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-rw-r--r--src/common/host_memory.cpp320
1 files changed, 320 insertions, 0 deletions
diff --git a/src/common/host_memory.cpp b/src/common/host_memory.cpp
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--- /dev/null
+++ b/src/common/host_memory.cpp
@@ -0,0 +1,320 @@
+#ifdef __linux__
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#elif defined(_WIN32) // ^^^ Linux ^^^ vvv Windows vvv
+#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")
+
+#endif // ^^^ Windows ^^^
+
+#include <mutex>
+
+#include "common/assert.h"
+#include "common/host_memory.h"
+#include "common/logging/log.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
+};
+
+#else
+
+#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