6 files changed, 177 insertions, 4 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 8ccb2d5f0..e8aefb6b4 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -140,6 +140,8 @@ add_library(core STATIC
     hle/kernel/svc_wrap.h
     hle/kernel/thread.cpp
     hle/kernel/thread.h
+    hle/kernel/transfer_memory.cpp
+    hle/kernel/transfer_memory.h
     hle/kernel/vm_manager.cpp
     hle/kernel/vm_manager.h
     hle/kernel/wait_object.cpp
diff --git a/src/core/hle/kernel/object.cpp b/src/core/hle/kernel/object.cpp
index 8870463d0..217144efc 100644
--- a/src/core/hle/kernel/object.cpp
+++ b/src/core/hle/kernel/object.cpp
@@ -23,6 +23,7 @@ bool Object::IsWaitable() const {
     case HandleType::Unknown:
     case HandleType::WritableEvent:
     case HandleType::SharedMemory:
+    case HandleType::TransferMemory:
     case HandleType::AddressArbiter:
     case HandleType::ResourceLimit:
     case HandleType::ClientPort:
diff --git a/src/core/hle/kernel/object.h b/src/core/hle/kernel/object.h
index 4c2505908..3f6baa094 100644
--- a/src/core/hle/kernel/object.h
+++ b/src/core/hle/kernel/object.h
@@ -22,6 +22,7 @@ enum class HandleType : u32 {
     WritableEvent,
     ReadableEvent,
     SharedMemory,
+    TransferMemory,
     Thread,
     Process,
     AddressArbiter,
diff --git a/src/core/hle/kernel/svc.cpp b/src/core/hle/kernel/svc.cpp
index 77d0e3d96..c8b9e8aeb 100644
--- a/src/core/hle/kernel/svc.cpp
+++ b/src/core/hle/kernel/svc.cpp
@@ -32,6 +32,7 @@
 #include "core/hle/kernel/svc.h"
 #include "core/hle/kernel/svc_wrap.h"
 #include "core/hle/kernel/thread.h"
+#include "core/hle/kernel/transfer_memory.h"
 #include "core/hle/kernel/writable_event.h"
 #include "core/hle/lock.h"
 #include "core/hle/result.h"
@@ -1577,11 +1578,15 @@ static ResultCode CreateTransferMemory(Handle* handle, VAddr addr, u64 size, u32
     }
 
     auto& kernel = Core::System::GetInstance().Kernel();
-    auto process = kernel.CurrentProcess();
-    auto& handle_table = process->GetHandleTable();
-    const auto shared_mem_handle = SharedMemory::Create(kernel, process, size, perms, perms, addr);
+    auto transfer_mem_handle = TransferMemory::Create(kernel, addr, size, perms);
 
-    CASCADE_RESULT(*handle, handle_table.Create(shared_mem_handle));
+    auto& handle_table = kernel.CurrentProcess()->GetHandleTable();
+    const auto result = handle_table.Create(std::move(transfer_mem_handle));
+    if (result.Failed()) {
+        return result.Code();
+    }
+
+    *handle = *result;
     return RESULT_SUCCESS;
 }
 
diff --git a/src/core/hle/kernel/transfer_memory.cpp b/src/core/hle/kernel/transfer_memory.cpp
new file mode 100644
index 000000000..23228e1b5
--- /dev/null
+++ b/src/core/hle/kernel/transfer_memory.cpp
@@ -0,0 +1,73 @@
+// Copyright 2019 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "core/hle/kernel/errors.h"
+#include "core/hle/kernel/kernel.h"
+#include "core/hle/kernel/process.h"
+#include "core/hle/kernel/shared_memory.h"
+#include "core/hle/kernel/transfer_memory.h"
+#include "core/hle/result.h"
+
+namespace Kernel {
+
+TransferMemory::TransferMemory(KernelCore& kernel) : Object{kernel} {}
+TransferMemory::~TransferMemory() = default;
+
+SharedPtr<TransferMemory> TransferMemory::Create(KernelCore& kernel, VAddr base_address,
+                                                 size_t size, MemoryPermission permissions) {
+    SharedPtr<TransferMemory> transfer_memory{new TransferMemory(kernel)};
+
+    transfer_memory->base_address = base_address;
+    transfer_memory->memory_size = size;
+    transfer_memory->owner_permissions = permissions;
+    transfer_memory->owner_process = kernel.CurrentProcess();
+
+    return transfer_memory;
+}
+
+ResultCode TransferMemory::MapMemory(VAddr address, size_t size, MemoryPermission permissions) {
+    if (memory_size != size) {
+        return ERR_INVALID_SIZE;
+    }
+
+    if (owner_permissions != permissions) {
+        return ERR_INVALID_STATE;
+    }
+
+    if (is_mapped) {
+        return ERR_INVALID_STATE;
+    }
+
+    const auto map_state = owner_permissions == MemoryPermission::None
+                               ? MemoryState::TransferMemoryIsolated
+                               : MemoryState::TransferMemory;
+    auto& vm_manager = owner_process->VMManager();
+    const auto map_result = vm_manager.MapMemoryBlock(
+        address, std::make_shared<std::vector<u8>>(size), 0, size, map_state);
+
+    if (map_result.Failed()) {
+        return map_result.Code();
+    }
+
+    is_mapped = true;
+    return RESULT_SUCCESS;
+}
+
+ResultCode TransferMemory::UnmapMemory(VAddr address, size_t size) {
+    if (memory_size != size) {
+        return ERR_INVALID_SIZE;
+    }
+
+    auto& vm_manager = owner_process->VMManager();
+    const auto result = vm_manager.UnmapRange(address, size);
+
+    if (result.IsError()) {
+        return result;
+    }
+
+    is_mapped = false;
+    return RESULT_SUCCESS;
+}
+
+} // namespace Kernel
diff --git a/src/core/hle/kernel/transfer_memory.h b/src/core/hle/kernel/transfer_memory.h
new file mode 100644
index 000000000..ec294951e
--- /dev/null
+++ b/src/core/hle/kernel/transfer_memory.h
@@ -0,0 +1,91 @@
+// Copyright 2019 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "core/hle/kernel/object.h"
+
+union ResultCode;
+
+namespace Kernel {
+
+class KernelCore;
+class Process;
+
+enum class MemoryPermission : u32;
+
+/// Defines the interface for transfer memory objects.
+///
+/// Transfer memory is typically used for the purpose of
+/// transferring memory between separate process instances,
+/// thus the name.
+///
+class TransferMemory final : public Object {
+public:
+    static constexpr HandleType HANDLE_TYPE = HandleType::TransferMemory;
+
+    static SharedPtr<TransferMemory> Create(KernelCore& kernel, VAddr base_address, size_t size,
+                                            MemoryPermission permissions);
+
+    TransferMemory(const TransferMemory&) = delete;
+    TransferMemory& operator=(const TransferMemory&) = delete;
+
+    TransferMemory(TransferMemory&&) = delete;
+    TransferMemory& operator=(TransferMemory&&) = delete;
+
+    std::string GetTypeName() const override {
+        return "TransferMemory";
+    }
+
+    std::string GetName() const override {
+        return GetTypeName();
+    }
+
+    HandleType GetHandleType() const override {
+        return HANDLE_TYPE;
+    }
+
+    /// Attempts to map transfer memory with the given range and memory permissions.
+    ///
+    /// @param address     The base address to being mapping memory at.
+    /// @param size        The size of the memory to map, in bytes.
+    /// @param permissions The memory permissions to check against when mapping memory.
+    ///
+    /// @pre The given address, size, and memory permissions must all match
+    ///      the same values that were given when creating the transfer memory
+    ///      instance.
+    ///
+    ResultCode MapMemory(VAddr address, size_t size, MemoryPermission permissions);
+
+    /// Unmaps the transfer memory with the given range
+    ///
+    /// @param address The base address to begin unmapping memory at.
+    /// @param size    The size of the memory to unmap, in bytes.
+    ///
+    /// @pre The given address and size must be the same as the ones used
+    ///      to create the transfer memory instance.
+    ///
+    ResultCode UnmapMemory(VAddr address, size_t size);
+
+private:
+    explicit TransferMemory(KernelCore& kernel);
+    ~TransferMemory() override;
+
+    /// The base address for the memory managed by this instance.
+    VAddr base_address = 0;
+
+    /// Size of the memory, in bytes, that this instance manages.
+    size_t memory_size = 0;
+
+    /// The memory permissions that are applied to this instance.
+    MemoryPermission owner_permissions{};
+
+    /// The process that this transfer memory instance was created under.
+    Process* owner_process = nullptr;
+
+    /// Whether or not this transfer memory instance has mapped memory.
+    bool is_mapped = false;
+};
+
+} // namespace Kernel