[common/core/dynarmic] Optimize page table allocations (#4219)

Reduces the page entries from 32 bytes to 8 and rewrites `VirtualBuffer` to be more efficient in memory usage and specifically for large zero regions.

The page table will now only reserve 1GiB instead of 4GiB and of this memory it should only use at most ~8MiB.

This PR has the side effect of using Eden on Windows on low memory systems much more plausible since it would previously require ~10GiB of committable memory at front (despite using ~5-6 at most, inadvertently stalling other processes) where as now it should only require around the amount that it'll actually use.

Co-authored-by: Lizzie <lizzie@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4219
Reviewed-by: Maufeat <sahyno1996@gmail.com>
Reviewed-by: lizzie <lizzie@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>

src/common/virtual_buffer.h

@@ -1,84 +0,0 @@
-// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
-// SPDX-License-Identifier: GPL-3.0-or-later
-
-// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-#pragma once
-
-#include <utility>
-
-namespace Common {
-
-void* AllocateMemoryPages(std::size_t size) noexcept;
-void FreeMemoryPages(void* base, std::size_t size) noexcept;
-
-template <typename T>
-class VirtualBuffer final {
-public:
-    // TODO: Uncomment this and change Common::PageTable::PageInfo to be trivially constructible
-    // using std::atomic_ref once libc++ has support for it
-    // static_assert(
-    //     std::is_trivially_constructible_v<T>,
-    //     "T must be trivially constructible, as non-trivial constructors will not be executed "
-    //     "with the current allocator");
-
-    constexpr VirtualBuffer() = default;
-    explicit VirtualBuffer(std::size_t count) noexcept
-        : alloc_size{count * sizeof(T)}
-    {
-        base_ptr = reinterpret_cast<T*>(AllocateMemoryPages(alloc_size));
-    }
-
-    ~VirtualBuffer() noexcept {
-        FreeMemoryPages(base_ptr, alloc_size);
-    }
-
-    VirtualBuffer(const VirtualBuffer&) = delete;
-    VirtualBuffer& operator=(const VirtualBuffer&) = delete;
-
-    VirtualBuffer(VirtualBuffer&& other) noexcept
-        : alloc_size{std::exchange(other.alloc_size, 0)}
-        , base_ptr{std::exchange(other.base_ptr, nullptr)}
-    {}
-
-    VirtualBuffer& operator=(VirtualBuffer&& other) noexcept {
-        alloc_size = std::exchange(other.alloc_size, 0);
-        base_ptr = std::exchange(other.base_ptr, nullptr);
-        return *this;
-    }
-
-    void resize(std::size_t count) noexcept {
-        if (auto const new_size = count * sizeof(T); new_size != alloc_size) {
-            FreeMemoryPages(base_ptr, alloc_size);
-            alloc_size = new_size;
-            base_ptr = reinterpret_cast<T*>(AllocateMemoryPages(alloc_size));
-        }
-    }
-
-    [[nodiscard]] constexpr const T& operator[](std::size_t index) const noexcept {
-        return base_ptr[index];
-    }
-
-    [[nodiscard]] constexpr T& operator[](std::size_t index) noexcept {
-        return base_ptr[index];
-    }
-
-    [[nodiscard]] constexpr T* data() noexcept {
-        return base_ptr;
-    }
-
-    [[nodiscard]] constexpr const T* data() const noexcept {
-        return base_ptr;
-    }
-
-    [[nodiscard]] constexpr std::size_t size() const noexcept {
-        return alloc_size / sizeof(T);
-    }
-
-private:
-    std::size_t alloc_size{};
-    T* base_ptr{};
-};
-
-} // namespace Common