#ifdef _WIN32
#ifdef _WIN32_WINNT
#undef _WIN32_WINNT
#endif
#define _WIN32_WINNT 0x0A00 // Windows 10
#include <windows.h>
#include <boost/icl/separate_interval_set.hpp>
#include <iterator>
#include <unordered_map>
#pragma comment(lib, "mincore.lib")
#elif defined(__linux__) // ^^^ Windows ^^^ vvv Linux vvv
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#endif // ^^^ Linux ^^^
#include <mutex>
#include "common/assert.h"
#include "common/host_memory.h"
#include "common/logging/log.h"
#include "common/scope_exit.h"
namespace Common {
constexpr size_t PageAlignment = 0x1000;
#ifdef _WIN32
class HostMemory::Impl {
public:
explicit Impl(size_t backing_size_, size_t virtual_size_)
: backing_size{backing_size_}, virtual_size{virtual_size_}, process{GetCurrentProcess()} {
// Allocate backing file map
backing_handle =
CreateFileMapping2(INVALID_HANDLE_VALUE, nullptr, FILE_MAP_WRITE | FILE_MAP_READ,
PAGE_READWRITE, SEC_COMMIT, backing_size, nullptr, nullptr, 0);
if (!backing_handle) {
throw std::bad_alloc{};
}
// Allocate a virtual memory for the backing file map as placeholder
backing_base = static_cast<u8*>(VirtualAlloc2(process, nullptr, backing_size,
MEM_RESERVE | MEM_RESERVE_PLACEHOLDER,
PAGE_NOACCESS, nullptr, 0));
if (!backing_base) {
Release();
throw std::bad_alloc{};
}
// Map backing placeholder
void* const ret = MapViewOfFile3(backing_handle, process, backing_base, 0, backing_size,
MEM_REPLACE_PLACEHOLDER, PAGE_READWRITE, nullptr, 0);
if (ret != backing_base) {
Release();
throw std::bad_alloc{};
}
// Allocate virtual address placeholder
virtual_base = static_cast<u8*>(VirtualAlloc2(process, nullptr, virtual_size,
MEM_RESERVE | MEM_RESERVE_PLACEHOLDER,
PAGE_NOACCESS, nullptr, 0));
if (!virtual_base) {
Release();
throw std::bad_alloc{};
}
}
~Impl() {
Release();
}
void Map(size_t virtual_offset, size_t host_offset, size_t length) {
std::unique_lock lock{placeholder_mutex};
if (!IsNiechePlaceholder(virtual_offset, length)) {
Split(virtual_offset, length);
}
ASSERT(placeholders.find({virtual_offset, virtual_offset + length}) == placeholders.end());
TrackPlaceholder(virtual_offset, host_offset, length);
MapView(virtual_offset, host_offset, length);
}
void Unmap(size_t virtual_offset, size_t length) {
std::lock_guard lock{placeholder_mutex};
// Unmap until there are no more placeholders
while (UnmapOnePlaceholder(virtual_offset, length)) {
}
}
void Protect(size_t virtual_offset, size_t length, bool read, bool write) {
DWORD new_flags{};
if (read && write) {
new_flags = PAGE_READWRITE;
} else if (read && !write) {
new_flags = PAGE_READONLY;
} else if (!read && !write) {
new_flags = PAGE_NOACCESS;
} else {
UNIMPLEMENTED_MSG("Protection flag combination read={} write={}", read, write);
}
DWORD old_flags{};
if (!VirtualProtect(virtual_base + virtual_offset, length, new_flags, &old_flags)) {
LOG_CRITICAL(HW_Memory, "Failed to change virtual memory protect rules");
}
}
const size_t backing_size; ///< Size of the backing memory in bytes
const size_t virtual_size; ///< Size of the virtual address placeholder in bytes
u8* backing_base{};
u8* virtual_base{};
private:
/// Release all resources in the object
void Release() {
if (!placeholders.empty()) {
for (const auto& placeholder : placeholders) {
if (!UnmapViewOfFile2(process, virtual_base + placeholder.lower(),
MEM_PRESERVE_PLACEHOLDER)) {
LOG_CRITICAL(HW_Memory, "Failed to unmap virtual memory placeholder");
}
}
Coalesce(0, virtual_size);
}
if (virtual_base) {
if (!VirtualFree(virtual_base, 0, MEM_RELEASE)) {
LOG_CRITICAL(HW_Memory, "Failed to free virtual memory");
}
}
if (backing_base) {
if (!UnmapViewOfFile2(process, backing_base, MEM_PRESERVE_PLACEHOLDER)) {
LOG_CRITICAL(HW_Memory, "Failed to unmap backing memory placeholder");
}
if (!VirtualFreeEx(process, backing_base, 0, MEM_RELEASE)) {
LOG_CRITICAL(HW_Memory, "Failed to free backing memory");
}
}
if (!CloseHandle(backing_handle)) {
LOG_CRITICAL(HW_Memory, "Failed to free backing memory file handle");
}
}
/// Unmap one placeholder in the given range (partial unmaps are supported)
/// Return true when there are no more placeholders to unmap
bool UnmapOnePlaceholder(size_t virtual_offset, size_t length) {
const auto it = placeholders.find({virtual_offset, virtual_offset + length});
const auto begin = placeholders.begin();
const auto end = placeholders.end();
if (it == end) {
return false;
}
const size_t placeholder_begin = it->lower();
const size_t placeholder_end = it->upper();
const size_t unmap_begin = std::max(virtual_offset, placeholder_begin);
const size_t unmap_end = std::min(virtual_offset + length, placeholder_end);
ASSERT(unmap_begin >= placeholder_begin && unmap_begin < placeholder_end);
ASSERT(unmap_end <= placeholder_end && unmap_end > placeholder_begin);
const auto host_pointer_it = placeholder_host_pointers.find(placeholder_begin);
ASSERT(host_pointer_it != placeholder_host_pointers.end());
const size_t host_offset = host_pointer_it->second;
const bool split_left = unmap_begin > placeholder_begin;
const bool split_right = unmap_end < placeholder_end;
if (!UnmapViewOfFile2(process, virtual_base + placeholder_begin,
MEM_PRESERVE_PLACEHOLDER)) {
LOG_CRITICAL(HW_Memory, "Failed to unmap placeholder");
}
// If we have to remap memory regions due to partial unmaps, we are in a data race as
// Windows doesn't support remapping memory without unmapping first. Avoid adding any extra
// logic within the panic region described below.
// Panic region, we are in a data race right now
if (split_left || split_right) {
Split(unmap_begin, unmap_end - unmap_begin);
}
if (split_left) {
MapView(placeholder_begin, host_offset, unmap_begin - placeholder_begin);
}
if (split_right) {
MapView(unmap_end, host_offset + unmap_end - placeholder_begin,
placeholder_end - unmap_end);
}
// End panic region
size_t coalesce_begin = unmap_begin;
if (!split_left) {
// Try to coalesce pages to the left
coalesce_begin = it == begin ? 0 : std::prev(it)->upper();
if (coalesce_begin != placeholder_begin) {
Coalesce(coalesce_begin, unmap_end - coalesce_begin);
}
}
if (!split_right) {
// Try to coalesce pages to the right
const auto next = std::next(it);
const size_t next_begin = next == end ? virtual_size : next->lower();
if (placeholder_end != next_begin) {
// We can coalesce to the right
Coalesce(coalesce_begin, next_begin - coalesce_begin);
}
}
// Remove and reinsert placeholder trackers
UntrackPlaceholder(it);
if (split_left) {
TrackPlaceholder(placeholder_begin, host_offset, unmap_begin - placeholder_begin);
}
if (split_right) {
TrackPlaceholder(unmap_end, host_offset + unmap_end - placeholder_begin,
placeholder_end - unmap_end);
}
return true;
}
void MapView(size_t virtual_offset, size_t host_offset, size_t length) {
if (!MapViewOfFile3(backing_handle, process, virtual_base + virtual_offset, host_offset,
length, MEM_REPLACE_PLACEHOLDER, PAGE_READWRITE, nullptr, 0)) {
LOG_CRITICAL(HW_Memory, "Failed to map placeholder");
}
}
void Split(size_t virtual_offset, size_t length) {
if (!VirtualFreeEx(process, reinterpret_cast<LPVOID>(virtual_base + virtual_offset), length,
MEM_RELEASE | MEM_PRESERVE_PLACEHOLDER)) {
LOG_CRITICAL(HW_Memory, "Failed to split placeholder");
}
}
void Coalesce(size_t virtual_offset, size_t length) {
if (!VirtualFreeEx(process, reinterpret_cast<LPVOID>(virtual_base + virtual_offset), length,
MEM_RELEASE | MEM_COALESCE_PLACEHOLDERS)) {
LOG_CRITICAL(HW_Memory, "Failed to coalesce placeholders");
}
}
void TrackPlaceholder(size_t virtual_offset, size_t host_offset, size_t length) {
placeholders.insert({virtual_offset, virtual_offset + length});
placeholder_host_pointers.emplace(virtual_offset, host_offset);
}
void UntrackPlaceholder(boost::icl::separate_interval_set<size_t>::iterator it) {
placeholders.erase(it);
placeholder_host_pointers.erase(it->lower());
}
/// Return true when a given memory region is a "nieche" and the placeholders don't have to be
/// splitted.
bool IsNiechePlaceholder(size_t virtual_offset, size_t length) const {
const auto it = placeholders.upper_bound({virtual_offset, virtual_offset + length});
if (it != placeholders.end() && it->lower() == virtual_offset + length) {
const bool is_root = it == placeholders.begin() && virtual_offset == 0;
return is_root || std::prev(it)->upper() == virtual_offset;
}
return false;
}
HANDLE process{}; ///< Current process handle
HANDLE backing_handle{}; ///< File based backing memory
std::mutex placeholder_mutex; ///< Mutex for placeholders
boost::icl::separate_interval_set<size_t> placeholders; ///< Mapped placeholders
std::unordered_map<size_t, size_t> placeholder_host_pointers; ///< Placeholder backing offset
};
#elif defined(__linux__) // ^^^ Windows ^^^ vvv Linux vvv
class HostMemory::Impl {
public:
explicit Impl(size_t backing_size_, size_t virtual_size_)
: backing_size{backing_size_}, virtual_size{virtual_size_} {
bool good = false;
SCOPE_EXIT({
if (!good) {
Release();
}
});
// Backing memory initialization
fd = memfd_create("HostMemory", 0);
if (fd == -1) {
LOG_CRITICAL(HW_Memory, "memfd_create failed: {}", strerror(errno));
throw std::bad_alloc{};
}
// Defined to extend the file with zeros
int ret = ftruncate(fd, backing_size);
if (ret != 0) {
LOG_CRITICAL(HW_Memory, "ftruncate failed with {}, are you out-of-memory?",
strerror(errno));
throw std::bad_alloc{};
}
backing_base = static_cast<u8*>(
mmap(nullptr, backing_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0));
if (backing_base == MAP_FAILED) {
LOG_CRITICAL(HW_Memory, "mmap failed: {}", strerror(errno));
throw std::bad_alloc{};
}
// Virtual memory initialization
virtual_base = static_cast<u8*>(
mmap(nullptr, virtual_size, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0));
if (virtual_base == MAP_FAILED) {
LOG_CRITICAL(HW_Memory, "mmap failed: {}", strerror(errno));
throw std::bad_alloc{};
}
good = true;
}
~Impl() {
Release();
}
void Map(size_t virtual_offset, size_t host_offset, size_t length) {
void* ret = mmap(virtual_base + virtual_offset, length, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_FIXED, fd, host_offset);
ASSERT_MSG(ret != MAP_FAILED, "mmap failed: {}", strerror(errno));
}
void Unmap(size_t virtual_offset, size_t length) {
// The method name is wrong. We're still talking about the virtual range.
// We don't want to unmap, we want to reserve this memory.
void* ret = mmap(virtual_base + virtual_offset, length, PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
ASSERT_MSG(ret != MAP_FAILED, "mmap failed: {}", strerror(errno));
}
void Protect(size_t virtual_offset, size_t length, bool read, bool write) {
int flags = 0;
if (read) {
flags |= PROT_READ;
}
if (write) {
flags |= PROT_WRITE;
}
int ret = mprotect(virtual_base + virtual_offset, length, flags);
ASSERT_MSG(ret == 0, "mprotect failed: {}", strerror(errno));
}
const size_t backing_size; ///< Size of the backing memory in bytes
const size_t virtual_size; ///< Size of the virtual address placeholder in bytes
u8* backing_base{reinterpret_cast<u8*>(MAP_FAILED)};
u8* virtual_base{reinterpret_cast<u8*>(MAP_FAILED)};
private:
/// Release all resources in the object
void Release() {
if (virtual_base != MAP_FAILED) {
int ret = munmap(virtual_base, virtual_size);
ASSERT_MSG(ret == 0, "munmap failed: {}", strerror(errno));
}
if (backing_base != MAP_FAILED) {
int ret = munmap(backing_base, backing_size);
ASSERT_MSG(ret == 0, "munmap failed: {}", strerror(errno));
}
if (fd != -1) {
int ret = close(fd);
ASSERT_MSG(ret == 0, "close failed: {}", strerror(errno));
}
}
int fd{-1}; // memfd file descriptor, -1 is the error value of memfd_create
};
#else // ^^^ Linux ^^^
#error Please implement the host memory for your platform
#endif
HostMemory::HostMemory(size_t backing_size, size_t virtual_size)
: impl{std::make_unique<HostMemory::Impl>(backing_size, virtual_size)},
backing_base{impl->backing_base}, virtual_base{impl->virtual_base} {}
HostMemory::~HostMemory() = default;
HostMemory::HostMemory(HostMemory&&) noexcept = default;
HostMemory& HostMemory::operator=(HostMemory&&) noexcept = default;
void HostMemory::Map(size_t virtual_offset, size_t host_offset, size_t length) {
ASSERT(virtual_offset % PageAlignment == 0);
ASSERT(host_offset % PageAlignment == 0);
ASSERT(length % PageAlignment == 0);
ASSERT(virtual_offset + length <= impl->virtual_size);
ASSERT(host_offset + length <= impl->backing_size);
if (length == 0) {
return;
}
impl->Map(virtual_offset, host_offset, length);
}
void HostMemory::Unmap(size_t virtual_offset, size_t length) {
ASSERT(virtual_offset % PageAlignment == 0);
ASSERT(length % PageAlignment == 0);
ASSERT(virtual_offset + length <= impl->virtual_size);
if (length == 0) {
return;
}
impl->Unmap(virtual_offset, length);
}
void HostMemory::Protect(size_t virtual_offset, size_t length, bool read, bool write) {
ASSERT(virtual_offset % PageAlignment == 0);
ASSERT(length % PageAlignment == 0);
ASSERT(virtual_offset + length <= impl->virtual_size);
if (length == 0) {
return;
}
impl->Protect(virtual_offset, length, read, write);
}
} // namespace Common
