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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif
#include "gpu/command_buffer/service/dawn_service_memory_transfer_service.h"
#include "base/memory/raw_ptr.h"
#include "gpu/command_buffer/common/dawn_memory_transfer_handle.h"
#include "gpu/command_buffer/service/command_buffer_service.h"
#include "gpu/command_buffer/service/common_decoder.h"
namespace gpu {
namespace webgpu {
namespace {
class ReadHandleImpl
: public dawn::wire::server::MemoryTransferService::ReadHandle {
public:
ReadHandleImpl(scoped_refptr<Buffer> buffer, void* ptr, uint32_t size)
: buffer_(std::move(buffer)), ptr_(ptr), size_(size) {}
~ReadHandleImpl() override = default;
size_t SizeOfSerializeDataUpdate(size_t offset, size_t size) override {
// Nothing is serialized because we're using shared memory.
return 0;
}
void SerializeDataUpdate(const void* data,
size_t offset,
size_t size,
void* serializePointer) override {
// TODO(crbug.com/40061304): A compromised renderer could have a shared
// memory size not large enough to fit the GPU buffer contents. Instead of
// DCHECK, do a CHECK here to crash the release build. The crash is fine
// since it is not reachable from normal behavior. WebGPU post-V1 will have
// a refactored API.
CHECK_LE(offset, size_);
CHECK_LE(size, size_ - offset);
// Copy the data into the shared memory allocation.
// In the case of buffer mapping, this is the mapped GPU memory which we
// copy into client-visible shared memory.
memcpy(static_cast<uint8_t*>(ptr_) + offset, data, size);
}
private:
scoped_refptr<gpu::Buffer> buffer_;
// Pointer to client-visible shared memory owned by buffer_.
raw_ptr<void> ptr_;
uint32_t size_;
};
class WriteHandleImpl
: public dawn::wire::server::MemoryTransferService::WriteHandle {
public:
WriteHandleImpl(scoped_refptr<Buffer> buffer, const void* ptr, uint32_t size)
: buffer_(std::move(buffer)), ptr_(ptr), size_(size) {}
~WriteHandleImpl() override = default;
// The offset is always absolute offset from start of buffer
bool DeserializeDataUpdate(const void* deserialize_pointer,
size_t deserialize_size,
size_t offset,
size_t size) override {
// Nothing is serialized because we're using shared memory.
DCHECK_EQ(deserialize_size, 0u);
DCHECK(mTargetData);
DCHECK(ptr_);
if (offset > mDataLength || size > mDataLength - offset) {
return false;
}
if (offset > size_ || size > size_ - offset) {
return false;
}
// Copy from shared memory into the target buffer.
// mTargetData will always be the starting address
// of the backing buffer after the dawn side change.
memcpy(static_cast<uint8_t*>(mTargetData) + offset,
static_cast<const uint8_t*>(ptr_) + offset, size);
return true;
}
private:
scoped_refptr<gpu::Buffer> buffer_;
// Pointer to client-visible shared memory owned by buffer_.
raw_ptr<const void> ptr_;
uint32_t size_;
};
} // namespace
DawnServiceMemoryTransferService::DawnServiceMemoryTransferService(
CommonDecoder* decoder)
: dawn::wire::server::MemoryTransferService(), decoder_(decoder) {}
DawnServiceMemoryTransferService::~DawnServiceMemoryTransferService() = default;
bool DawnServiceMemoryTransferService::DeserializeReadHandle(
const void* deserialize_pointer,
size_t deserialize_size,
ReadHandle** read_handle) {
DCHECK(deserialize_pointer);
// Use CHECK instead of DCHECK because the cast of the memory to
// MemoryTransferHandle and subsequent reads won't be safe if deserialize_size
// is too small.
CHECK_EQ(deserialize_size, sizeof(MemoryTransferHandle));
const volatile MemoryTransferHandle* handle =
reinterpret_cast<const volatile MemoryTransferHandle*>(
deserialize_pointer);
uint32_t size = handle->size;
int32_t shm_id = handle->shm_id;
uint32_t shm_offset = handle->shm_offset;
scoped_refptr<gpu::Buffer> buffer =
decoder_->command_buffer_service()->GetTransferBuffer(shm_id);
if (buffer == nullptr) {
return false;
}
void* ptr = buffer->GetDataAddress(shm_offset, size);
if (ptr == nullptr) {
return false;
}
DCHECK(read_handle);
*read_handle = new ReadHandleImpl(std::move(buffer), ptr, size);
return true;
}
bool DawnServiceMemoryTransferService::DeserializeWriteHandle(
const void* deserialize_pointer,
size_t deserialize_size,
WriteHandle** write_handle) {
DCHECK(deserialize_pointer);
// Use CHECK instead of DCHECK because the cast of the memory to
// MemoryTransferHandle and subsequent reads won't be safe if deserialize_size
// is too small.
CHECK_EQ(deserialize_size, sizeof(MemoryTransferHandle));
const volatile MemoryTransferHandle* handle =
reinterpret_cast<const volatile MemoryTransferHandle*>(
deserialize_pointer);
uint32_t size = handle->size;
int32_t shm_id = handle->shm_id;
uint32_t shm_offset = handle->shm_offset;
scoped_refptr<gpu::Buffer> buffer =
decoder_->command_buffer_service()->GetTransferBuffer(shm_id);
if (buffer == nullptr) {
return false;
}
const void* ptr = buffer->GetDataAddress(shm_offset, size);
if (ptr == nullptr) {
return false;
}
DCHECK(write_handle);
*write_handle = new WriteHandleImpl(std::move(buffer), ptr, size);
return true;
}
} // namespace webgpu
} // namespace gpu
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