_HOST_BEHAVIOR();
+                        if (RETURN_ERROR(SafeUint64Add(highGapBase, highGapSize, &highGapEnd)))
+                        {
+                            DEBUG((DEBUG_ERROR, "***High MMIO gap range overflow\n"));
+                            FAIL_FAST_UNEXPECTED_HOST_BEHAVIOR();
+                        }
                     }
                 }
 
@@ -1794,6 +1802,8 @@ Return Value:
         header = (UEFI_CONFIG_HEADER*) ((UINT64) header + header->Length);
     }
 
+
+
     if (requiredStructures.AsUINT64 != AllStructuresFound)
     {
         DEBUG((DEBUG_ERROR, "Missing required structures, found structures: 0x%x\n", requiredStructures.AsUINT64));
diff --git a/MsvmPkg/PlatformPei/Platform.c b/MsvmPkg/PlatformPei/Platform.c
index e513a8be37..fcdd8c78c7 100644
--- a/MsvmPkg/PlatformPei/Platform.c
+++ b/MsvmPkg/PlatformPei/Platform.c
@@ -701,45 +701,54 @@ Return Value:
 #endif
 
     //
-    // Low and high MMIO range
+    // Low and high MMIO ranges. Declared based on nonzero size rather than
+    // VMBus state, since chipset devices (e.g. TPM) may need low MMIO even
+    // without VMBus.
     //
+    if (PcdGet64(PcdLowMmioGapSizeInPages) > 0)
+    {
 #if defined (MDE_CPU_X64)
-    HobAddMmioRange(
-        PcdGet64(PcdLowMmioGapBasePageNumber) * SIZE_4KB,
-        PcdGet64(PcdLowMmioGapSizeInPages) * SIZE_4KB
-        );
+        HobAddMmioRange(
+            PcdGet64(PcdLowMmioGapBasePageNumber) * SIZE_4KB,
+            PcdGet64(PcdLowMmioGapSizeInPages) * SIZE_4KB
+            );
 #elif defined(MDE_CPU_AARCH64)
-    //
-    // For ARM64 we are still using the BiosDevice for runtime services.
-    // However the registers are now in MMIO space instead of IO space. Therefore the
-    // addresses need to be translated after the guest calls SetVirtualAddressMap.
-    // To have the address range included with the guest's call to SetVirtualAddressMap
-    // the range has to be declared as DXE runtime memory. That has to be done in DXE phase
-    // by a driver so the range can't be declared as MMIO here.  Therefore leave that page
-    // out of this early general platform declaration.
-    //
-    UINT64 GapBase = PcdGet32(PcdBiosBaseAddress);
-    UINT64 GapSize = SIZE_4KB;
-    UINT64 FirstRangeBase = PcdGet64(PcdLowMmioGapBasePageNumber) * SIZE_4KB;
-    UINT64 FirstRangeSize = GapBase - FirstRangeBase;
-    UINT64 SecondRangeBase = FirstRangeBase + FirstRangeSize + GapSize;
-    UINT64 SecondRangeSize = (PcdGet64(PcdLowMmioGapSizeInPages) * SIZE_4KB) -
-                             (FirstRangeSize + GapSize);
-
-    HobAddMmioRange(
-        FirstRangeBase,
-        FirstRangeSize
-        );
+        //
+        // For ARM64 we are still using the BiosDevice for runtime services.
+        // However the registers are now in MMIO space instead of IO space. Therefore the
+        // addresses need to be translated after the guest calls SetVirtualAddressMap.
+        // To have the address range included with the guest's call to SetVirtualAddressMap
+        // the range has to be declared as DXE runtime memory. That has to be done in DXE phase
+        // by a driver so the range can't be declared as MMIO here.  Therefore leave that page
+        // out of this early general platform declaration.
+        //
+        UINT64 GapBase = PcdGet32(PcdBiosBaseAddress);
+        UINT64 GapSize = SIZE_4KB;
+        UINT64 FirstRangeBase = PcdGet64(PcdLowMmioGapBasePageNumber) * SIZE_4KB;
+        UINT64 FirstRangeSize = GapBase - FirstRangeBase;
+        UINT64 SecondRangeBase = FirstRangeBase + FirstRangeSize + GapSize;
+        UINT64 SecondRangeSize = (PcdGet64(PcdLowMmioGapSizeInPages) * SIZE_4KB) -
+                                 (FirstRangeSize + GapSize);
+
+        HobAddMmioRange(
+            FirstRangeBase,
+            FirstRangeSize
+            );
 
-    HobAddMmioRange(
-        SecondRangeBase,
-        SecondRangeSize
-        );
+        HobAddMmioRange(
+            SecondRangeBase,
+            SecondRangeSize
+            );
 #endif
-    HobAddMmioRange(
-        PcdGet64(PcdHighMmioGapBasePageNumber) * SIZE_4KB,
-        PcdGet64(PcdHighMmioGapSizeInPages) * SIZE_4KB
-        );
+    }
+
+    if (PcdGet64(PcdHighMmioGapSizeInPages) > 0)
+    {
+        HobAddMmioRange(
+            PcdGet64(PcdHighMmioGapBasePageNumber) * SIZE_4KB,
+            PcdGet64(PcdHighMmioGapSizeInPages) * SIZE_4KB
+            );
+    }
 
     //
     // Read PcieBarApertures first -- these determine which bridges UEFI
diff --git a/MsvmPkg/PlatformPei/PlatformPei.inf b/MsvmPkg/PlatformPei/PlatformPei.inf
index 3fd7c92cc0..7eb5b21818 100644
--- a/MsvmPkg/PlatformPei/PlatformPei.inf
+++ b/MsvmPkg/PlatformPei/PlatformPei.inf
@@ -196,6 +196,7 @@
     gMsvmPkgTokenSpaceGuid.PcdHostEmulatorsWhenHardwareIsolated
     gMsvmPkgTokenSpaceGuid.PcdTpmLocalityRegsEnabled
     gMsvmPkgTokenSpaceGuid.PcdMtrrsInitializedAtLoad
+    gMsvmPkgTokenSpaceGuid.PcdVmbusEnabled
     gMsvmPkgTokenSpaceGuid.PcdPcieBarAperturesPtr
     gMsvmPkgTokenSpaceGuid.PcdPcieBarAperturesSize
 
diff --git a/MsvmPkg/VmbusDxe/VmbusDxe.inf b/MsvmPkg/VmbusDxe/VmbusDxe.inf
index 0e09956d11..ffa71195fa 100644
--- a/MsvmPkg/VmbusDxe/VmbusDxe.inf
+++ b/MsvmPkg/VmbusDxe/VmbusDxe.inf
@@ -56,6 +56,7 @@
     gInternalEventServicesProtocolGuid  ## CONSUMES
 
 [Pcd]
+    gMsvmPkgTokenSpaceGuid.PcdVmbusEnabled                                  ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdVmbusSintVector                               ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdVmbusSintIndex                                ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdIsolationSharedGpaBoundary                    ## CONSUMES
diff --git a/MsvmPkg/VmbusDxe/VmbusRoot.c b/MsvmPkg/VmbusDxe/VmbusRoot.c
index 9aa1662b37..86522fcc47 100644
--- a/MsvmPkg/VmbusDxe/VmbusRoot.c
+++ b/MsvmPkg/VmbusDxe/VmbusRoot.c
@@ -2282,6 +2282,12 @@ VmbusDriverInitialize (
 
     DEBUG((DEBUG_VERBOSE, ">>> %a\n", __func__));
 
+    if (!PcdGetBool(PcdVmbusEnabled))
+    {
+        DEBUG((DEBUG_INFO, "VMBus is disabled by configuration, not starting VMBus driver.\n"));
+        return EFI_UNSUPPORTED;
+    }
+
     mVmbusImageHandle = ImageHandle;
 
     //