From 2da096022c5b097f854974f76dba8cc4f769513d Mon Sep 17 00:00:00 2001
From: ergo720 <csteven129@gmail.com>
Date: Sat, 3 Mar 2018 23:53:19 +0100
Subject: [PATCH] MmUnmapIoSpace

---
 import/OpenXDK/include/xboxkrnl/mm.h |  2 +-
 src/CxbxKrnl/EmuKrnlMm.cpp           | 12 ++-----
 src/CxbxKrnl/VMManager.cpp           | 47 ++++++++++++++++++++++++++--
 src/CxbxKrnl/VMManager.h             |  2 ++
 4 files changed, 50 insertions(+), 13 deletions(-)

diff --git a/import/OpenXDK/include/xboxkrnl/mm.h b/import/OpenXDK/include/xboxkrnl/mm.h
index 2273f910d..d70315b7a 100644
--- a/import/OpenXDK/include/xboxkrnl/mm.h
+++ b/import/OpenXDK/include/xboxkrnl/mm.h
@@ -184,7 +184,7 @@ XBSYSAPI EXPORTNUM(182) VOID NTAPI MmSetAddressProtect
 // ******************************************************************
 // * MmUnmapIoSpace
 // ******************************************************************
-XBSYSAPI EXPORTNUM(183) NTSTATUS NTAPI MmUnmapIoSpace
+XBSYSAPI EXPORTNUM(183) VOID NTAPI MmUnmapIoSpace
 (
     IN PVOID BaseAddress,
     IN ULONG NumberOfBytes
diff --git a/src/CxbxKrnl/EmuKrnlMm.cpp b/src/CxbxKrnl/EmuKrnlMm.cpp
index f1dd88f1e..09aef7d71 100644
--- a/src/CxbxKrnl/EmuKrnlMm.cpp
+++ b/src/CxbxKrnl/EmuKrnlMm.cpp
@@ -521,7 +521,7 @@ XBSYSAPI EXPORTNUM(182) xboxkrnl::VOID NTAPI xboxkrnl::MmSetAddressProtect
 // Unmaps a virtual address mapping made by MmMapIoSpace.
 //
 // Differences from NT: None.
-XBSYSAPI EXPORTNUM(183) xboxkrnl::NTSTATUS NTAPI xboxkrnl::MmUnmapIoSpace
+XBSYSAPI EXPORTNUM(183) xboxkrnl::VOID NTAPI xboxkrnl::MmUnmapIoSpace
 (
 	IN PVOID BaseAddress,
 	IN ULONG NumberOfBytes
@@ -532,15 +532,7 @@ XBSYSAPI EXPORTNUM(183) xboxkrnl::NTSTATUS NTAPI xboxkrnl::MmUnmapIoSpace
 		LOG_FUNC_ARG(NumberOfBytes)
 	LOG_FUNC_END;
 
-	if ((xbaddr)BaseAddress >= XBOX_WRITE_COMBINED_BASE) { // 0xF0000000
-		// Don't free hardware devices (flash, NV2A, etc)
-	}
-	else {
-		g_VMManager.Deallocate((VAddr)BaseAddress);
-		LOG_INCOMPLETE();
-	}
-
-	RETURN(STATUS_SUCCESS);
+	g_VMManager.UnmapDeviceMemory((VAddr)BaseAddress, NumberOfBytes);
 }
 
 // ******************************************************************
diff --git a/src/CxbxKrnl/VMManager.cpp b/src/CxbxKrnl/VMManager.cpp
index 111763307..941e5d917 100644
--- a/src/CxbxKrnl/VMManager.cpp
+++ b/src/CxbxKrnl/VMManager.cpp
@@ -665,7 +665,7 @@ void VMManager::DeAllocateContiguous(VAddr addr)
 	PFN EndingPfn;
 	VMAIter it;
 
-	assert(CHECK_ALIGNMENT(addr, PAGE_SIZE)); // all starting addresses from the contiguous region are page aligned
+	assert(CHECK_ALIGNMENT(addr, PAGE_SIZE)); // all starting addresses in the contiguous region are page aligned
 
 	Lock();
 
@@ -706,7 +706,7 @@ PFN_COUNT VMManager::DeAllocateSystemMemory(PageType BusyType, VAddr addr, size_
 	PFN_COUNT PteNumber;
 	VMAIter it;
 
-	assert(CHECK_ALIGNMENT(addr, PAGE_SIZE)); // all starting addresses from the system region are page aligned
+	assert(CHECK_ALIGNMENT(addr, PAGE_SIZE)); // all starting addresses in the system region are page aligned
 
 	Lock();
 
@@ -744,6 +744,49 @@ PFN_COUNT VMManager::DeAllocateSystemMemory(PageType BusyType, VAddr addr, size_
 	RETURN(PteNumber);
 }
 
+void VMManager::UnmapDeviceMemory(VAddr addr, size_t Size)
+{
+	LOG_FUNC_BEGIN
+		LOG_FUNC_ARG(addr);
+		LOG_FUNC_ARG(Size);
+	LOG_FUNC_END;
+
+	if (addr >= SYSTEM_MEMORY_BASE && addr + Size <= SYSTEM_MEMORY_END)
+	{
+		// The allocation is inside the system region, so it must have been mapped by us. Unmap it
+
+		MMPTE TempPte;
+		PMMPTE StartingPte;
+		PMMPTE EndingPte;
+		PFN_COUNT PteNumber;
+		VMAIter it;
+
+		assert(CHECK_ALIGNMENT(addr, PAGE_SIZE)); // all starting addresses in the system region are page aligned
+
+		Lock();
+
+		it = CheckExistenceVMA(addr, MemoryRegionType::System, ROUND_UP_4K(Size));
+
+		if (it == m_MemoryRegionArray[MemoryRegionType::System].RegionMap.end() || it->second.type == VMAType::Free)
+		{
+			Unlock();
+			return;
+		}
+
+		StartingPte = GetPteAddress(addr);
+		EndingPte = StartingPte + (it->second.size >> PAGE_SHIFT) - 1;
+		PteNumber = EndingPte - StartingPte + 1;
+
+		WritePte(StartingPte, EndingPte, TempPte, 0, true);
+		DestructVMA(it, MemoryRegionType::System);
+
+		Unlock();
+		return;
+	}
+
+	// Don't free hardware devices (flash, NV2A, etc) -> no operation
+}
+
 void VMManager::Protect(VAddr target, size_t size, DWORD new_perms)
 {
 	LOG_FUNC_BEGIN
diff --git a/src/CxbxKrnl/VMManager.h b/src/CxbxKrnl/VMManager.h
index db0faf65b..15e328a8a 100644
--- a/src/CxbxKrnl/VMManager.h
+++ b/src/CxbxKrnl/VMManager.h
@@ -142,6 +142,8 @@ class VMManager : public PhysicalMemory
 		PFN_COUNT DeAllocateSystemMemory(PageType BusyType, VAddr addr, size_t Size /*MemoryRegionType Type*/);
 		// deallocates memory in the contiguous region
 		void DeAllocateContiguous(VAddr addr);
+		// unmaps device memory in the system region
+		void UnmapDeviceMemory(VAddr addr, size_t Size);
 		// deallocate a block of memory
 		void Deallocate(VAddr addr);
 		// changes the protections of a memory region