core: Implement new memory manager (#133)

* core: Implement new memory manager

* ci: Attempt to fix linux build

* code: Fix a few build errors

src/core/address_space.h

@@ -0,0 +1,59 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <memory>
+#include "common/enum.h"
+#include "common/types.h"
+
+namespace Core {
+
+enum class MemoryPermission : u32 {
+    Read = 1 << 0,
+    Write = 1 << 1,
+    ReadWrite = Read | Write,
+    Execute = 1 << 2,
+};
+DECLARE_ENUM_FLAG_OPERATORS(MemoryPermission)
+
+/**
+ * Represents the user virtual address space backed by a dmem memory block
+ */
+class AddressSpace {
+public:
+    explicit AddressSpace();
+    ~AddressSpace();
+
+    [[nodiscard]] u8* VirtualBase() noexcept {
+        return virtual_base;
+    }
+    [[nodiscard]] const u8* VirtualBase() const noexcept {
+        return virtual_base;
+    }
+
+    /**
+     * @brief Maps memory to the specified virtual address.
+     * @param virtual_addr The base address to place the mapping.
+     *        If zero is provided an address in system managed area is picked.
+     * @param size The size of the area to map.
+     * @param phys_addr The offset of the backing file handle to map.
+     *                  The same backing region may be aliased into different virtual regions.
+     *                  If zero is provided the mapping is considered as private.
+     * @return A pointer to the mapped memory.
+     */
+    void* Map(VAddr virtual_addr, size_t size, u64 alignment = 0, PAddr phys_addr = 0);
+
+    /// Unmaps specified virtual memory area.
+    void Unmap(VAddr virtual_addr, size_t size);
+
+    void Protect(VAddr virtual_addr, size_t size, MemoryPermission perms);
+
+private:
+    struct Impl;
+    std::unique_ptr<Impl> impl;
+    u8* backing_base{};
+    u8* virtual_base{};
+};
+
+} // namespace Core