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[nca] Use better tight loop allocation schemes (none at all) for AES decrypt/encrypt and force MbedTLS to use AES x86_64 instructions (#2750)

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Uses stack instead of allocating stuff haphazardly (16 bytes and 512 bytes respectively) - removes malloc() pollution and all that nasty stuff from tight loops
Original work by Ribbit but edited by me.
Will NOT bring a massive speedup since the main bottleneck is mbedtls itself, but may bring nice oddities to STARTUP TIMES nonetheless.
AES instructions being forced wont affect CPUs without them since there is always a runtime check for them.

Signed-off-by: lizzie lizzie@eden-emu.dev
Co-authored-by: Ribbit <ribbit@placeholder.com>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/2750
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Co-authored-by: lizzie <lizzie@eden-emu.dev>
Co-committed-by: lizzie <lizzie@eden-emu.dev>
This commit is contained in:
lizzie
2025-10-17 05:08:51 +02:00
committed by crueter
parent 551f244dfd
commit 440ee4916d
9 changed files with 200 additions and 130 deletions
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src/core/crypto/xts_encryption_layer.cpp
+59 -32
View File
@@ -5,12 +5,13 @@
// SPDX-License-Identifier: GPL-2.0-or-later
#include <algorithm>
#include <array>
#include <cstring>
#include "core/crypto/xts_encryption_layer.h"
namespace Core::Crypto {
constexpr u64 XTS_SECTOR_SIZE = 0x4000;
constexpr std::size_t XTS_SECTOR_SIZE = 0x4000;
XTSEncryptionLayer::XTSEncryptionLayer(FileSys::VirtualFile base_, Key256 key_)
: EncryptionLayer(std::move(base_)), cipher(key_, Mode::XTS) {}
@@ -19,41 +20,67 @@ std::size_t XTSEncryptionLayer::Read(u8* data, std::size_t length, std::size_t o
if (length == 0)
return 0;
const auto sector_offset = offset & 0x3FFF;
if (sector_offset == 0) {
if (length % XTS_SECTOR_SIZE == 0) {
std::vector<u8> raw = base->ReadBytes(length, offset);
cipher.XTSTranscode(raw.data(), raw.size(), data, offset / XTS_SECTOR_SIZE,
std::size_t total_read = 0;
// Handle initial unaligned part within a sector.
if (auto const sector_offset = offset % XTS_SECTOR_SIZE; sector_offset != 0) {
const std::size_t aligned_off = offset - sector_offset;
std::array<u8, XTS_SECTOR_SIZE> block{};
if (auto const got = base->Read(block.data(), XTS_SECTOR_SIZE, aligned_off); got > 0) {
if (got < XTS_SECTOR_SIZE)
std::memset(block.data() + got, 0, XTS_SECTOR_SIZE - got);
cipher.XTSTranscode(block.data(), XTS_SECTOR_SIZE, block.data(), aligned_off / XTS_SECTOR_SIZE,
XTS_SECTOR_SIZE, Op::Decrypt);
return raw.size();
auto const to_copy = std::min<std::size_t>(length, got > sector_offset ? got - sector_offset : 0);
if (to_copy > 0) {
std::memcpy(data, block.data() + sector_offset, to_copy);
data += to_copy;
offset += to_copy;
length -= to_copy;
total_read += to_copy;
}
} else {
return 0;
}
if (length > XTS_SECTOR_SIZE) {
const auto rem = length % XTS_SECTOR_SIZE;
const auto read = length - rem;
return Read(data, read, offset) + Read(data + read, rem, offset + read);
}
std::vector<u8> buffer = base->ReadBytes(XTS_SECTOR_SIZE, offset);
if (buffer.size() < XTS_SECTOR_SIZE)
buffer.resize(XTS_SECTOR_SIZE);
cipher.XTSTranscode(buffer.data(), buffer.size(), buffer.data(), offset / XTS_SECTOR_SIZE,
XTS_SECTOR_SIZE, Op::Decrypt);
std::memcpy(data, buffer.data(), (std::min)(buffer.size(), length));
return (std::min)(buffer.size(), length);
}
// offset does not fall on block boundary (0x4000)
std::vector<u8> block = base->ReadBytes(0x4000, offset - sector_offset);
if (block.size() < XTS_SECTOR_SIZE)
block.resize(XTS_SECTOR_SIZE);
cipher.XTSTranscode(block.data(), block.size(), block.data(),
(offset - sector_offset) / XTS_SECTOR_SIZE, XTS_SECTOR_SIZE, Op::Decrypt);
const std::size_t read = XTS_SECTOR_SIZE - sector_offset;
if (length + sector_offset < XTS_SECTOR_SIZE) {
std::memcpy(data, block.data() + sector_offset, std::min<u64>(length, read));
return std::min<u64>(length, read);
if (length > 0) {
// Process aligned middle inplace, in sector sized multiples.
while (length >= XTS_SECTOR_SIZE) {
const std::size_t req = (length / XTS_SECTOR_SIZE) * XTS_SECTOR_SIZE;
const std::size_t got = base->Read(data, req, offset);
if (got == 0) {
return total_read;
}
const std::size_t got_rounded = got - (got % XTS_SECTOR_SIZE);
if (got_rounded > 0) {
cipher.XTSTranscode(data, got_rounded, data, offset / XTS_SECTOR_SIZE, XTS_SECTOR_SIZE, Op::Decrypt);
data += got_rounded;
offset += got_rounded;
length -= got_rounded;
total_read += got_rounded;
}
// If we didn't get a full sector next, break to handle tail.
if (got_rounded != got) {
break;
}
}
// Handle tail within a sector, if any.
if (length > 0) {
std::array<u8, XTS_SECTOR_SIZE> block{};
const std::size_t got = base->Read(block.data(), XTS_SECTOR_SIZE, offset);
if (got > 0) {
if (got < XTS_SECTOR_SIZE) {
std::memset(block.data() + got, 0, XTS_SECTOR_SIZE - got);
}
cipher.XTSTranscode(block.data(), XTS_SECTOR_SIZE, block.data(),
offset / XTS_SECTOR_SIZE, XTS_SECTOR_SIZE, Op::Decrypt);
const std::size_t to_copy = std::min<std::size_t>(length, got);
std::memcpy(data, block.data(), to_copy);
total_read += to_copy;
}
}
}
std::memcpy(data, block.data() + sector_offset, read);
return read + Read(data + read, length - read, offset + read);
return total_read;
}
} // namespace Core::Crypto