Merge pull request #9604 from liamwhite/pt

kernel: KPageTable: update

6 files changed, 477 insertions, 215 deletions

diff --git a/src/core/hle/kernel/k_code_memory.cpp b/src/core/hle/kernel/k_code_memory.cpp
index d9da1e600..884eba001 100644
--- a/src/core/hle/kernel/k_code_memory.cpp
+++ b/src/core/hle/kernel/k_code_memory.cpp
@@ -74,7 +74,7 @@ Result KCodeMemory::Map(VAddr address, size_t size) {
     R_UNLESS(!m_is_mapped, ResultInvalidState);
 
     // Map the memory.
-    R_TRY(kernel.CurrentProcess()->PageTable().MapPages(
+    R_TRY(kernel.CurrentProcess()->PageTable().MapPageGroup(
         address, *m_page_group, KMemoryState::CodeOut, KMemoryPermission::UserReadWrite));
 
     // Mark ourselves as mapped.
@@ -91,8 +91,8 @@ Result KCodeMemory::Unmap(VAddr address, size_t size) {
     KScopedLightLock lk(m_lock);
 
     // Unmap the memory.
-    R_TRY(kernel.CurrentProcess()->PageTable().UnmapPages(address, *m_page_group,
-                                                          KMemoryState::CodeOut));
+    R_TRY(kernel.CurrentProcess()->PageTable().UnmapPageGroup(address, *m_page_group,
+                                                              KMemoryState::CodeOut));
 
     // Mark ourselves as unmapped.
     m_is_mapped = false;
@@ -125,8 +125,8 @@ Result KCodeMemory::MapToOwner(VAddr address, size_t size, Svc::MemoryPermission
     }
 
     // Map the memory.
-    R_TRY(
-        m_owner->PageTable().MapPages(address, *m_page_group, KMemoryState::GeneratedCode, k_perm));
+    R_TRY(m_owner->PageTable().MapPageGroup(address, *m_page_group, KMemoryState::GeneratedCode,
+                                            k_perm));
 
     // Mark ourselves as mapped.
     m_is_owner_mapped = true;
@@ -142,7 +142,7 @@ Result KCodeMemory::UnmapFromOwner(VAddr address, size_t size) {
     KScopedLightLock lk(m_lock);
 
     // Unmap the memory.
-    R_TRY(m_owner->PageTable().UnmapPages(address, *m_page_group, KMemoryState::GeneratedCode));
+    R_TRY(m_owner->PageTable().UnmapPageGroup(address, *m_page_group, KMemoryState::GeneratedCode));
 
     // Mark ourselves as unmapped.
     m_is_owner_mapped = false;
diff --git a/src/core/hle/kernel/k_page_table.cpp b/src/core/hle/kernel/k_page_table.cpp
index 9c7ac22dc..fbd28f5f3 100644
--- a/src/core/hle/kernel/k_page_table.cpp
+++ b/src/core/hle/kernel/k_page_table.cpp
@@ -435,6 +435,9 @@ Result KPageTable::MapCodeMemory(VAddr dst_address, VAddr src_address, size_t si
         KPageGroup pg{m_kernel, m_block_info_manager};
         AddRegionToPages(src_address, num_pages, pg);
 
+        // We're going to perform an update, so create a helper.
+        KScopedPageTableUpdater updater(this);
+
         // Reprotect the source as kernel-read/not mapped.
         const auto new_perm = static_cast<KMemoryPermission>(KMemoryPermission::KernelRead |
                                                              KMemoryPermission::NotMapped);
@@ -447,7 +450,10 @@ Result KPageTable::MapCodeMemory(VAddr dst_address, VAddr src_address, size_t si
         });
 
         // Map the alias pages.
-        R_TRY(MapPages(dst_address, pg, new_perm));
+        const KPageProperties dst_properties = {new_perm, false, false,
+                                                DisableMergeAttribute::DisableHead};
+        R_TRY(
+            this->MapPageGroupImpl(updater.GetPageList(), dst_address, pg, dst_properties, false));
 
         // We successfully mapped the alias pages, so we don't need to unprotect the src pages on
         // failure.
@@ -1881,7 +1887,8 @@ Result KPageTable::UnmapPhysicalMemory(VAddr address, size_t size) {
     R_SUCCEED();
 }
 
-Result KPageTable::MapMemory(VAddr dst_address, VAddr src_address, size_t size) {
+Result KPageTable::MapMemory(KProcessAddress dst_address, KProcessAddress src_address,
+                             size_t size) {
     // Lock the table.
     KScopedLightLock lk(m_general_lock);
 
@@ -1902,53 +1909,73 @@ Result KPageTable::MapMemory(VAddr dst_address, VAddr src_address, size_t size)
                                  KMemoryAttribute::None));
 
     // Create an update allocator for the source.
-    Result src_allocator_result{ResultSuccess};
+    Result src_allocator_result;
     KMemoryBlockManagerUpdateAllocator src_allocator(std::addressof(src_allocator_result),
                                                      m_memory_block_slab_manager,
                                                      num_src_allocator_blocks);
     R_TRY(src_allocator_result);
 
     // Create an update allocator for the destination.
-    Result dst_allocator_result{ResultSuccess};
+    Result dst_allocator_result;
     KMemoryBlockManagerUpdateAllocator dst_allocator(std::addressof(dst_allocator_result),
                                                      m_memory_block_slab_manager,
                                                      num_dst_allocator_blocks);
     R_TRY(dst_allocator_result);
 
     // Map the memory.
-    KPageGroup page_linked_list{m_kernel, m_block_info_manager};
-    const size_t num_pages{size / PageSize};
-    const KMemoryPermission new_src_perm = static_cast<KMemoryPermission>(
-        KMemoryPermission::KernelRead | KMemoryPermission::NotMapped);
-    const KMemoryAttribute new_src_attr = KMemoryAttribute::Locked;
-
-    AddRegionToPages(src_address, num_pages, page_linked_list);
     {
+        // Determine the number of pages being operated on.
+        const size_t num_pages = size / PageSize;
+
+        // Create page groups for the memory being unmapped.
+        KPageGroup pg{m_kernel, m_block_info_manager};
+
+        // Create the page group representing the source.
+        R_TRY(this->MakePageGroup(pg, src_address, num_pages));
+
+        // We're going to perform an update, so create a helper.
+        KScopedPageTableUpdater updater(this);
+
         // Reprotect the source as kernel-read/not mapped.
-        auto block_guard = detail::ScopeExit([&] {
-            Operate(src_address, num_pages, KMemoryPermission::UserReadWrite,
-                    OperationType::ChangePermissions);
-        });
-        R_TRY(Operate(src_address, num_pages, new_src_perm, OperationType::ChangePermissions));
-        R_TRY(MapPages(dst_address, page_linked_list, KMemoryPermission::UserReadWrite));
+        const KMemoryPermission new_src_perm = static_cast<KMemoryPermission>(
+            KMemoryPermission::KernelRead | KMemoryPermission::NotMapped);
+        const KMemoryAttribute new_src_attr = KMemoryAttribute::Locked;
+        const KPageProperties src_properties = {new_src_perm, false, false,
+                                                DisableMergeAttribute::DisableHeadBodyTail};
+        R_TRY(this->Operate(src_address, num_pages, src_properties.perm,
+                            OperationType::ChangePermissions));
 
-        block_guard.Cancel();
-    }
+        // Ensure that we unprotect the source pages on failure.
+        ON_RESULT_FAILURE {
+            const KPageProperties unprotect_properties = {
+                KMemoryPermission::UserReadWrite, false, false,
+                DisableMergeAttribute::EnableHeadBodyTail};
+            ASSERT(this->Operate(src_address, num_pages, unprotect_properties.perm,
+                                 OperationType::ChangePermissions) == ResultSuccess);
+        };
 
-    // Apply the memory block updates.
-    m_memory_block_manager.Update(std::addressof(src_allocator), src_address, num_pages, src_state,
-                                  new_src_perm, new_src_attr,
-                                  KMemoryBlockDisableMergeAttribute::Locked,
-                                  KMemoryBlockDisableMergeAttribute::None);
-    m_memory_block_manager.Update(std::addressof(dst_allocator), dst_address, num_pages,
-                                  KMemoryState::Stack, KMemoryPermission::UserReadWrite,
-                                  KMemoryAttribute::None, KMemoryBlockDisableMergeAttribute::Normal,
-                                  KMemoryBlockDisableMergeAttribute::None);
+        // Map the alias pages.
+        const KPageProperties dst_map_properties = {KMemoryPermission::UserReadWrite, false, false,
+                                                    DisableMergeAttribute::DisableHead};
+        R_TRY(this->MapPageGroupImpl(updater.GetPageList(), dst_address, pg, dst_map_properties,
+                                     false));
+
+        // Apply the memory block updates.
+        m_memory_block_manager.Update(std::addressof(src_allocator), src_address, num_pages,
+                                      src_state, new_src_perm, new_src_attr,
+                                      KMemoryBlockDisableMergeAttribute::Locked,
+                                      KMemoryBlockDisableMergeAttribute::None);
+        m_memory_block_manager.Update(
+            std::addressof(dst_allocator), dst_address, num_pages, KMemoryState::Stack,
+            KMemoryPermission::UserReadWrite, KMemoryAttribute::None,
+            KMemoryBlockDisableMergeAttribute::Normal, KMemoryBlockDisableMergeAttribute::None);
+    }
 
     R_SUCCEED();
 }
 
-Result KPageTable::UnmapMemory(VAddr dst_address, VAddr src_address, size_t size) {
+Result KPageTable::UnmapMemory(KProcessAddress dst_address, KProcessAddress src_address,
+                               size_t size) {
     // Lock the table.
     KScopedLightLock lk(m_general_lock);
 
@@ -1970,108 +1997,208 @@ Result KPageTable::UnmapMemory(VAddr dst_address, VAddr src_address, size_t size
         KMemoryPermission::None, KMemoryAttribute::All, KMemoryAttribute::None));
 
     // Create an update allocator for the source.
-    Result src_allocator_result{ResultSuccess};
+    Result src_allocator_result;
     KMemoryBlockManagerUpdateAllocator src_allocator(std::addressof(src_allocator_result),
                                                      m_memory_block_slab_manager,
                                                      num_src_allocator_blocks);
     R_TRY(src_allocator_result);
 
     // Create an update allocator for the destination.
-    Result dst_allocator_result{ResultSuccess};
+    Result dst_allocator_result;
     KMemoryBlockManagerUpdateAllocator dst_allocator(std::addressof(dst_allocator_result),
                                                      m_memory_block_slab_manager,
                                                      num_dst_allocator_blocks);
     R_TRY(dst_allocator_result);
 
-    KPageGroup src_pages{m_kernel, m_block_info_manager};
-    KPageGroup dst_pages{m_kernel, m_block_info_manager};
-    const size_t num_pages{size / PageSize};
+    // Unmap the memory.
+    {
+        // Determine the number of pages being operated on.
+        const size_t num_pages = size / PageSize;
 
-    AddRegionToPages(src_address, num_pages, src_pages);
-    AddRegionToPages(dst_address, num_pages, dst_pages);
+        // Create page groups for the memory being unmapped.
+        KPageGroup pg{m_kernel, m_block_info_manager};
 
-    R_UNLESS(dst_pages.IsEquivalentTo(src_pages), ResultInvalidMemoryRegion);
+        // Create the page group representing the destination.
+        R_TRY(this->MakePageGroup(pg, dst_address, num_pages));
 
-    {
-        auto block_guard = detail::ScopeExit([&] { MapPages(dst_address, dst_pages, dst_perm); });
+        // Ensure the page group is the valid for the source.
+        R_UNLESS(this->IsValidPageGroup(pg, src_address, num_pages), ResultInvalidMemoryRegion);
 
-        R_TRY(Operate(dst_address, num_pages, KMemoryPermission::None, OperationType::Unmap));
-        R_TRY(Operate(src_address, num_pages, KMemoryPermission::UserReadWrite,
-                      OperationType::ChangePermissions));
+        // We're going to perform an update, so create a helper.
+        KScopedPageTableUpdater updater(this);
 
-        block_guard.Cancel();
-    }
+        // Unmap the aliased copy of the pages.
+        const KPageProperties dst_unmap_properties = {KMemoryPermission::None, false, false,
+                                                      DisableMergeAttribute::None};
+        R_TRY(
+            this->Operate(dst_address, num_pages, dst_unmap_properties.perm, OperationType::Unmap));
+
+        // Ensure that we re-map the aliased pages on failure.
+        ON_RESULT_FAILURE {
+            this->RemapPageGroup(updater.GetPageList(), dst_address, size, pg);
+        };
 
-    // Apply the memory block updates.
-    m_memory_block_manager.Update(std::addressof(src_allocator), src_address, num_pages, src_state,
-                                  KMemoryPermission::UserReadWrite, KMemoryAttribute::None,
-                                  KMemoryBlockDisableMergeAttribute::None,
-                                  KMemoryBlockDisableMergeAttribute::Locked);
-    m_memory_block_manager.Update(std::addressof(dst_allocator), dst_address, num_pages,
-                                  KMemoryState::None, KMemoryPermission::None,
-                                  KMemoryAttribute::None, KMemoryBlockDisableMergeAttribute::None,
-                                  KMemoryBlockDisableMergeAttribute::Normal);
+        // Try to set the permissions for the source pages back to what they should be.
+        const KPageProperties src_properties = {KMemoryPermission::UserReadWrite, false, false,
+                                                DisableMergeAttribute::EnableAndMergeHeadBodyTail};
+        R_TRY(this->Operate(src_address, num_pages, src_properties.perm,
+                            OperationType::ChangePermissions));
+
+        // Apply the memory block updates.
+        m_memory_block_manager.Update(
+            std::addressof(src_allocator), src_address, num_pages, src_state,
+            KMemoryPermission::UserReadWrite, KMemoryAttribute::None,
+            KMemoryBlockDisableMergeAttribute::None, KMemoryBlockDisableMergeAttribute::Locked);
+        m_memory_block_manager.Update(
+            std::addressof(dst_allocator), dst_address, num_pages, KMemoryState::None,
+            KMemoryPermission::None, KMemoryAttribute::None,
+            KMemoryBlockDisableMergeAttribute::None, KMemoryBlockDisableMergeAttribute::Normal);
+    }
 
     R_SUCCEED();
 }
 
-Result KPageTable::MapPages(VAddr addr, const KPageGroup& page_linked_list,
-                            KMemoryPermission perm) {
+Result KPageTable::AllocateAndMapPagesImpl(PageLinkedList* page_list, KProcessAddress address,
+                                           size_t num_pages, KMemoryPermission perm) {
     ASSERT(this->IsLockedByCurrentThread());
 
-    VAddr cur_addr{addr};
+    // Create a page group to hold the pages we allocate.
+    KPageGroup pg{m_kernel, m_block_info_manager};
 
-    for (const auto& node : page_linked_list) {
-        if (const auto result{
-                Operate(cur_addr, node.GetNumPages(), perm, OperationType::Map, node.GetAddress())};
-            result.IsError()) {
-            const size_t num_pages{(addr - cur_addr) / PageSize};
+    // Allocate the pages.
+    R_TRY(
+        m_kernel.MemoryManager().AllocateAndOpen(std::addressof(pg), num_pages, m_allocate_option));
 
-            ASSERT(Operate(addr, num_pages, KMemoryPermission::None, OperationType::Unmap)
-                       .IsSuccess());
+    // Ensure that the page group is closed when we're done working with it.
+    SCOPE_EXIT({ pg.Close(); });
 
-            R_RETURN(result);
+    // Clear all pages.
+    for (const auto& it : pg) {
+        std::memset(m_system.DeviceMemory().GetPointer<void>(it.GetAddress()), m_heap_fill_value,
+                    it.GetSize());
+    }
+
+    // Map the pages.
+    R_RETURN(this->Operate(address, num_pages, pg, OperationType::MapGroup));
+}
+
+Result KPageTable::MapPageGroupImpl(PageLinkedList* page_list, KProcessAddress address,
+                                    const KPageGroup& pg, const KPageProperties properties,
+                                    bool reuse_ll) {
+    ASSERT(this->IsLockedByCurrentThread());
+
+    // Note the current address, so that we can iterate.
+    const KProcessAddress start_address = address;
+    KProcessAddress cur_address = address;
+
+    // Ensure that we clean up on failure.
+    ON_RESULT_FAILURE {
+        ASSERT(!reuse_ll);
+        if (cur_address != start_address) {
+            const KPageProperties unmap_properties = {KMemoryPermission::None, false, false,
+                                                      DisableMergeAttribute::None};
+            ASSERT(this->Operate(start_address, (cur_address - start_address) / PageSize,
+                                 unmap_properties.perm, OperationType::Unmap) == ResultSuccess);
         }
+    };
 
-        cur_addr += node.GetNumPages() * PageSize;
+    // Iterate, mapping all pages in the group.
+    for (const auto& block : pg) {
+        // Map and advance.
+        const KPageProperties cur_properties =
+            (cur_address == start_address)
+                ? properties
+                : KPageProperties{properties.perm, properties.io, properties.uncached,
+                                  DisableMergeAttribute::None};
+        this->Operate(cur_address, block.GetNumPages(), cur_properties.perm, OperationType::Map,
+                      block.GetAddress());
+        cur_address += block.GetSize();
     }
 
+    // We succeeded!
     R_SUCCEED();
 }
 
-Result KPageTable::MapPages(VAddr address, KPageGroup& page_linked_list, KMemoryState state,
-                            KMemoryPermission perm) {
-    // Check that the map is in range.
-    const size_t num_pages{page_linked_list.GetNumPages()};
-    const size_t size{num_pages * PageSize};
-    R_UNLESS(this->CanContain(address, size, state), ResultInvalidCurrentMemory);
+void KPageTable::RemapPageGroup(PageLinkedList* page_list, KProcessAddress address, size_t size,
+                                const KPageGroup& pg) {
+    ASSERT(this->IsLockedByCurrentThread());
 
-    // Lock the table.
-    KScopedLightLock lk(m_general_lock);
+    // Note the current address, so that we can iterate.
+    const KProcessAddress start_address = address;
+    const KProcessAddress last_address = start_address + size - 1;
+    const KProcessAddress end_address = last_address + 1;
 
-    // Check the memory state.
-    R_TRY(this->CheckMemoryState(address, size, KMemoryState::All, KMemoryState::Free,
-                                 KMemoryPermission::None, KMemoryPermission::None,
-                                 KMemoryAttribute::None, KMemoryAttribute::None));
+    // Iterate over the memory.
+    auto pg_it = pg.begin();
+    ASSERT(pg_it != pg.end());
 
-    // Create an update allocator.
-    Result allocator_result{ResultSuccess};
-    KMemoryBlockManagerUpdateAllocator allocator(std::addressof(allocator_result),
-                                                 m_memory_block_slab_manager);
+    KPhysicalAddress pg_phys_addr = pg_it->GetAddress();
+    size_t pg_pages = pg_it->GetNumPages();
 
-    // Map the pages.
-    R_TRY(MapPages(address, page_linked_list, perm));
+    auto it = m_memory_block_manager.FindIterator(start_address);
+    while (true) {
+        // Check that the iterator is valid.
+        ASSERT(it != m_memory_block_manager.end());
 
-    // Update the blocks.
-    m_memory_block_manager.Update(std::addressof(allocator), address, num_pages, state, perm,
-                                  KMemoryAttribute::None, KMemoryBlockDisableMergeAttribute::Normal,
-                                  KMemoryBlockDisableMergeAttribute::None);
+        // Get the memory info.
+        const KMemoryInfo info = it->GetMemoryInfo();
 
-    R_SUCCEED();
+        // Determine the range to map.
+        KProcessAddress map_address = std::max(info.GetAddress(), start_address);
+        const KProcessAddress map_end_address = std::min(info.GetEndAddress(), end_address);
+        ASSERT(map_end_address != map_address);
+
+        // Determine if we should disable head merge.
+        const bool disable_head_merge =
+            info.GetAddress() >= start_address &&
+            True(info.GetDisableMergeAttribute() & KMemoryBlockDisableMergeAttribute::Normal);
+        const KPageProperties map_properties = {
+            info.GetPermission(), false, false,
+            disable_head_merge ? DisableMergeAttribute::DisableHead : DisableMergeAttribute::None};
+
+        // While we have pages to map, map them.
+        size_t map_pages = (map_end_address - map_address) / PageSize;
+        while (map_pages > 0) {
+            // Check if we're at the end of the physical block.
+            if (pg_pages == 0) {
+                // Ensure there are more pages to map.
+                ASSERT(pg_it != pg.end());
+
+                // Advance our physical block.
+                ++pg_it;
+                pg_phys_addr = pg_it->GetAddress();
+                pg_pages = pg_it->GetNumPages();
+            }
+
+            // Map whatever we can.
+            const size_t cur_pages = std::min(pg_pages, map_pages);
+            ASSERT(this->Operate(map_address, map_pages, map_properties.perm, OperationType::Map,
+                                 pg_phys_addr) == ResultSuccess);
+
+            // Advance.
+            map_address += cur_pages * PageSize;
+            map_pages -= cur_pages;
+
+            pg_phys_addr += cur_pages * PageSize;
+            pg_pages -= cur_pages;
+        }
+
+        // Check if we're done.
+        if (last_address <= info.GetLastAddress()) {
+            break;
+        }
+
+        // Advance.
+        ++it;
+    }
+
+    // Check that we re-mapped precisely the page group.
+    ASSERT((++pg_it) == pg.end());
 }
 
-Result KPageTable::MapPages(VAddr* out_addr, size_t num_pages, size_t alignment, PAddr phys_addr,
-                            bool is_pa_valid, VAddr region_start, size_t region_num_pages,
+Result KPageTable::MapPages(KProcessAddress* out_addr, size_t num_pages, size_t alignment,
+                            KPhysicalAddress phys_addr, bool is_pa_valid,
+                            KProcessAddress region_start, size_t region_num_pages,
                             KMemoryState state, KMemoryPermission perm) {
     ASSERT(Common::IsAligned(alignment, PageSize) && alignment >= PageSize);
 
@@ -2084,26 +2211,30 @@ Result KPageTable::MapPages(VAddr* out_addr, size_t num_pages, size_t alignment,
     KScopedLightLock lk(m_general_lock);
 
     // Find a random address to map at.
-    VAddr addr = this->FindFreeArea(region_start, region_num_pages, num_pages, alignment, 0,
-                                    this->GetNumGuardPages());
+    KProcessAddress addr = this->FindFreeArea(region_start, region_num_pages, num_pages, alignment,
+                                              0, this->GetNumGuardPages());
     R_UNLESS(addr != 0, ResultOutOfMemory);
     ASSERT(Common::IsAligned(addr, alignment));
     ASSERT(this->CanContain(addr, num_pages * PageSize, state));
     ASSERT(this->CheckMemoryState(addr, num_pages * PageSize, KMemoryState::All, KMemoryState::Free,
                                   KMemoryPermission::None, KMemoryPermission::None,
-                                  KMemoryAttribute::None, KMemoryAttribute::None)
-               .IsSuccess());
+                                  KMemoryAttribute::None, KMemoryAttribute::None) == ResultSuccess);
 
     // Create an update allocator.
-    Result allocator_result{ResultSuccess};
+    Result allocator_result;
     KMemoryBlockManagerUpdateAllocator allocator(std::addressof(allocator_result),
                                                  m_memory_block_slab_manager);
+    R_TRY(allocator_result);
+
+    // We're going to perform an update, so create a helper.
+    KScopedPageTableUpdater updater(this);
 
     // Perform mapping operation.
     if (is_pa_valid) {
-        R_TRY(this->Operate(addr, num_pages, perm, OperationType::Map, phys_addr));
+        const KPageProperties properties = {perm, false, false, DisableMergeAttribute::DisableHead};
+        R_TRY(this->Operate(addr, num_pages, properties.perm, OperationType::Map, phys_addr));
     } else {
-        UNIMPLEMENTED();
+        R_TRY(this->AllocateAndMapPagesImpl(updater.GetPageList(), addr, num_pages, perm));
     }
 
     // Update the blocks.
@@ -2116,28 +2247,45 @@ Result KPageTable::MapPages(VAddr* out_addr, size_t num_pages, size_t alignment,
     R_SUCCEED();
 }
 
-Result KPageTable::UnmapPages(VAddr addr, const KPageGroup& page_linked_list) {
-    ASSERT(this->IsLockedByCurrentThread());
+Result KPageTable::MapPages(KProcessAddress address, size_t num_pages, KMemoryState state,
+                            KMemoryPermission perm) {
+    // Check that the map is in range.
+    const size_t size = num_pages * PageSize;
+    R_UNLESS(this->CanContain(address, size, state), ResultInvalidCurrentMemory);
 
-    VAddr cur_addr{addr};
+    // Lock the table.
+    KScopedLightLock lk(m_general_lock);
 
-    for (const auto& node : page_linked_list) {
-        if (const auto result{Operate(cur_addr, node.GetNumPages(), KMemoryPermission::None,
-                                      OperationType::Unmap)};
-            result.IsError()) {
-            R_RETURN(result);
-        }
+    // Check the memory state.
+    size_t num_allocator_blocks;
+    R_TRY(this->CheckMemoryState(std::addressof(num_allocator_blocks), address, size,
+                                 KMemoryState::All, KMemoryState::Free, KMemoryPermission::None,
+                                 KMemoryPermission::None, KMemoryAttribute::None,
+                                 KMemoryAttribute::None));
 
-        cur_addr += node.GetNumPages() * PageSize;
-    }
+    // Create an update allocator.
+    Result allocator_result;
+    KMemoryBlockManagerUpdateAllocator allocator(std::addressof(allocator_result),
+                                                 m_memory_block_slab_manager, num_allocator_blocks);
+    R_TRY(allocator_result);
+
+    // We're going to perform an update, so create a helper.
+    KScopedPageTableUpdater updater(this);
+
+    // Map the pages.
+    R_TRY(this->AllocateAndMapPagesImpl(updater.GetPageList(), address, num_pages, perm));
+
+    // Update the blocks.
+    m_memory_block_manager.Update(std::addressof(allocator), address, num_pages, state, perm,
+                                  KMemoryAttribute::None, KMemoryBlockDisableMergeAttribute::Normal,
+                                  KMemoryBlockDisableMergeAttribute::None);
 
     R_SUCCEED();
 }
 
-Result KPageTable::UnmapPages(VAddr address, KPageGroup& page_linked_list, KMemoryState state) {
+Result KPageTable::UnmapPages(KProcessAddress address, size_t num_pages, KMemoryState state) {
     // Check that the unmap is in range.
-    const size_t num_pages{page_linked_list.GetNumPages()};
-    const size_t size{num_pages * PageSize};
+    const size_t size = num_pages * PageSize;
     R_UNLESS(this->Contains(address, size), ResultInvalidCurrentMemory);
 
     // Lock the table.
@@ -2151,13 +2299,18 @@ Result KPageTable::UnmapPages(VAddr address, KPageGroup& page_linked_list, KMemo
                                  KMemoryAttribute::None));
 
     // Create an update allocator.
-    Result allocator_result{ResultSuccess};
+    Result allocator_result;
     KMemoryBlockManagerUpdateAllocator allocator(std::addressof(allocator_result),
                                                  m_memory_block_slab_manager, num_allocator_blocks);
     R_TRY(allocator_result);
 
+    // We're going to perform an update, so create a helper.
+    KScopedPageTableUpdater updater(this);
+
     // Perform the unmap.
-    R_TRY(UnmapPages(address, page_linked_list));
+    const KPageProperties unmap_properties = {KMemoryPermission::None, false, false,
+                                              DisableMergeAttribute::None};
+    R_TRY(this->Operate(address, num_pages, unmap_properties.perm, OperationType::Unmap));
 
     // Update the blocks.
     m_memory_block_manager.Update(std::addressof(allocator), address, num_pages, KMemoryState::Free,
@@ -2168,29 +2321,130 @@ Result KPageTable::UnmapPages(VAddr address, KPageGroup& page_linked_list, KMemo
     R_SUCCEED();
 }
 
-Result KPageTable::UnmapPages(VAddr address, size_t num_pages, KMemoryState state) {
-    // Check that the unmap is in range.
+Result KPageTable::MapPageGroup(KProcessAddress* out_addr, const KPageGroup& pg,
+                                KProcessAddress region_start, size_t region_num_pages,
+                                KMemoryState state, KMemoryPermission perm) {
+    ASSERT(!this->IsLockedByCurrentThread());
+
+    // Ensure this is a valid map request.
+    const size_t num_pages = pg.GetNumPages();
+    R_UNLESS(this->CanContain(region_start, region_num_pages * PageSize, state),
+             ResultInvalidCurrentMemory);
+    R_UNLESS(num_pages < region_num_pages, ResultOutOfMemory);
+
+    // Lock the table.
+    KScopedLightLock lk(m_general_lock);
+
+    // Find a random address to map at.
+    KProcessAddress addr = this->FindFreeArea(region_start, region_num_pages, num_pages, PageSize,
+                                              0, this->GetNumGuardPages());
+    R_UNLESS(addr != 0, ResultOutOfMemory);
+    ASSERT(this->CanContain(addr, num_pages * PageSize, state));
+    ASSERT(this->CheckMemoryState(addr, num_pages * PageSize, KMemoryState::All, KMemoryState::Free,
+                                  KMemoryPermission::None, KMemoryPermission::None,
+                                  KMemoryAttribute::None, KMemoryAttribute::None) == ResultSuccess);
+
+    // Create an update allocator.
+    Result allocator_result;
+    KMemoryBlockManagerUpdateAllocator allocator(std::addressof(allocator_result),
+                                                 m_memory_block_slab_manager);
+    R_TRY(allocator_result);
+
+    // We're going to perform an update, so create a helper.
+    KScopedPageTableUpdater updater(this);
+
+    // Perform mapping operation.
+    const KPageProperties properties = {perm, state == KMemoryState::Io, false,
+                                        DisableMergeAttribute::DisableHead};
+    R_TRY(this->MapPageGroupImpl(updater.GetPageList(), addr, pg, properties, false));
+
+    // Update the blocks.
+    m_memory_block_manager.Update(std::addressof(allocator), addr, num_pages, state, perm,
+                                  KMemoryAttribute::None, KMemoryBlockDisableMergeAttribute::Normal,
+                                  KMemoryBlockDisableMergeAttribute::None);
+
+    // We successfully mapped the pages.
+    *out_addr = addr;
+    R_SUCCEED();
+}
+
+Result KPageTable::MapPageGroup(KProcessAddress addr, const KPageGroup& pg, KMemoryState state,
+                                KMemoryPermission perm) {
+    ASSERT(!this->IsLockedByCurrentThread());
+
+    // Ensure this is a valid map request.
+    const size_t num_pages = pg.GetNumPages();
     const size_t size = num_pages * PageSize;
-    R_UNLESS(this->Contains(address, size), ResultInvalidCurrentMemory);
+    R_UNLESS(this->CanContain(addr, size, state), ResultInvalidCurrentMemory);
 
     // Lock the table.
     KScopedLightLock lk(m_general_lock);
 
-    // Check the memory state.
-    size_t num_allocator_blocks{};
+    // Check if state allows us to map.
+    size_t num_allocator_blocks;
+    R_TRY(this->CheckMemoryState(std::addressof(num_allocator_blocks), addr, size,
+                                 KMemoryState::All, KMemoryState::Free, KMemoryPermission::None,
+                                 KMemoryPermission::None, KMemoryAttribute::None,
+                                 KMemoryAttribute::None));
+
+    // Create an update allocator.
+    Result allocator_result;
+    KMemoryBlockManagerUpdateAllocator allocator(std::addressof(allocator_result),
+                                                 m_memory_block_slab_manager, num_allocator_blocks);
+    R_TRY(allocator_result);
+
+    // We're going to perform an update, so create a helper.
+    KScopedPageTableUpdater updater(this);
+
+    // Perform mapping operation.
+    const KPageProperties properties = {perm, state == KMemoryState::Io, false,
+                                        DisableMergeAttribute::DisableHead};
+    R_TRY(this->MapPageGroupImpl(updater.GetPageList(), addr, pg, properties, false));
+
+    // Update the blocks.
+    m_memory_block_manager.Update(std::addressof(allocator), addr, num_pages, state, perm,
+                                  KMemoryAttribute::None, KMemoryBlockDisableMergeAttribute::Normal,
+                                  KMemoryBlockDisableMergeAttribute::None);
+
+    // We successfully mapped the pages.
+    R_SUCCEED();
+}
+
+Result KPageTable::UnmapPageGroup(KProcessAddress address, const KPageGroup& pg,
+                                  KMemoryState state) {
+    ASSERT(!this->IsLockedByCurrentThread());
+
+    // Ensure this is a valid unmap request.
+    const size_t num_pages = pg.GetNumPages();
+    const size_t size = num_pages * PageSize;
+    R_UNLESS(this->CanContain(address, size, state), ResultInvalidCurrentMemory);
+
+    // Lock the table.
+    KScopedLightLock lk(m_general_lock);
+
+    // Check if state allows us to unmap.
+    size_t num_allocator_blocks;
     R_TRY(this->CheckMemoryState(std::addressof(num_allocator_blocks), address, size,
                                  KMemoryState::All, state, KMemoryPermission::None,
                                  KMemoryPermission::None, KMemoryAttribute::All,
                                  KMemoryAttribute::None));
 
+    // Check that the page group is valid.
+    R_UNLESS(this->IsValidPageGroup(pg, address, num_pages), ResultInvalidCurrentMemory);
+
     // Create an update allocator.
-    Result allocator_result{ResultSuccess};
+    Result allocator_result;
     KMemoryBlockManagerUpdateAllocator allocator(std::addressof(allocator_result),
                                                  m_memory_block_slab_manager, num_allocator_blocks);
     R_TRY(allocator_result);
 
-    // Perform the unmap.
-    R_TRY(Operate(address, num_pages, KMemoryPermission::None, OperationType::Unmap));
+    // We're going to perform an update, so create a helper.
+    KScopedPageTableUpdater updater(this);
+
+    // Perform unmapping operation.
+    const KPageProperties properties = {KMemoryPermission::None, false, false,
+                                        DisableMergeAttribute::None};
+    R_TRY(this->Operate(address, num_pages, properties.perm, OperationType::Unmap));
 
     // Update the blocks.
     m_memory_block_manager.Update(std::addressof(allocator), address, num_pages, KMemoryState::Free,
@@ -2550,54 +2804,6 @@ Result KPageTable::SetHeapSize(VAddr* out, size_t size) {
     }
 }
 
-ResultVal<VAddr> KPageTable::AllocateAndMapMemory(size_t needed_num_pages, size_t align,
-                                                  bool is_map_only, VAddr region_start,
-                                                  size_t region_num_pages, KMemoryState state,
-                                                  KMemoryPermission perm, PAddr map_addr) {
-    KScopedLightLock lk(m_general_lock);
-
-    R_UNLESS(CanContain(region_start, region_num_pages * PageSize, state),
-             ResultInvalidCurrentMemory);
-    R_UNLESS(region_num_pages > needed_num_pages, ResultOutOfMemory);
-    const VAddr addr{
-        AllocateVirtualMemory(region_start, region_num_pages, needed_num_pages, align)};
-    R_UNLESS(addr, ResultOutOfMemory);
-
-    // Create an update allocator.
-    Result allocator_result{ResultSuccess};
-    KMemoryBlockManagerUpdateAllocator allocator(std::addressof(allocator_result),
-                                                 m_memory_block_slab_manager);
-
-    if (is_map_only) {
-        R_TRY(Operate(addr, needed_num_pages, perm, OperationType::Map, map_addr));
-    } else {
-        // Create a page group tohold the pages we allocate.
-        KPageGroup pg{m_kernel, m_block_info_manager};
-
-        R_TRY(m_system.Kernel().MemoryManager().AllocateAndOpen(
-            &pg, needed_num_pages,
-            KMemoryManager::EncodeOption(m_memory_pool, m_allocation_option)));
-
-        // Ensure that the page group is closed when we're done working with it.
-        SCOPE_EXIT({ pg.Close(); });
-
-        // Clear all pages.
-        for (const auto& it : pg) {
-            std::memset(m_system.DeviceMemory().GetPointer<void>(it.GetAddress()),
-                        m_heap_fill_value, it.GetSize());
-        }
-
-        R_TRY(Operate(addr, needed_num_pages, pg, OperationType::MapGroup));
-    }
-
-    // Update the blocks.
-    m_memory_block_manager.Update(std::addressof(allocator), addr, needed_num_pages, state, perm,
-                                  KMemoryAttribute::None, KMemoryBlockDisableMergeAttribute::Normal,
-                                  KMemoryBlockDisableMergeAttribute::None);
-
-    return addr;
-}
-
 Result KPageTable::LockForMapDeviceAddressSpace(bool* out_is_io, VAddr address, size_t size,
                                                 KMemoryPermission perm, bool is_aligned,
                                                 bool check_heap) {
diff --git a/src/core/hle/kernel/k_page_table.h b/src/core/hle/kernel/k_page_table.h
index 0a454b05b..367dab613 100644
--- a/src/core/hle/kernel/k_page_table.h
+++ b/src/core/hle/kernel/k_page_table.h
@@ -24,12 +24,36 @@ class System;
 
 namespace Kernel {
 
+enum class DisableMergeAttribute : u8 {
+    None = (0U << 0),
+    DisableHead = (1U << 0),
+    DisableHeadAndBody = (1U << 1),
+    EnableHeadAndBody = (1U << 2),
+    DisableTail = (1U << 3),
+    EnableTail = (1U << 4),
+    EnableAndMergeHeadBodyTail = (1U << 5),
+    EnableHeadBodyTail = EnableHeadAndBody | EnableTail,
+    DisableHeadBodyTail = DisableHeadAndBody | DisableTail,
+};
+
+struct KPageProperties {
+    KMemoryPermission perm;
+    bool io;
+    bool uncached;
+    DisableMergeAttribute disable_merge_attributes;
+};
+static_assert(std::is_trivial_v<KPageProperties>);
+static_assert(sizeof(KPageProperties) == sizeof(u32));
+
 class KBlockInfoManager;
 class KMemoryBlockManager;
 class KResourceLimit;
 class KSystemResource;
 
 class KPageTable final {
+protected:
+    struct PageLinkedList;
+
 public:
     enum class ICacheInvalidationStrategy : u32 { InvalidateRange, InvalidateAll };
 
@@ -57,27 +81,12 @@ public:
     Result UnmapPhysicalMemory(VAddr addr, size_t size);
     Result MapMemory(VAddr dst_addr, VAddr src_addr, size_t size);
     Result UnmapMemory(VAddr dst_addr, VAddr src_addr, size_t size);
-    Result MapPages(VAddr addr, KPageGroup& page_linked_list, KMemoryState state,
-                    KMemoryPermission perm);
-    Result MapPages(VAddr* out_addr, size_t num_pages, size_t alignment, PAddr phys_addr,
-                    KMemoryState state, KMemoryPermission perm) {
-        R_RETURN(this->MapPages(out_addr, num_pages, alignment, phys_addr, true,
-                                this->GetRegionAddress(state),
-                                this->GetRegionSize(state) / PageSize, state, perm));
-    }
-    Result UnmapPages(VAddr addr, KPageGroup& page_linked_list, KMemoryState state);
-    Result UnmapPages(VAddr address, size_t num_pages, KMemoryState state);
     Result SetProcessMemoryPermission(VAddr addr, size_t size, Svc::MemoryPermission svc_perm);
     KMemoryInfo QueryInfo(VAddr addr);
     Result SetMemoryPermission(VAddr addr, size_t size, Svc::MemoryPermission perm);
     Result SetMemoryAttribute(VAddr addr, size_t size, u32 mask, u32 attr);
     Result SetMaxHeapSize(size_t size);
     Result SetHeapSize(VAddr* out, size_t size);
-    ResultVal<VAddr> AllocateAndMapMemory(size_t needed_num_pages, size_t align, bool is_map_only,
-                                          VAddr region_start, size_t region_num_pages,
-                                          KMemoryState state, KMemoryPermission perm,
-                                          PAddr map_addr = 0);
-
     Result LockForMapDeviceAddressSpace(bool* out_is_io, VAddr address, size_t size,
                                         KMemoryPermission perm, bool is_aligned, bool check_heap);
     Result LockForUnmapDeviceAddressSpace(VAddr address, size_t size, bool check_heap);
@@ -113,6 +122,40 @@ public:
 
     bool CanContain(VAddr addr, size_t size, KMemoryState state) const;
 
+    Result MapPages(KProcessAddress* out_addr, size_t num_pages, size_t alignment,
+                    KPhysicalAddress phys_addr, KProcessAddress region_start,
+                    size_t region_num_pages, KMemoryState state, KMemoryPermission perm) {
+        R_RETURN(this->MapPages(out_addr, num_pages, alignment, phys_addr, true, region_start,
+                                region_num_pages, state, perm));
+    }
+
+    Result MapPages(KProcessAddress* out_addr, size_t num_pages, size_t alignment,
+                    KPhysicalAddress phys_addr, KMemoryState state, KMemoryPermission perm) {
+        R_RETURN(this->MapPages(out_addr, num_pages, alignment, phys_addr, true,
+                                this->GetRegionAddress(state),
+                                this->GetRegionSize(state) / PageSize, state, perm));
+    }
+
+    Result MapPages(KProcessAddress* out_addr, size_t num_pages, KMemoryState state,
+                    KMemoryPermission perm) {
+        R_RETURN(this->MapPages(out_addr, num_pages, PageSize, 0, false,
+                                this->GetRegionAddress(state),
+                                this->GetRegionSize(state) / PageSize, state, perm));
+    }
+
+    Result MapPages(KProcessAddress address, size_t num_pages, KMemoryState state,
+                    KMemoryPermission perm);
+    Result UnmapPages(KProcessAddress address, size_t num_pages, KMemoryState state);
+
+    Result MapPageGroup(KProcessAddress* out_addr, const KPageGroup& pg,
+                        KProcessAddress region_start, size_t region_num_pages, KMemoryState state,
+                        KMemoryPermission perm);
+    Result MapPageGroup(KProcessAddress address, const KPageGroup& pg, KMemoryState state,
+                        KMemoryPermission perm);
+    Result UnmapPageGroup(KProcessAddress address, const KPageGroup& pg, KMemoryState state);
+    void RemapPageGroup(PageLinkedList* page_list, KProcessAddress address, size_t size,
+                        const KPageGroup& pg);
+
 protected:
     struct PageLinkedList {
     private:
@@ -166,11 +209,9 @@ private:
     static constexpr KMemoryAttribute DefaultMemoryIgnoreAttr =
         KMemoryAttribute::IpcLocked | KMemoryAttribute::DeviceShared;
 
-    Result MapPages(VAddr addr, const KPageGroup& page_linked_list, KMemoryPermission perm);
-    Result MapPages(VAddr* out_addr, size_t num_pages, size_t alignment, PAddr phys_addr,
-                    bool is_pa_valid, VAddr region_start, size_t region_num_pages,
-                    KMemoryState state, KMemoryPermission perm);
-    Result UnmapPages(VAddr addr, const KPageGroup& page_linked_list);
+    Result MapPages(KProcessAddress* out_addr, size_t num_pages, size_t alignment,
+                    KPhysicalAddress phys_addr, bool is_pa_valid, KProcessAddress region_start,
+                    size_t region_num_pages, KMemoryState state, KMemoryPermission perm);
     bool IsRegionContiguous(VAddr addr, u64 size) const;
     void AddRegionToPages(VAddr start, size_t num_pages, KPageGroup& page_linked_list);
     KMemoryInfo QueryInfoImpl(VAddr addr);
@@ -265,6 +306,11 @@ private:
     void CleanupForIpcClientOnServerSetupFailure(PageLinkedList* page_list, VAddr address,
                                                  size_t size, KMemoryPermission prot_perm);
 
+    Result AllocateAndMapPagesImpl(PageLinkedList* page_list, KProcessAddress address,
+                                   size_t num_pages, KMemoryPermission perm);
+    Result MapPageGroupImpl(PageLinkedList* page_list, KProcessAddress address,
+                            const KPageGroup& pg, const KPageProperties properties, bool reuse_ll);
+
     mutable KLightLock m_general_lock;
     mutable KLightLock m_map_physical_memory_lock;
 
diff --git a/src/core/hle/kernel/k_process.cpp b/src/core/hle/kernel/k_process.cpp
index a1abf5d68..e201bb0cd 100644
--- a/src/core/hle/kernel/k_process.cpp
+++ b/src/core/hle/kernel/k_process.cpp
@@ -417,9 +417,8 @@ Result KProcess::LoadFromMetadata(const FileSys::ProgramMetadata& metadata, std:
 }
 
 void KProcess::Run(s32 main_thread_priority, u64 stack_size) {
-    AllocateMainThreadStack(stack_size);
+    ASSERT(AllocateMainThreadStack(stack_size) == ResultSuccess);
     resource_limit->Reserve(LimitableResource::ThreadCountMax, 1);
-    resource_limit->Reserve(LimitableResource::PhysicalMemoryMax, main_thread_stack_size);
 
     const std::size_t heap_capacity{memory_usage_capacity - (main_thread_stack_size + image_size)};
     ASSERT(!page_table.SetMaxHeapSize(heap_capacity).IsError());
@@ -675,20 +674,31 @@ void KProcess::ChangeState(State new_state) {
 }
 
 Result KProcess::AllocateMainThreadStack(std::size_t stack_size) {
-    ASSERT(stack_size);
-
-    // The kernel always ensures that the given stack size is page aligned.
-    main_thread_stack_size = Common::AlignUp(stack_size, PageSize);
-
-    const VAddr start{page_table.GetStackRegionStart()};
-    const std::size_t size{page_table.GetStackRegionEnd() - start};
-
-    CASCADE_RESULT(main_thread_stack_top,
-                   page_table.AllocateAndMapMemory(
-                       main_thread_stack_size / PageSize, PageSize, false, start, size / PageSize,
-                       KMemoryState::Stack, KMemoryPermission::UserReadWrite));
+    // Ensure that we haven't already allocated stack.
+    ASSERT(main_thread_stack_size == 0);
+
+    // Ensure that we're allocating a valid stack.
+    stack_size = Common::AlignUp(stack_size, PageSize);
+    // R_UNLESS(stack_size + image_size <= m_max_process_memory, ResultOutOfMemory);
+    R_UNLESS(stack_size + image_size >= image_size, ResultOutOfMemory);
+
+    // Place a tentative reservation of memory for our new stack.
+    KScopedResourceReservation mem_reservation(this, Svc::LimitableResource::PhysicalMemoryMax,
+                                               stack_size);
+    R_UNLESS(mem_reservation.Succeeded(), ResultLimitReached);
+
+    // Allocate and map our stack.
+    if (stack_size) {
+        KProcessAddress stack_bottom;
+        R_TRY(page_table.MapPages(std::addressof(stack_bottom), stack_size / PageSize,
+                                  KMemoryState::Stack, KMemoryPermission::UserReadWrite));
+
+        main_thread_stack_top = stack_bottom + stack_size;
+        main_thread_stack_size = stack_size;
+    }
 
-    main_thread_stack_top += main_thread_stack_size;
+    // We succeeded! Commit our memory reservation.
+    mem_reservation.Commit();
 
     R_SUCCEED();
 }
diff --git a/src/core/hle/kernel/k_shared_memory.cpp b/src/core/hle/kernel/k_shared_memory.cpp
index 3cf2b5d91..df505edfe 100644
--- a/src/core/hle/kernel/k_shared_memory.cpp
+++ b/src/core/hle/kernel/k_shared_memory.cpp
@@ -94,15 +94,15 @@ Result KSharedMemory::Map(KProcess& target_process, VAddr address, std::size_t m
         R_UNLESS(map_perm == test_perm, ResultInvalidNewMemoryPermission);
     }
 
-    return target_process.PageTable().MapPages(address, *page_group, KMemoryState::Shared,
-                                               ConvertToKMemoryPermission(map_perm));
+    return target_process.PageTable().MapPageGroup(address, *page_group, KMemoryState::Shared,
+                                                   ConvertToKMemoryPermission(map_perm));
 }
 
 Result KSharedMemory::Unmap(KProcess& target_process, VAddr address, std::size_t unmap_size) {
     // Validate the size.
     R_UNLESS(size == unmap_size, ResultInvalidSize);
 
-    return target_process.PageTable().UnmapPages(address, *page_group, KMemoryState::Shared);
+    return target_process.PageTable().UnmapPageGroup(address, *page_group, KMemoryState::Shared);
 }
 
 } // namespace Kernel
diff --git a/src/core/hle/kernel/svc.cpp b/src/core/hle/kernel/svc.cpp
index aca442196..67fa5d71c 100644
--- a/src/core/hle/kernel/svc.cpp
+++ b/src/core/hle/kernel/svc.cpp
@@ -1492,8 +1492,8 @@ static Result MapProcessMemory(Core::System& system, VAddr dst_address, Handle p
         KMemoryAttribute::All, KMemoryAttribute::None));
 
     // Map the group.
-    R_TRY(dst_pt.MapPages(dst_address, pg, KMemoryState::SharedCode,
-                          KMemoryPermission::UserReadWrite));
+    R_TRY(dst_pt.MapPageGroup(dst_address, pg, KMemoryState::SharedCode,
+                              KMemoryPermission::UserReadWrite));
 
     return ResultSuccess;
 }