[common/core] Reimplement virtual buffers

src/common/CMakeLists.txt

@@ -109,6 +109,8 @@ add_library(
     settings_setting.h
     slot_vector.h
     socket_types.h
+    sparse_large_vector.cpp
+    sparse_large_vector.h
     spin_lock.h
     stb.cpp
     stb.h
@@ -136,8 +138,6 @@ add_library(
     uuid.cpp
     uuid.h
     vector_math.h
-    virtual_buffer.cpp
-    virtual_buffer.h
     zstd_compression.cpp
     zstd_compression.h
     fs/ryujinx_compat.h fs/ryujinx_compat.cpp

src/common/fiber.cpp

@@ -9,7 +9,6 @@
 
 #include "common/assert.h"
 #include "common/fiber.h"
-#include "common/virtual_buffer.h"
 
 #include <boost/context/detail/fcontext.hpp>
 

src/common/host_memory.cpp

@@ -179,6 +179,14 @@ public:
         Release();
     }
 
+    void* Allocate(size_t size) {
+        auto* ptr = VirtualAlloc(nullptr, size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
+        if (ptr == nullptr) {
+            LOG_CRITICAL(HW_Memory, "Failed to allocate fallback buffer with size {:#x}, error {}", size, GetLastError());
+        }
+        return VirtualAlloc(nullptr, size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
+    }
+
     void Map(size_t virtual_offset, size_t host_offset, size_t length, MemoryPermission perms) {
         std::unique_lock lock{placeholder_mutex};
         if (!IsNiechePlaceholder(virtual_offset, length)) {
@@ -571,6 +579,14 @@ public:
         Release();
     }
 
+    void* Allocate(size_t size) {
+        auto* ptr = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+        if (ptr == MAP_FAILED) {
+            LOG_CRITICAL(HW_Memory, "Failed to allocate fallback buffer with size {:#x}, {}", size, strerror(errno));
+        }
+        return ptr;
+    }
+
     void Map(size_t virtual_offset, size_t host_offset, size_t length, MemoryPermission perms) {
         // Intersect the range with our address space.
         AdjustMap(&virtual_offset, &length);
@@ -691,8 +707,7 @@ HostMemory::HostMemory(size_t backing_size_, size_t virtual_size_)
 {
 #if defined(__OPENORBIS__) || defined(__managarm__)
     LOG_WARNING(HW_Memory, "Platform doesn't support fastmem");
-    fallback_buffer.emplace(backing_size);
-    backing_base = fallback_buffer->data();
+    backing_base = malloc(backing_size);
     virtual_base = nullptr;
 #else
     // Try to allocate a fastmem arena.
@@ -707,16 +722,28 @@ HostMemory::HostMemory(size_t backing_size_, size_t virtual_size_)
             virtual_base_offset = virtual_base - impl->virtual_base;
         }
     } else {
-        impl.reset();
         LOG_WARNING(HW_Memory, "Platform can support fastmem, but can't create it");
-        fallback_buffer.emplace(backing_size);
-        backing_base = fallback_buffer->data();
+        fallback_buffer = true;
+        backing_base = static_cast<u8*>(impl->Allocate(backing_size));
         virtual_base = nullptr;
+        impl.reset();
     }
 #endif
 }
 
-HostMemory::~HostMemory() = default;
+HostMemory::~HostMemory() {
+#if defined(__OPENORBIS__) || defined(__managarm__)
+    free(backing_base);
+#elif _WIN32
+    if (fallback_buffer) {
+        VirtualFree(backing_base, backing_size, MEM_RELEASE);
+    }
+#else
+    if (fallback_buffer) {
+        munmap(backing_base, backing_size);
+    }
+#endif
+}
 
 HostMemory::HostMemory(HostMemory&&) noexcept = default;
 

src/common/host_memory.h

@@ -10,7 +10,6 @@
 #include <optional>
 #include "common/common_funcs.h"
 #include "common/common_types.h"
-#include "common/virtual_buffer.h"
 
 namespace Common {
 
@@ -86,7 +85,7 @@ private:
     u8* virtual_base{};
     size_t virtual_base_offset{};
     // Windows requires it for kernels whom lack proper support for some functions!
-    std::optional<Common::VirtualBuffer<u8>> fallback_buffer;
+    bool fallback_buffer;
 };
 
 } // namespace Common

src/common/page_table.cpp

@@ -43,7 +43,7 @@ bool PageTable::ContinueTraversal(TraversalEntry* out_entry, TraversalContext* c
 
 void PageTable::Resize(std::size_t address_space_width_in_bits, std::size_t page_size_in_bits) {
     auto const num_page_table_entries = 1ULL << (address_space_width_in_bits - page_size_in_bits);
-    entries.resize(num_page_table_entries);
+    entries.ResizeAndClear(num_page_table_entries);
     current_address_space_width_in_bits = address_space_width_in_bits;
     page_size = 1ULL << page_size_in_bits;
 }

src/common/page_table.h

@@ -9,8 +9,8 @@
 #include <atomic>
 
 #include "common/common_types.h"
+#include "common/sparse_large_vector.h"
 #include "common/typed_address.h"
-#include "common/virtual_buffer.h"
 
 namespace Common {
 
@@ -139,7 +139,7 @@ struct PageTable {
         u64 addr;
         u64 padding;
     };
-    VirtualBuffer<PageEntryData> entries;
+    SparseLargeVector<PageEntryData> entries;
     static_assert(sizeof(PageEntryData) == 32);
 
     u8* fastmem_arena{};

src/common/sparse_large_vector.cpp

@@ -0,0 +1,135 @@
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+/* virtual_buffer.cpp */
+// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#ifdef _WIN32
+#include <windows.h>
+#include <mutex>
+#else
+#include <sys/mman.h>
+#endif
+
+#include "common/alignment.h"
+#include "common/assert.h"
+#include "common/sparse_large_vector.h"
+
+namespace Common {
+
+#ifdef _WIN32
+static std::vector<std::pair<u64, u64>> vector_regions;
+
+// Workaround for handling non-commited memory accessed by Dynarmic; usually result of an error
+static LONG WINAPI FakePageFaultHandler(PEXCEPTION_POINTERS info) {
+    DWORD code = info->ExceptionRecord->ExceptionCode;
+    u64 exception_addr = reinterpret_cast<u64>(info->ExceptionRecord->ExceptionAddress);
+
+    if (code != EXCEPTION_ACCESS_VIOLATION) {
+        // Not our problem
+        return EXCEPTION_CONTINUE_SEARCH;
+    }
+
+    u64 addr = 0, addr2 = 0;
+
+    for (auto region: vector_regions) {
+        auto addr_shifted = exception_addr >> HostPageBits;
+        if (region.first <= addr_shifted && addr_shifted <= region.second) {
+            addr = addr_shifted;
+        }
+
+        // Page-boundary accesses
+        if (auto addr_ = (exception_addr + 0x40) >> HostPageBits; addr_ != addr_shifted && region.first <= addr_ && addr_ <= region.second) {
+            addr2 = addr_;
+        }
+    }
+
+    if (addr == 0 && addr2 == 0) {
+        // Not our problem
+        return EXCEPTION_CONTINUE_SEARCH;
+    }
+
+    LOG_ERROR(HW_Memory, "Accessing an unallocated region of a LargeVector at {:#x}; this shouldn't happen and is likely a Dynarmic error!", exception_addr);
+
+    // Commit this region
+    if (addr != 0) {
+        if (!CommitVectorPage(addr << HostPageBits, false)) {
+            return EXCEPTION_CONTINUE_SEARCH;
+        }
+    }
+    // Commit next region if needed
+    if (addr2 != 0) {
+        if (!CommitVectorPage(addr2 << HostPageBits, false)) {
+            return EXCEPTION_CONTINUE_SEARCH;
+        }
+    }
+
+    return EXCEPTION_CONTINUE_EXECUTION;
+}
+
+bool CommitVectorPage(uintptr_t addr, bool write) noexcept {
+    MEMORY_BASIC_INFORMATION info {};
+    auto res = VirtualQuery(reinterpret_cast<void*>(addr), &info, sizeof(info));
+    if (res == 0) {
+        LOG_CRITICAL(HW_Memory, "Failed to query large buffer region at {:#x} with error {}, will try committing anyway", addr, GetLastError());
+    } else if (info.State != MEM_RESERVE) {
+        LOG_ERROR(HW_Memory, "Tried to commit an unreserved large buffer region at {:#x} that is not mapped or is already committed (state {:#x})", addr, info.State);
+        return false;
+    }
+
+    auto perm = write ? PAGE_READWRITE : PAGE_READONLY;
+    void* res2 = VirtualAlloc(reinterpret_cast<LPVOID>(addr), HostPageSize, MEM_COMMIT, perm);
+    if (res2 == nullptr) {
+        LOG_ERROR(HW_Memory, "Failed to commit large buffer region at {:#x}, error {}", addr, GetLastError());
+        return false;
+    }
+
+    return true;
+}
+#endif
+
+void* AllocateMemoryPages(std::size_t size) noexcept {
+    if (auto page = HostPageSize; size % page != 0) {
+        LOG_WARNING(HW_Memory, "Allocating unaligned large vector with size {:#x}; aligning to {} page size", size, page);
+        size = AlignUp(size, page);
+    }
+
+#ifdef _WIN32
+    // We will never use this memory entirely so instead of committing it up front let's just reserve it and commit each page individually
+    void* base = VirtualAlloc(nullptr, size, MEM_RESERVE, PAGE_READWRITE);
+
+    if (base != nullptr) {
+        vector_regions.emplace_back(reinterpret_cast<u64>(base), reinterpret_cast<u64>(base) + size);
+
+        static std::once_flag flag;
+        std::call_once(flag, []() { AddVectoredExceptionHandler(1, FakePageFaultHandler); });
+    } else {
+        // Try committing everything instead??
+        LOG_WARNING(HW_Memory, "Failed to reserve large vector region with error {}, trying to commit instead..", GetLastError());
+        base = VirtualAlloc(nullptr, size, MEM_COMMIT, PAGE_READWRITE);
+    }
+    ASSERT_MSG(base, "Failed to reserve {:#x} sized region with error {}", size, GetLastError());
+#else
+    void* base = mmap(nullptr, size, PROT_READ, MAP_ANON | MAP_PRIVATE, -1, 0);
+    if (base == MAP_FAILED)
+        base = nullptr;
+    ASSERT_MSG(base, "Failed to allocate {:#x} sized region with error {}", size, strerror(errno));
+#endif
+    return base;
+}
+
+void FreeMemoryPages(void* base, [[maybe_unused]] std::size_t size) noexcept {
+    if (auto page = HostPageSize; size % page != 0) {
+        size = AlignUp(size, page);
+    }
+    if (!base)
+        return;
+#ifdef _WIN32
+    ASSERT(VirtualFree(base, 0, MEM_RELEASE));
+#else
+    ASSERT(munmap(base, size) == 0);
+#endif
+}
+
+} // namespace Common

src/common/sparse_large_vector.h

@@ -0,0 +1,181 @@
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+/* virtual_buffer.h */
+// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <atomic>
+#include <bit>
+#include <utility>
+#include <vector>
+
+#ifndef _WIN32
+#include <unistd.h>
+#include <sys/mman.h>
+#endif
+
+#include "common/assert.h"
+
+namespace Common {
+
+#ifdef _WIN32
+constexpr u64 HostPageSize = 0x1000;
+constexpr u64 HostPageBits = 12;
+constexpr u64 HostPageMask = ~(HostPageSize - 1);
+bool CommitVectorPage(uintptr_t addr, bool write) noexcept;
+#else
+const u64 HostPageSize = sysconf(_SC_PAGESIZE);
+const u64 HostPageBits = std::countr_zero(HostPageSize);
+const u64 HostPageMask = ~(HostPageSize - 1);
+#endif
+
+void* AllocateMemoryPages(std::size_t size) noexcept;
+void FreeMemoryPages(void* base, std::size_t size) noexcept;
+
+/// A large page-aligned buffer that has optimized memory usage for zero-writes.
+template <typename T>
+requires std::is_trivially_copyable_v<T>
+class SparseLargeVector final {
+public:
+    constexpr SparseLargeVector() = default;
+
+    explicit SparseLargeVector(std::size_t count) noexcept
+        : alloc_size{count * sizeof(T)}
+    {
+        base_ptr = static_cast<T*>(AllocateMemoryPages(alloc_size));
+
+        // each item in vector holds information for 64 pages
+        auto denom = HostPageSize * 64;
+        committed_pages = std::vector<std::atomic<u64>>((alloc_size + denom - 1) / denom);
+    }
+
+    ~SparseLargeVector() noexcept {
+        FreeMemoryPages(base_ptr, alloc_size);
+    }
+
+    SparseLargeVector(const SparseLargeVector&) = delete;
+    SparseLargeVector& operator=(const SparseLargeVector&) = delete;
+
+    SparseLargeVector(SparseLargeVector&& other) noexcept
+        : alloc_size{std::exchange(other.alloc_size, 0)}
+        , base_ptr{std::exchange(other.base_ptr, nullptr)}
+        , committed_pages{std::exchange(other.base_ptr, nullptr)}
+    {}
+
+    SparseLargeVector& operator=(SparseLargeVector&& other) noexcept {
+        alloc_size = std::exchange(other.alloc_size, 0);
+        base_ptr = std::exchange(other.base_ptr, nullptr);
+        committed_pages = std::exchange(other.base_ptr, nullptr);
+        return *this;
+    }
+
+    void ResizeAndClear(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 = static_cast<T*>(AllocateMemoryPages(alloc_size));
+
+            auto denom = HostPageSize * 64;
+            committed_pages = std::vector<std::atomic<u64>>((alloc_size + denom - 1) / denom);
+        }
+    }
+
+    /// Returns a pointer to the value of the requested index if that page has been allocated, or otherwise return nullptr.
+    T* GetNoFault(std::size_t index) const noexcept {
+        if (!IsCommittedPage(index)) {
+            return nullptr;
+        }
+        return &base_ptr[index];
+    }
+
+    /// Returns a reference to the value of the requested index and allocates memory if needed.
+    T& GetAndFault(std::size_t index) noexcept {
+        if (index > alloc_size / sizeof(T)) {
+            UNREACHABLE_MSG("Out of bounds RW access on SparseLargeVector @ {}", index);
+        }
+
+        if (!IsCommittedPage(index)) {
+            CommitPage(index);
+        }
+        return base_ptr[index];
+    }
+
+    /// Returns a reference to the value of the requested index if initialized, or will otherwise return a zero-initialized object.
+    const T& GetOrDefault(std::size_t index) const {
+#ifdef _WIN32
+        if (!IsCommittedPage(index)) {
+            return *reinterpret_cast<const T*>(&default_val);
+        }
+#endif
+        // On non-Windows, OS page table should optimize this by pointing to a zero page if unallocated.
+        return base_ptr[index];
+    }
+
+    void Set(std::size_t index, const T& value) noexcept {
+        if (index > alloc_size / sizeof(T)) {
+            LOG_CRITICAL(Common_Memory, "Out of bounds write on SparseLargeVector @ {}", index);
+            return;
+        }
+        if (!IsCommittedPage(index))
+            CommitPage(index);
+        base_ptr[index] = value;
+    }
+
+    void Zero(std::size_t index) noexcept {
+        if (!IsCommittedPage(index)) {
+            return;
+        }
+        // reinterpret_cast because C++ doesn't like memset'ing, but this should be valid
+        // because of std::is_trivially_copyable_v
+        std::memset(reinterpret_cast<void*>(&base_ptr[index]), 0, sizeof(T));
+    }
+
+    [[nodiscard]] constexpr const T& operator[](std::size_t index) const noexcept {
+        return GetOrDefault(index);
+    }
+
+    [[nodiscard]] constexpr const T* data() const noexcept {
+        return base_ptr;
+    }
+
+    [[nodiscard]] constexpr std::size_t size() const noexcept {
+        return alloc_size / sizeof(T);
+    }
+
+private:
+    [[nodiscard]] constexpr bool IsCommittedPage(std::size_t index) const noexcept {
+        if (index > alloc_size / sizeof(T)) {
+            LOG_CRITICAL(Common_Memory, "Out of bounds access on large vector @ {}", index);
+            return false;
+        }
+
+        auto page = (index * sizeof(T)) >> HostPageBits;
+        auto val = committed_pages[page >> 6].load(std::memory_order_acquire);
+        return (val >> (page & 63)) & 1;
+    }
+
+    constexpr void CommitPage(std::size_t index) noexcept {
+        auto page_index = (index * sizeof(T)) >> HostPageBits;
+        auto page = reinterpret_cast<uintptr_t>(base_ptr + index) & HostPageMask;
+#ifdef _WIN32
+        CommitVectorPage(page, true);
+#else
+        mprotect(reinterpret_cast<void*>(page), HostPageSize, PROT_READ | PROT_WRITE);
+#endif
+
+        committed_pages[page_index >> 6].fetch_or(1ULL << (page_index & 63), std::memory_order_release);
+    }
+
+    std::size_t alloc_size{};
+    T* base_ptr{};
+
+    std::vector<std::atomic<u64>> committed_pages{};
+#ifdef _WIN32
+    const std::array<u8, sizeof(T)> default_val{};
+#endif
+};
+
+} // namespace Common

src/common/virtual_buffer.cpp

@@ -1,44 +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
-
-#ifdef _WIN32
-#include <windows.h>
-#else
-#include <sys/mman.h>
-#endif
-
-#include "common/assert.h"
-#include "common/virtual_buffer.h"
-
-namespace Common {
-
-void* AllocateMemoryPages(std::size_t size) noexcept {
-#ifdef _WIN32
-    void* base = VirtualAlloc(nullptr, size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
-    if (base == nullptr) {
-        // Probably failing to reserve is less likely than failing to commit
-        base = VirtualAlloc(nullptr, size, MEM_COMMIT, PAGE_READWRITE);
-    }
-#else
-    void* base = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0);
-    if (base == MAP_FAILED)
-        base = nullptr;
-#endif
-    ASSERT(base);
-    return base;
-}
-
-void FreeMemoryPages(void* base, [[maybe_unused]] std::size_t size) noexcept {
-    if (!base)
-        return;
-#ifdef _WIN32
-    ASSERT(VirtualFree(base, 0, MEM_RELEASE));
-#else
-    ASSERT(munmap(base, size) == 0);
-#endif
-}
-
-} // namespace Common

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

src/core/arm/dynarmic/arm_dynarmic_32.cpp

@@ -175,7 +175,9 @@ void ArmDynarmic32::MakeJit(Common::PageTable* page_table) {
         constexpr size_t PageLog2Stride = 5;
         static_assert(1 << PageLog2Stride == sizeof(Common::PageTable::PageEntryData));
 
-        config.page_table = reinterpret_cast<std::array<std::uint8_t*, NumPageTableEntries>*>(page_table->entries.data());
+        // Dynarmic will not write to the page table, const_cast is safe here
+        config.page_table = reinterpret_cast<std::array<std::uint8_t*, NumPageTableEntries>*>(
+            const_cast<Common::PageTable::PageEntryData*>(page_table->entries.data()));
         config.page_table_pointer_mask_bits = Common::PageTable::ATTRIBUTE_BITS;
         config.page_table_log2_stride = PageLog2Stride;
         config.absolute_offset_page_table = true;

src/core/arm/dynarmic/arm_dynarmic_64.cpp

@@ -214,7 +214,9 @@ void ArmDynarmic64::MakeJit(Common::PageTable* page_table, std::size_t address_s
         constexpr size_t PageLog2Stride = 5;
         static_assert(1 << PageLog2Stride == sizeof(Common::PageTable::PageEntryData));
 
-        config.page_table = reinterpret_cast<void**>(page_table->entries.data());
+        // Dynarmic will not write to the page table, const_cast is safe here
+        config.page_table = reinterpret_cast<void**>(
+            const_cast<Common::PageTable::PageEntryData*>(page_table->entries.data()));
         config.page_table_address_space_bits = std::uint32_t(address_space_bits);
         config.page_table_pointer_mask_bits = Common::PageTable::ATTRIBUTE_BITS;
         config.page_table_log2_stride = PageLog2Stride;

src/core/device_memory_manager.h

@@ -18,7 +18,7 @@
 #include "common/common_types.h"
 #include "common/range_mutex.h"
 #include "common/scratch_buffer.h"
-#include "common/virtual_buffer.h"
+#include "common/sparse_large_vector.h"
 
 namespace Core {
 
@@ -178,8 +178,8 @@ private:
         u32 continuity_tracker;
         u32 compressed_physical_ptr;
     };
-    Common::VirtualBuffer<u32> compressed_device_addr;
-    Common::VirtualBuffer<TrackedEntry> tracked_entries;
+    Common::SparseLargeVector<u32> compressed_device_addr;
+    Common::SparseLargeVector<TrackedEntry> tracked_entries;
 
     // Process memory interfaces
 
@@ -201,7 +201,7 @@ private:
     }
 
     void InsertCPUBacking(size_t page_index, VAddr address, Asid asid) {
-        tracked_entries[page_index].cpu_backing_address = address | (asid.id << asid_start_bit);
+        tracked_entries.GetAndFault(page_index).cpu_backing_address = address | (asid.id << asid_start_bit);
     }
 
     std::array<TranslationEntry, 4> t_slot{};

src/core/device_memory_manager.inc

@@ -179,14 +179,17 @@ DeviceMemoryManager<Traits>::DeviceMemoryManager(const DeviceMemory& device_memo
     cached_pages = std::make_unique<CachedPages>();
 
     const size_t total_virtual = device_as_size >> Memory::YUZU_PAGEBITS;
+
+    auto virtual_entry = TrackedEntry {};
+    virtual_entry.compressed_physical_ptr = 0;
+    virtual_entry.continuity_tracker = 1;
+    virtual_entry.cpu_backing_address = 0;
     for (size_t i = 0; i < total_virtual; i++) {
-        tracked_entries[i].compressed_physical_ptr = 0;
-        tracked_entries[i].continuity_tracker = 1;
-        tracked_entries[i].cpu_backing_address = 0;
+        tracked_entries.Set(i, virtual_entry);
     }
     const size_t total_phys = 1ULL << ((Settings::values.memory_layout_mode.GetValue() == Settings::MemoryLayout::Memory_4Gb ? physical_min_bits : physical_max_bits) - Memory::YUZU_PAGEBITS);
     for (size_t i = 0; i < total_phys; i++) {
-        compressed_device_addr[i] = 0;
+        compressed_device_addr.Zero(i);
     }
 }
 
@@ -224,22 +227,24 @@ void DeviceMemoryManager<Traits>::Map(DAddr address, VAddr virtual_address, size
         const VAddr new_vaddress = virtual_address + i * Memory::YUZU_PAGESIZE;
         auto* ptr = process_memory->GetPointerSilent(Common::ProcessAddress(new_vaddress));
         if (ptr == nullptr) [[unlikely]] {
-            tracked_entries[start_page_d + i].compressed_physical_ptr = 0;
+            if (auto v = tracked_entries.GetNoFault(start_page_d + i); v) {
+                v->compressed_physical_ptr = 0;
+            }
             continue;
         }
         auto phys_addr = static_cast<u32>(GetRawPhysicalAddr(ptr) >> Memory::YUZU_PAGEBITS) + 1U;
-        tracked_entries[start_page_d + i].compressed_physical_ptr = phys_addr;
+        tracked_entries.GetAndFault(start_page_d + i).compressed_physical_ptr = phys_addr;
         InsertCPUBacking(start_page_d + i, new_vaddress, asid);
         const u32 base_dev = compressed_device_addr[phys_addr - 1U];
         const u32 new_dev = static_cast<u32>(start_page_d + i);
         if (base_dev == 0) [[likely]] {
-            compressed_device_addr[phys_addr - 1U] = new_dev;
+            compressed_device_addr.GetAndFault(phys_addr - 1U) = new_dev;
             continue;
         }
         u32 start_id = base_dev & MULTI_MASK;
         if ((base_dev >> MULTI_FLAG_BITS) == 0) {
             start_id = impl->multi_dev_address.Register(base_dev);
-            compressed_device_addr[phys_addr - 1U] = MULTI_FLAG | start_id;
+            compressed_device_addr.GetAndFault(phys_addr - 1U) = MULTI_FLAG | start_id;
         }
         impl->multi_dev_address.Register(new_dev, start_id);
     }
@@ -256,23 +261,24 @@ void DeviceMemoryManager<Traits>::Unmap(DAddr address, size_t size) {
     device_inter->InvalidateRegion(address, size);
     std::scoped_lock lk(mapping_guard);
     for (size_t i = 0; i < num_pages; i++) {
-        auto phys_addr = tracked_entries[start_page_d + i].compressed_physical_ptr;
-        tracked_entries[start_page_d + i].compressed_physical_ptr = 0;
-        tracked_entries[start_page_d + i].cpu_backing_address = 0;
+        auto& entry = tracked_entries.GetAndFault(start_page_d + i);
+        auto phys_addr = entry.compressed_physical_ptr;
+        entry.compressed_physical_ptr = 0;
+        entry.cpu_backing_address = 0;
         if (phys_addr != 0) [[likely]] {
             const u32 base_dev = compressed_device_addr[phys_addr - 1U];
             if ((base_dev >> MULTI_FLAG_BITS) == 0) [[likely]] {
-                compressed_device_addr[phys_addr - 1] = 0;
+                compressed_device_addr.Zero(phys_addr - 1);
                 continue;
             }
             const auto [more_entries, new_start] = impl->multi_dev_address.Unregister(
                 static_cast<u32>(start_page_d + i), base_dev & MULTI_MASK);
             if (!more_entries) {
-                compressed_device_addr[phys_addr - 1] =
-                    impl->multi_dev_address.ReleaseEntry(new_start);
+                compressed_device_addr.Set(phys_addr - 1,
+                    impl->multi_dev_address.ReleaseEntry(new_start));
                 continue;
             }
-            compressed_device_addr[phys_addr - 1] = new_start | MULTI_FLAG;
+            compressed_device_addr.Set(phys_addr - 1, new_start | MULTI_FLAG);
         }
     }
     t_slot = {};
@@ -296,7 +302,7 @@ void DeviceMemoryManager<Traits>::TrackContinuityImpl(DAddr address, VAddr virtu
             page_count = 1;
         }
         last_ptr = new_ptr;
-        tracked_entries[start_page_d + index].continuity_tracker = static_cast<u32>(page_count);
+        tracked_entries.GetAndFault(start_page_d + index).continuity_tracker = static_cast<u32>(page_count);
     }
 }
 template <typename Traits>

src/core/memory.cpp

@@ -417,7 +417,7 @@ struct Memory::Impl {
                     // Page is already marked.
                     break;
                 case Common::PageType::Memory:
-                    current_page_table->entries[vaddr >> YUZU_PAGEBITS].ptr.Store(0, Common::PageType::DebugMemory);
+                    current_page_table->entries.GetAndFault(vaddr >> YUZU_PAGEBITS).ptr.Store(0, Common::PageType::DebugMemory);
                     break;
                 default:
                     UNREACHABLE();
@@ -434,7 +434,7 @@ struct Memory::Impl {
                     break;
                 case Common::PageType::DebugMemory: {
                     u8* const pointer = GetPointerFromDebugMemory(vaddr & ~YUZU_PAGEMASK);
-                    current_page_table->entries[vaddr >> YUZU_PAGEBITS].ptr.Store(uintptr_t(pointer) - (vaddr & ~YUZU_PAGEMASK), Common::PageType::Memory);
+                    current_page_table->entries.GetAndFault(vaddr >> YUZU_PAGEBITS).ptr.Store(uintptr_t(pointer) - (vaddr & ~YUZU_PAGEMASK), Common::PageType::Memory);
                     break;
                 }
                 default:
@@ -477,7 +477,7 @@ struct Memory::Impl {
                     break;
                 case Common::PageType::DebugMemory:
                 case Common::PageType::Memory:
-                    current_page_table->entries[vaddr >> YUZU_PAGEBITS].ptr.Store(0, Common::PageType::RasterizerCachedMemory);
+                    current_page_table->entries.GetAndFault(vaddr >> YUZU_PAGEBITS).ptr.Store(0, Common::PageType::RasterizerCachedMemory);
                     break;
                 case Common::PageType::RasterizerCachedMemory:
                     // There can be more than one GPU region mapped per CPU region, so it's common
@@ -503,9 +503,9 @@ struct Memory::Impl {
                         // It's possible that this function has been called while updating the
                         // pagetable after unmapping a VMA. In that case the underlying VMA will no
                         // longer exist, and we should just leave the pagetable entry blank.
-                        current_page_table->entries[vaddr >> YUZU_PAGEBITS].ptr.Store(0, Common::PageType::Unmapped);
+                        current_page_table->entries.GetAndFault(vaddr >> YUZU_PAGEBITS).ptr.Store(0, Common::PageType::Unmapped);
                     } else {
-                        current_page_table->entries[vaddr >> YUZU_PAGEBITS].ptr.Store(uintptr_t(pointer) - (vaddr & ~YUZU_PAGEMASK), Common::PageType::Memory);
+                        current_page_table->entries.GetAndFault(vaddr >> YUZU_PAGEBITS).ptr.Store(uintptr_t(pointer) - (vaddr & ~YUZU_PAGEMASK), Common::PageType::Memory);
                     }
                     break;
                 }
@@ -540,9 +540,8 @@ struct Memory::Impl {
                        "Mapping memory page without a pointer @ {:016x}", base * YUZU_PAGESIZE);
 
             while (base != end) {
-                page_table.entries[base].ptr.Store(0, type);
-                page_table.entries[base].addr = 0;
-                page_table.entries[base].block = 0;
+                // TODO: add a ZeroRegion function
+                page_table.entries.Zero(base);
                 base += 1;
             }
         } else {
@@ -550,9 +549,11 @@ struct Memory::Impl {
             while (base != end) {
                 auto host_ptr = uintptr_t(system.DeviceMemory().GetPointer<u8>(target)) - (base << YUZU_PAGEBITS);
                 auto backing = GetInteger(target) - (base << YUZU_PAGEBITS);
-                page_table.entries[base].ptr.Store(host_ptr, type);
-                page_table.entries[base].addr = backing;
-                page_table.entries[base].block = orig_base << YUZU_PAGEBITS;
+
+                auto& entry = page_table.entries.GetAndFault(base);
+                entry.ptr.Store(host_ptr, type);
+                entry.addr = backing;
+                entry.block = orig_base << YUZU_PAGEBITS;
 
                 ASSERT_MSG(page_table.entries[base].ptr.Pointer(),
                            "memory mapping base yield a nullptr within the table");

src/video_core/memory_manager.cpp

@@ -46,8 +46,8 @@ MemoryManager::MemoryManager(Core::System& system_, MaxwellDeviceMemoryManager&
     page_table_mask = page_table_size - 1;
     big_page_table_mask = big_page_table_size - 1;
 
+    big_page_table_dev.ResizeAndClear(big_page_table_size);
     big_entries.resize(big_page_table_size / 32, 0);
-    big_page_table_dev.resize(big_page_table_size);
     big_page_continuous.resize(big_page_table_size / continuous_bits, 0);
     entries.resize(page_table_size / 32, 0);
 }
@@ -143,7 +143,7 @@ GPUVAddr MemoryManager::BigPageTableOp(GPUVAddr gpu_addr, [[maybe_unused]] DAddr
             const DAddr current_dev_addr = dev_addr + offset;
             const auto index = PageEntryIndex(current_gpu_addr, true);
             const u32 sub_value = static_cast<u32>(current_dev_addr >> cpu_page_bits);
-            big_page_table_dev[index] = sub_value;
+            big_page_table_dev.Set(index, sub_value);
             const bool is_continuous = ([&] {
                 uintptr_t base_ptr{
                     reinterpret_cast<uintptr_t>(memory.GetPointer<u8>(current_dev_addr))};

src/video_core/memory_manager.h

@@ -17,7 +17,7 @@
 #include "common/multi_level_page_table.h"
 #include "common/range_map.h"
 #include "common/scratch_buffer.h"
-#include "common/virtual_buffer.h"
+#include "common/sparse_large_vector.h"
 #include "video_core/invalidation_accumulator.h"
 #include "video_core/cache_types.h"
 #include "video_core/host1x/gpu_device_memory_manager.h"
@@ -214,7 +214,7 @@ private:
 
     Common::MultiLevelPageTable<u32> page_table;
     Common::RangeMap<GPUVAddr, PTEKind> kind_map;
-    Common::VirtualBuffer<u32> big_page_table_dev;
+    Common::SparseLargeVector<u32> big_page_table_dev;
 
     std::vector<u64> big_page_continuous;
     boost::container::small_vector<std::pair<DAddr, std::size_t>, 32> page_stash{};