src/graphics/drivers/misc/goldfish/pipe_connection.cc - fuchsia - Git at Google

 // Copyright 2019 The Fuchsia Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "src/graphics/drivers/misc/goldfish/pipe_connection.h"

 #include <fidl/fuchsia.hardware.goldfish/cpp/wire.h>
 #include <lib/driver/logging/cpp/logger.h>
 #include <lib/fzl/owned-vmo-mapper.h>
 #include <lib/trace/event.h>
 #include <lib/zx/bti.h>
 #include <zircon/status.h>

 #include <fbl/auto_lock.h>

 #include "src/devices/lib/goldfish/pipe_headers/include/base.h"
 #include "src/graphics/drivers/misc/goldfish/pipe_device.h"

 namespace goldfish {
 namespace {

 static const char* kTag = "GoldfishPipe";

 constexpr size_t DEFAULT_BUFFER_SIZE = 8192;

 constexpr zx_signals_t SIGNALS = fuchsia_hardware_goldfish::wire::kSignalReadable |
                                  fuchsia_hardware_goldfish::wire::kSignalWritable;

 }  // namespace

 PipeConnection::PipeConnection(PipeDevice* pipe, async_dispatcher_t* dispatcher, OnBindFn on_bind,
                                OnCloseFn on_close)
     : on_bind_(std::move(on_bind)),
       on_close_(std::move(on_close)),
       dispatcher_(dispatcher),
       pipe_(pipe) {}

 PipeConnection::~PipeConnection() {
   fbl::AutoLock lock(&lock_);
   if (id_) {
     if (cmd_buffer_.vmo().is_valid()) {
       auto buffer = static_cast<PipeCmdBuffer*>(cmd_buffer_.start());
       buffer->id = id_;
       buffer->cmd = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kClose);
       buffer->status = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeError::kInval);

       pipe_->Exec(id_);
       ZX_DEBUG_ASSERT(!buffer->status);
     }
     pipe_->Destroy(id_);
   }

   if (binding_ref_) {
     binding_ref_->Unbind();
   }
 }

 void PipeConnection::Init() {
   fbl::AutoLock lock(&lock_);

   zx_status_t status = pipe_->GetBti(&bti_);
   if (status != ZX_OK) {
     FailAsync(status);
     FDF_LOG(ERROR, "[%s] Pipe::Pipe() GetBti failed: %s", kTag, zx_status_get_string(status));
     return;
   }

   status = SetBufferSizeLocked(DEFAULT_BUFFER_SIZE);
   if (status != ZX_OK) {
     FailAsync(status);
     FDF_LOG(ERROR, "[%s] Pipe::Pipe() failed to set initial buffer size: %s", kTag,
             zx_status_get_string(status));
     return;
   }

   zx::event event;
   status = zx::event::create(0, &event);
   if (status != ZX_OK) {
     FailAsync(status);
     FDF_LOG(ERROR, "[%s] Pipe::Pipe() failed to create event: %s", kTag,
             zx_status_get_string(status));
     return;
   }
   status = event.signal(0, SIGNALS);
   ZX_ASSERT(status == ZX_OK);

   zx::vmo vmo;
   status = pipe_->Create(&id_, &vmo);
   if (status != ZX_OK) {
     FailAsync(status);
     FDF_LOG(ERROR, "[%s] Pipe::Pipe() failed to create pipe: %s", kTag,
             zx_status_get_string(status));
     return;
   }

   status = pipe_->SetEvent(id_, std::move(event));
   if (status != ZX_OK) {
     FDF_LOG(ERROR, "[%s] Pipe::Pipe() failed to set event: %s", kTag, zx_status_get_string(status));
     return;
   }

   status =
       cmd_buffer_.Map(std::move(vmo), /*offset=*/0, /*size=*/0, ZX_VM_PERM_READ | ZX_VM_PERM_WRITE);
   if (status != ZX_OK) {
     FailAsync(status);
     FDF_LOG(ERROR, "Failed to map the command buffer VMO: %s", zx_status_get_string(status));
     return;
   }

   auto buffer = static_cast<PipeCmdBuffer*>(cmd_buffer_.start());
   buffer->id = id_;
   buffer->cmd = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kOpen);
   buffer->status = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeError::kInval);

   pipe_->Open(id_);
   if (buffer->status) {
     FailAsync(ZX_ERR_INTERNAL);
     FDF_LOG(ERROR, "[%s] Pipe::Pipe() failed to open pipe", kTag);
     return;
   }
 }

 void PipeConnection::Bind(fidl::ServerEnd<fuchsia_hardware_goldfish::Pipe> server_request) {
   using PipeProtocol = fuchsia_hardware_goldfish::Pipe;
   using PipeServer = fidl::WireServer<PipeProtocol>;
   auto on_unbound = [this](PipeServer*, fidl::UnbindInfo info, fidl::ServerEnd<PipeProtocol>) {
     if (info.is_peer_closed() || info.is_user_initiated()) {
       FDF_LOG(DEBUG, "Pipe closed: %s", info.FormatDescription().c_str());
     } else {
       FDF_LOG(ERROR, "Pipe error: %s", info.FormatDescription().c_str());
     }
     if (on_close_) {
       on_close_(this);
     }
   };

   auto binding =
       fidl::BindServer(dispatcher_, std::move(server_request), this, std::move(on_unbound));
   binding_ref_ =
       std::make_unique<fidl::ServerBindingRef<fuchsia_hardware_goldfish::Pipe>>(std::move(binding));
 }

 void PipeConnection::SetBufferSize(SetBufferSizeRequestView request,
                                    SetBufferSizeCompleter::Sync& completer) {
   TRACE_DURATION("gfx", "Pipe::SetBufferSize", "size", request->size);

   fbl::AutoLock lock(&lock_);

   zx_status_t status = SetBufferSizeLocked(request->size);
   if (status != ZX_OK) {
     FDF_LOG(ERROR, "[%s] Pipe::SetBufferSize() failed to create buffer: %lu", kTag, request->size);
   }

   if (status != ZX_OK && status != ZX_ERR_NO_MEMORY) {
     completer.Close(status);
   } else {
     completer.Reply(status);
   }
 }

 void PipeConnection::SetEvent(SetEventRequestView request, SetEventCompleter::Sync& completer) {
   TRACE_DURATION("gfx", "Pipe::SetEvent");

   if (!request->event.is_valid()) {
     FDF_LOG(ERROR, "[%s] Pipe::SetEvent() invalid event", kTag);
     completer.Close(ZX_ERR_INVALID_ARGS);
     return;
   }

   fbl::AutoLock lock(&lock_);

   zx_status_t status = pipe_->SetEvent(id_, std::move(request->event));
   if (status != ZX_OK) {
     FDF_LOG(ERROR, "[%s] SetEvent failed: %s", kTag, zx_status_get_string(status));
     completer.Close(ZX_ERR_INTERNAL);
     return;
   }
 }

 void PipeConnection::GetBuffer(GetBufferCompleter::Sync& completer) {
   TRACE_DURATION("gfx", "Pipe::GetBuffer");

   fbl::AutoLock lock(&lock_);

   zx::vmo vmo;
   zx_status_t status = buffer_.vmo.duplicate(ZX_RIGHT_SAME_RIGHTS, &vmo);
   if (status != ZX_OK) {
     FDF_LOG(ERROR, "[%s] Pipe::GetBuffer() zx_vmo_duplicate failed: %s", kTag,
             zx_status_get_string(status));
     completer.Close(status);
   } else {
     completer.Reply(ZX_OK, std::move(vmo));
   }
 }

 void PipeConnection::Read(ReadRequestView request, ReadCompleter::Sync& completer) {
   TRACE_DURATION("gfx", "Pipe::Read", "count", request->count);

   fbl::AutoLock lock(&lock_);

   if ((request->offset + request->count) > buffer_.size ||
       (request->offset + request->count) < request->offset) {
     completer.Close(ZX_ERR_INVALID_ARGS);
     return;
   }

   size_t actual;
   zx_status_t status =
       TransferLocked(static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kRead),
                      static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnRead),
                      fuchsia_hardware_goldfish::wire::kSignalReadable,
                      buffer_.phys + request->offset, request->count, 0, 0, &actual);
   completer.Reply(status, actual);
 }

 void PipeConnection::Write(WriteRequestView request, WriteCompleter::Sync& completer) {
   TRACE_DURATION("gfx", "Pipe::Write", "count", request->count);

   fbl::AutoLock lock(&lock_);

   if ((request->offset + request->count) > buffer_.size ||
       (request->offset + request->count) < request->offset) {
     completer.Close(ZX_ERR_INVALID_ARGS);
     return;
   }

   size_t actual;
   zx_status_t status = TransferLocked(
       static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWrite),
       static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnWrite),
       fuchsia_hardware_goldfish::wire::kSignalWritable, buffer_.phys + request->offset,
       request->count, 0, 0, &actual);
   completer.Reply(status, actual);
 }

 void PipeConnection::DoCall(DoCallRequestView request, DoCallCompleter::Sync& completer) {
   TRACE_DURATION("gfx", "Pipe::DoCall", "count", request->count, "read_count", request->read_count);

   fbl::AutoLock lock(&lock_);

   if ((request->offset + request->count) > buffer_.size ||
       (request->offset + request->count) < request->offset) {
     completer.Close(ZX_ERR_INVALID_ARGS);
     return;
   }
   if ((request->read_offset + request->read_count) > buffer_.size ||
       (request->read_offset + request->read_count) < request->read_offset) {
     completer.Close(ZX_ERR_INVALID_ARGS);
     return;
   }

   int32_t cmd = 0, wake_cmd = 0;
   uint32_t wake_signal = 0u;
   zx_paddr_t read_paddr = 0u, write_paddr = 0u;
   // Set write command, signal and offset.
   if (request->count) {
     cmd = request->read_count
               ? static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kCall)
               : static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWrite);
     wake_cmd = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnWrite);
     wake_signal = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnWrite);
     write_paddr = buffer_.phys + request->offset;
   }
   // Set read command, signal and offset.
   if (request->read_count) {
     cmd = request->count ? static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kCall)
                          : static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kRead);
     wake_cmd = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnRead);
     wake_signal = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnRead);
     read_paddr = buffer_.phys + request->read_offset;
   }

   size_t actual = 0u;
   zx_status_t status = TransferLocked(cmd, wake_cmd, wake_signal, write_paddr, request->count,
                                       read_paddr, request->read_count, &actual);

   completer.Reply(status, actual);
 }

 // This function can be trusted to complete fairly quickly. It will cause a
 // VM exit but that should never block for a significant amount of time.
 zx_status_t PipeConnection::TransferLocked(int32_t cmd, int32_t wake_cmd, zx_signals_t state_clr,
                                            zx_paddr_t paddr, size_t count, zx_paddr_t read_paddr,
                                            size_t read_count, size_t* actual) {
   TRACE_DURATION("gfx", "Pipe::Transfer", "count", count, "read_count", read_count);

   auto buffer = static_cast<PipeCmdBuffer*>(cmd_buffer_.start());
   buffer->id = id_;
   buffer->cmd = cmd;
   buffer->status = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeError::kInval);
   buffer->rw_params.ptrs[0] = paddr;
   buffer->rw_params.sizes[0] = static_cast<uint32_t>(count);
   buffer->rw_params.ptrs[1] = read_paddr;
   buffer->rw_params.sizes[1] = static_cast<uint32_t>(read_count);
   buffer->rw_params.buffers_count = read_paddr ? 2 : 1;
   buffer->rw_params.consumed_size = 0;
   buffer->rw_params.read_index = 1;  // Read buffer is always second.
   pipe_->Exec(id_);

   // Positive consumed size always indicate a successful transfer.
   if (buffer->rw_params.consumed_size) {
     *actual = buffer->rw_params.consumed_size;
     return ZX_OK;
   }

   *actual = 0;
   // Early out if error is not because of back-pressure.
   if (buffer->status != static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeError::kAgain)) {
     FDF_LOG(ERROR, "[%s] Pipe::Transfer() transfer failed: %d", kTag, buffer->status);
     return ZX_ERR_INTERNAL;
   }

   buffer->id = id_;
   buffer->cmd = wake_cmd;
   buffer->status = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeError::kInval);
   pipe_->Exec(id_);
   if (buffer->status) {
     FDF_LOG(ERROR, "[%s] Pipe::Transfer() failed to request interrupt: %d", kTag, buffer->status);
     return ZX_ERR_INTERNAL;
   }

   return ZX_ERR_SHOULD_WAIT;
 }

 zx_status_t PipeConnection::SetBufferSizeLocked(size_t size) {
   zx::vmo vmo;
   zx_status_t status = zx::vmo::create_contiguous(bti_, size, 0, &vmo);
   if (status != ZX_OK) {
     FDF_LOG(ERROR, "[%s] Pipe::CreateBuffer() zx_vmo_create_contiguous failed %d size: %zu", kTag,
             status, size);
     return status;
   }

   zx_paddr_t phys;
   zx::pmt pmt;
   // We leave pinned continuously, since buffer is expected to be used frequently.
   status = bti_.pin(ZX_BTI_PERM_READ | ZX_BTI_CONTIGUOUS, vmo, 0, size, &phys, 1, &pmt);
   if (status != ZX_OK) {
     FDF_LOG(ERROR, "[%s] Pipe::CreateBuffer() zx_bti_pin failed %d size: %zu", kTag, status, size);
     return status;
   }

   buffer_ = Buffer{.vmo = std::move(vmo), .pmt = std::move(pmt), .size = size, .phys = phys};
   return ZX_OK;
 }

 void PipeConnection::FailAsync(zx_status_t epitaph) {
   if (binding_ref_) {
     binding_ref_->Close(epitaph);
   }
 }

 PipeConnection::Buffer& PipeConnection::Buffer::operator=(PipeConnection::Buffer&& other) noexcept {
   if (pmt.is_valid()) {
     pmt.unpin();
   }
   vmo = std::move(other.vmo);
   pmt = std::move(other.pmt);
   phys = other.phys;
   size = other.size;
   return *this;
 }

 PipeConnection::Buffer::~Buffer() {
   if (pmt.is_valid()) {
     pmt.unpin();
   }
 }

 }  // namespace goldfish
	// Copyright 2019 The Fuchsia Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include "src/graphics/drivers/misc/goldfish/pipe_connection.h"

	#include <fidl/fuchsia.hardware.goldfish/cpp/wire.h>
	#include <lib/driver/logging/cpp/logger.h>
	#include <lib/fzl/owned-vmo-mapper.h>
	#include <lib/trace/event.h>
	#include <lib/zx/bti.h>
	#include <zircon/status.h>

	#include <fbl/auto_lock.h>

	#include "src/devices/lib/goldfish/pipe_headers/include/base.h"
	#include "src/graphics/drivers/misc/goldfish/pipe_device.h"

	namespace goldfish {
	namespace {

	static const char* kTag = "GoldfishPipe";

	constexpr size_t DEFAULT_BUFFER_SIZE = 8192;

	constexpr zx_signals_t SIGNALS = fuchsia_hardware_goldfish::wire::kSignalReadable \|
	fuchsia_hardware_goldfish::wire::kSignalWritable;

	} // namespace

	PipeConnection::PipeConnection(PipeDevice* pipe, async_dispatcher_t* dispatcher, OnBindFn on_bind,
	OnCloseFn on_close)
	: on_bind_(std::move(on_bind)),
	on_close_(std::move(on_close)),
	dispatcher_(dispatcher),
	pipe_(pipe) {}

	PipeConnection::~PipeConnection() {
	fbl::AutoLock lock(&lock_);
	if (id_) {
	if (cmd_buffer_.vmo().is_valid()) {
	auto buffer = static_cast<PipeCmdBuffer*>(cmd_buffer_.start());
	buffer->id = id_;
	buffer->cmd = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kClose);
	buffer->status = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeError::kInval);

	pipe_->Exec(id_);
	ZX_DEBUG_ASSERT(!buffer->status);
	}
	pipe_->Destroy(id_);
	}

	if (binding_ref_) {
	binding_ref_->Unbind();
	}
	}

	void PipeConnection::Init() {
	fbl::AutoLock lock(&lock_);

	zx_status_t status = pipe_->GetBti(&bti_);
	if (status != ZX_OK) {
	FailAsync(status);
	FDF_LOG(ERROR, "[%s] Pipe::Pipe() GetBti failed: %s", kTag, zx_status_get_string(status));
	return;
	}

	status = SetBufferSizeLocked(DEFAULT_BUFFER_SIZE);
	if (status != ZX_OK) {
	FailAsync(status);
	FDF_LOG(ERROR, "[%s] Pipe::Pipe() failed to set initial buffer size: %s", kTag,
	zx_status_get_string(status));
	return;
	}

	zx::event event;
	status = zx::event::create(0, &event);
	if (status != ZX_OK) {
	FailAsync(status);
	FDF_LOG(ERROR, "[%s] Pipe::Pipe() failed to create event: %s", kTag,
	zx_status_get_string(status));
	return;
	}
	status = event.signal(0, SIGNALS);
	ZX_ASSERT(status == ZX_OK);

	zx::vmo vmo;
	status = pipe_->Create(&id_, &vmo);
	if (status != ZX_OK) {
	FailAsync(status);
	FDF_LOG(ERROR, "[%s] Pipe::Pipe() failed to create pipe: %s", kTag,
	zx_status_get_string(status));
	return;
	}

	status = pipe_->SetEvent(id_, std::move(event));
	if (status != ZX_OK) {
	FDF_LOG(ERROR, "[%s] Pipe::Pipe() failed to set event: %s", kTag, zx_status_get_string(status));
	return;
	}

	status =
	cmd_buffer_.Map(std::move(vmo), /offset=/0, /size=/0, ZX_VM_PERM_READ \| ZX_VM_PERM_WRITE);
	if (status != ZX_OK) {
	FailAsync(status);
	FDF_LOG(ERROR, "Failed to map the command buffer VMO: %s", zx_status_get_string(status));
	return;
	}

	auto buffer = static_cast<PipeCmdBuffer*>(cmd_buffer_.start());
	buffer->id = id_;
	buffer->cmd = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kOpen);
	buffer->status = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeError::kInval);

	pipe_->Open(id_);
	if (buffer->status) {
	FailAsync(ZX_ERR_INTERNAL);
	FDF_LOG(ERROR, "[%s] Pipe::Pipe() failed to open pipe", kTag);
	return;
	}
	}

	void PipeConnection::Bind(fidl::ServerEnd<fuchsia_hardware_goldfish::Pipe> server_request) {
	using PipeProtocol = fuchsia_hardware_goldfish::Pipe;
	using PipeServer = fidl::WireServer<PipeProtocol>;
	auto on_unbound = [this](PipeServer*, fidl::UnbindInfo info, fidl::ServerEnd<PipeProtocol>) {
	if (info.is_peer_closed() \|\| info.is_user_initiated()) {
	FDF_LOG(DEBUG, "Pipe closed: %s", info.FormatDescription().c_str());
	} else {
	FDF_LOG(ERROR, "Pipe error: %s", info.FormatDescription().c_str());
	}
	if (on_close_) {
	on_close_(this);
	}
	};

	auto binding =
	fidl::BindServer(dispatcher_, std::move(server_request), this, std::move(on_unbound));
	binding_ref_ =
	std::make_unique<fidl::ServerBindingRef<fuchsia_hardware_goldfish::Pipe>>(std::move(binding));
	}

	void PipeConnection::SetBufferSize(SetBufferSizeRequestView request,
	SetBufferSizeCompleter::Sync& completer) {
	TRACE_DURATION("gfx", "Pipe::SetBufferSize", "size", request->size);

	fbl::AutoLock lock(&lock_);

	zx_status_t status = SetBufferSizeLocked(request->size);
	if (status != ZX_OK) {
	FDF_LOG(ERROR, "[%s] Pipe::SetBufferSize() failed to create buffer: %lu", kTag, request->size);
	}

	if (status != ZX_OK && status != ZX_ERR_NO_MEMORY) {
	completer.Close(status);
	} else {
	completer.Reply(status);
	}
	}

	void PipeConnection::SetEvent(SetEventRequestView request, SetEventCompleter::Sync& completer) {
	TRACE_DURATION("gfx", "Pipe::SetEvent");

	if (!request->event.is_valid()) {
	FDF_LOG(ERROR, "[%s] Pipe::SetEvent() invalid event", kTag);
	completer.Close(ZX_ERR_INVALID_ARGS);
	return;
	}

	fbl::AutoLock lock(&lock_);

	zx_status_t status = pipe_->SetEvent(id_, std::move(request->event));
	if (status != ZX_OK) {
	FDF_LOG(ERROR, "[%s] SetEvent failed: %s", kTag, zx_status_get_string(status));
	completer.Close(ZX_ERR_INTERNAL);
	return;
	}
	}

	void PipeConnection::GetBuffer(GetBufferCompleter::Sync& completer) {
	TRACE_DURATION("gfx", "Pipe::GetBuffer");

	fbl::AutoLock lock(&lock_);

	zx::vmo vmo;
	zx_status_t status = buffer_.vmo.duplicate(ZX_RIGHT_SAME_RIGHTS, &vmo);
	if (status != ZX_OK) {
	FDF_LOG(ERROR, "[%s] Pipe::GetBuffer() zx_vmo_duplicate failed: %s", kTag,
	zx_status_get_string(status));
	completer.Close(status);
	} else {
	completer.Reply(ZX_OK, std::move(vmo));
	}
	}

	void PipeConnection::Read(ReadRequestView request, ReadCompleter::Sync& completer) {
	TRACE_DURATION("gfx", "Pipe::Read", "count", request->count);

	fbl::AutoLock lock(&lock_);

	if ((request->offset + request->count) > buffer_.size \|\|
	(request->offset + request->count) < request->offset) {
	completer.Close(ZX_ERR_INVALID_ARGS);
	return;
	}

	size_t actual;
	zx_status_t status =
	TransferLocked(static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kRead),
	static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnRead),
	fuchsia_hardware_goldfish::wire::kSignalReadable,
	buffer_.phys + request->offset, request->count, 0, 0, &actual);
	completer.Reply(status, actual);
	}

	void PipeConnection::Write(WriteRequestView request, WriteCompleter::Sync& completer) {
	TRACE_DURATION("gfx", "Pipe::Write", "count", request->count);

	fbl::AutoLock lock(&lock_);

	if ((request->offset + request->count) > buffer_.size \|\|
	(request->offset + request->count) < request->offset) {
	completer.Close(ZX_ERR_INVALID_ARGS);
	return;
	}

	size_t actual;
	zx_status_t status = TransferLocked(
	static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWrite),
	static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnWrite),
	fuchsia_hardware_goldfish::wire::kSignalWritable, buffer_.phys + request->offset,
	request->count, 0, 0, &actual);
	completer.Reply(status, actual);
	}

	void PipeConnection::DoCall(DoCallRequestView request, DoCallCompleter::Sync& completer) {
	TRACE_DURATION("gfx", "Pipe::DoCall", "count", request->count, "read_count", request->read_count);

	fbl::AutoLock lock(&lock_);

	if ((request->offset + request->count) > buffer_.size \|\|
	(request->offset + request->count) < request->offset) {
	completer.Close(ZX_ERR_INVALID_ARGS);
	return;
	}
	if ((request->read_offset + request->read_count) > buffer_.size \|\|
	(request->read_offset + request->read_count) < request->read_offset) {
	completer.Close(ZX_ERR_INVALID_ARGS);
	return;
	}

	int32_t cmd = 0, wake_cmd = 0;
	uint32_t wake_signal = 0u;
	zx_paddr_t read_paddr = 0u, write_paddr = 0u;
	// Set write command, signal and offset.
	if (request->count) {
	cmd = request->read_count
	? static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kCall)
	: static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWrite);
	wake_cmd = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnWrite);
	wake_signal = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnWrite);
	write_paddr = buffer_.phys + request->offset;
	}
	// Set read command, signal and offset.
	if (request->read_count) {
	cmd = request->count ? static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kCall)
	: static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kRead);
	wake_cmd = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnRead);
	wake_signal = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeCmdCode::kWakeOnRead);
	read_paddr = buffer_.phys + request->read_offset;
	}

	size_t actual = 0u;
	zx_status_t status = TransferLocked(cmd, wake_cmd, wake_signal, write_paddr, request->count,
	read_paddr, request->read_count, &actual);

	completer.Reply(status, actual);
	}

	// This function can be trusted to complete fairly quickly. It will cause a
	// VM exit but that should never block for a significant amount of time.
	zx_status_t PipeConnection::TransferLocked(int32_t cmd, int32_t wake_cmd, zx_signals_t state_clr,
	zx_paddr_t paddr, size_t count, zx_paddr_t read_paddr,
	size_t read_count, size_t* actual) {
	TRACE_DURATION("gfx", "Pipe::Transfer", "count", count, "read_count", read_count);

	auto buffer = static_cast<PipeCmdBuffer*>(cmd_buffer_.start());
	buffer->id = id_;
	buffer->cmd = cmd;
	buffer->status = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeError::kInval);
	buffer->rw_params.ptrs[0] = paddr;
	buffer->rw_params.sizes[0] = static_cast<uint32_t>(count);
	buffer->rw_params.ptrs[1] = read_paddr;
	buffer->rw_params.sizes[1] = static_cast<uint32_t>(read_count);
	buffer->rw_params.buffers_count = read_paddr ? 2 : 1;
	buffer->rw_params.consumed_size = 0;
	buffer->rw_params.read_index = 1; // Read buffer is always second.
	pipe_->Exec(id_);

	// Positive consumed size always indicate a successful transfer.
	if (buffer->rw_params.consumed_size) {
	*actual = buffer->rw_params.consumed_size;
	return ZX_OK;
	}

	*actual = 0;
	// Early out if error is not because of back-pressure.
	if (buffer->status != static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeError::kAgain)) {
	FDF_LOG(ERROR, "[%s] Pipe::Transfer() transfer failed: %d", kTag, buffer->status);
	return ZX_ERR_INTERNAL;
	}

	buffer->id = id_;
	buffer->cmd = wake_cmd;
	buffer->status = static_cast<int32_t>(fuchsia_hardware_goldfish_pipe::PipeError::kInval);
	pipe_->Exec(id_);
	if (buffer->status) {
	FDF_LOG(ERROR, "[%s] Pipe::Transfer() failed to request interrupt: %d", kTag, buffer->status);
	return ZX_ERR_INTERNAL;
	}

	return ZX_ERR_SHOULD_WAIT;
	}

	zx_status_t PipeConnection::SetBufferSizeLocked(size_t size) {
	zx::vmo vmo;
	zx_status_t status = zx::vmo::create_contiguous(bti_, size, 0, &vmo);
	if (status != ZX_OK) {
	FDF_LOG(ERROR, "[%s] Pipe::CreateBuffer() zx_vmo_create_contiguous failed %d size: %zu", kTag,
	status, size);
	return status;
	}

	zx_paddr_t phys;
	zx::pmt pmt;
	// We leave pinned continuously, since buffer is expected to be used frequently.
	status = bti_.pin(ZX_BTI_PERM_READ \| ZX_BTI_CONTIGUOUS, vmo, 0, size, &phys, 1, &pmt);
	if (status != ZX_OK) {
	FDF_LOG(ERROR, "[%s] Pipe::CreateBuffer() zx_bti_pin failed %d size: %zu", kTag, status, size);
	return status;
	}

	buffer_ = Buffer{.vmo = std::move(vmo), .pmt = std::move(pmt), .size = size, .phys = phys};
	return ZX_OK;
	}

	void PipeConnection::FailAsync(zx_status_t epitaph) {
	if (binding_ref_) {
	binding_ref_->Close(epitaph);
	}
	}

	PipeConnection::Buffer& PipeConnection::Buffer::operator=(PipeConnection::Buffer&& other) noexcept {
	if (pmt.is_valid()) {
	pmt.unpin();
	}
	vmo = std::move(other.vmo);
	pmt = std::move(other.pmt);
	phys = other.phys;
	size = other.size;
	return *this;
	}

	PipeConnection::Buffer::~Buffer() {
	if (pmt.is_valid()) {
	pmt.unpin();
	}
	}

	} // namespace goldfish