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Implement guard pages (#406)

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Hey, looking for feedback on my guard page implementation. 

I wasn't sure on how to structure the additional windows specific memory
flags, since the emulation backends won't like additional guard flag. I
opted to create a new `memory_permission_ext` enum to hold the guard
flag, and a `nt_memory_permission` struct to wrap the "common" memory
permission flags, with the new extended flags. This struct implicitly
coerces to the original `memory_permission` to reduce the amount of
changes for the PR.

This however meant that I changed signatures of `map_memory` and
`apply_memory_protection` in `memory_interface` to accommodate this new
structure, and was an afterthought.

The `map_nt_to_emulator_protection` function might also need some
attention now, too. For future reference, windows uses
[MiMakeProtectionMask](https://doxygen.reactos.org/d1/d9a/marea_8c.html#adfb66408771a4df77c1056cc2a99ef21)
in ntoskrnl to map `PAGE_*` flags to [MM PTE
constants](https://reactos.org/wiki/Techwiki:Memory_management_in_the_Windows_XP_kernel).

The test added to the `test-sample` binary seems to be passing.

Fixes #21
This commit is contained in:
Maurice Heumann
2025-07-17 17:41:06 +02:00
committed by GitHub
parent b34adbadbf 188b95af5d
commit 9e5a6b509b
13 changed files with 359 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
src/windows-emulator/memory_manager.cpp
View File

@@ -3,6 +3,7 @@
#include "memory_region.hpp"
#include "address_utils.hpp"
#include "memory_permission_ext.hpp"
#include <vector>
#include <optional>
@@ -73,7 +74,7 @@ namespace utils
static void deserialize(buffer_deserializer& buffer, memory_manager::committed_region& region)
{
region.length = static_cast<size_t>(buffer.read<uint64_t>());
region.permissions = buffer.read<memory_permission>();
region.permissions = buffer.read<nt_memory_permission>();
}
static void serialize(buffer_serializer& buffer, const memory_manager::reserved_region& region)
@@ -189,8 +190,8 @@ void memory_manager::deserialize_memory_state(utils::buffer_deserializer& buffer
}
}
bool memory_manager::protect_memory(const uint64_t address, const size_t size, const memory_permission permissions,
memory_permission* old_permissions)
bool memory_manager::protect_memory(const uint64_t address, const size_t size, const nt_memory_permission permissions,
nt_memory_permission* old_permissions)
{
const auto entry = this->find_reserved_region(address);
if (entry == this->reserved_regions_.end())
@@ -268,7 +269,7 @@ bool memory_manager::allocate_mmio(const uint64_t address, const size_t size, mm
return true;
}
bool memory_manager::allocate_memory(const uint64_t address, const size_t size, const memory_permission permissions,
bool memory_manager::allocate_memory(const uint64_t address, const size_t size, const nt_memory_permission permissions,
const bool reserve_only)
{
if (this->overlaps_reserved_region(address, size))
@@ -286,8 +287,9 @@ bool memory_manager::allocate_memory(const uint64_t address, const size_t size,
if (!reserve_only)
{
this->map_memory(address, size, permissions);
entry->second.committed_regions[address] = committed_region{size, memory_permission::read_write};
this->map_memory(address, size, permissions.is_guarded() ? memory_permission::none : permissions.common);
entry->second.committed_regions[address] =
committed_region{size, nt_memory_permission{memory_permission::read_write, permissions.extended}};
}
this->update_layout_version();
@@ -295,7 +297,7 @@ bool memory_manager::allocate_memory(const uint64_t address, const size_t size,
return true;
}
bool memory_manager::commit_memory(const uint64_t address, const size_t size, const memory_permission permissions)
bool memory_manager::commit_memory(const uint64_t address, const size_t size, const nt_memory_permission permissions)
{
const auto entry = this->find_reserved_region(address);
if (entry == this->reserved_regions_.end())
@@ -473,7 +475,7 @@ void memory_manager::unmap_all_memory()
this->reserved_regions_.clear();
}
uint64_t memory_manager::allocate_memory(const size_t size, const memory_permission permissions,
uint64_t memory_manager::allocate_memory(const size_t size, const nt_memory_permission permissions,
const bool reserve_only)
{
const auto allocation_base = this->find_free_allocation_base(size);
@@ -519,8 +521,8 @@ region_info memory_manager::get_region_info(const uint64_t address)
region_info result{};
result.start = MIN_ALLOCATION_ADDRESS;
result.length = static_cast<size_t>(MAX_ALLOCATION_ADDRESS - result.start);
result.permissions = memory_permission::none;
result.initial_permissions = memory_permission::none;
result.permissions = nt_memory_permission();
result.initial_permissions = nt_memory_permission();
result.allocation_base = {};
result.allocation_length = result.length;
result.is_committed = false;