src/speed_select.cpp - openbmc/smbios-mdr - Gitiles

 // Copyright (c) 2020 Intel Corporation
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 #include "speed_select.hpp"

 #include "cpuinfo.hpp"
 #include "cpuinfo_utils.hpp"

 #include <peci.h>

 #include <boost/asio/error.hpp>
 #include <boost/asio/steady_timer.hpp>
 #include <xyz/openbmc_project/Common/Device/error.hpp>
 #include <xyz/openbmc_project/Common/error.hpp>
 #include <xyz/openbmc_project/Control/Processor/CurrentOperatingConfig/server.hpp>
 #include <xyz/openbmc_project/Inventory/Item/Cpu/OperatingConfig/server.hpp>

 #include <algorithm>
 #include <iostream>
 #include <memory>
 #include <stdexcept>
 #include <string>

 namespace cpu_info
 {
 namespace sst
 {

 // Specialize char to print the integer value instead of ascii. We basically
 // never want to print a single ascii char.
 std::ostream& operator<<(std::ostream& os, uint8_t value)
 {
     return os << static_cast<int>(value);
 }

 bool checkPECIStatus(EPECIStatus libStatus, uint8_t completionCode)
 {
     if (libStatus != PECI_CC_SUCCESS || completionCode != PECI_DEV_CC_SUCCESS)
     {
         std::cerr << "PECI command failed."
                   << " Driver Status = " << libStatus << ","
                   << " Completion Code = " << completionCode << '\n';
         return false;
     }
     return true;
 }

 std::vector<uint32_t> convertMaskToList(std::bitset<64> mask)
 {
     std::vector<uint32_t> bitList;
     for (size_t i = 0; i < mask.size(); ++i)
     {
         if (mask.test(i))
         {
             bitList.push_back(i);
         }
     }
     return bitList;
 }

 static std::vector<BackendProvider>& getProviders()
 {
     static auto* providers = new std::vector<BackendProvider>;
     return *providers;
 }

 void registerBackend(BackendProvider providerFn)
 {
     getProviders().push_back(providerFn);
 }

 std::unique_ptr<SSTInterface> getInstance(uint8_t address, CPUModel model)
 {
     DEBUG_PRINT << "Searching for provider for " << address << ", model "
                 << std::hex << model << std::dec << '\n';
     for (const auto& provider : getProviders())
     {
         try
         {
             auto interface = provider(address, model);
             DEBUG_PRINT << "returned " << interface << '\n';
             if (interface)
             {
                 return interface;
             }
         }
         catch (...)
         {}
     }
     DEBUG_PRINT << "No supported backends found\n";
     return nullptr;
 }

 using BaseCurrentOperatingConfig =
     sdbusplus::server::object_t<sdbusplus::xyz::openbmc_project::Control::
                                     Processor::server::CurrentOperatingConfig>;

 using BaseOperatingConfig =
     sdbusplus::server::object_t<sdbusplus::xyz::openbmc_project::Inventory::
                                     Item::Cpu::server::OperatingConfig>;

 class OperatingConfig : public BaseOperatingConfig
 {
   public:
     std::string path;
     unsigned int level;

   public:
     using BaseOperatingConfig::BaseOperatingConfig;
     OperatingConfig(sdbusplus::bus_t& bus, unsigned int level_,
                     std::string path_) :
         BaseOperatingConfig(bus, path_.c_str(), action::defer_emit),
         path(std::move(path_)), level(level_)
     {}
 };

 class CPUConfig : public BaseCurrentOperatingConfig
 {
   private:
     /** Objects describing all available SST configs - not modifiable. */
     std::vector<std::unique_ptr<OperatingConfig>> availConfigs;
     sdbusplus::bus_t& bus;
     const uint8_t peciAddress;
     const std::string path; ///< D-Bus path of CPU object
     const CPUModel cpuModel;

     // Keep mutable copies of the properties so we can cache values that we
     // retrieve in the getters. We don't want to throw an error on a D-Bus
     // get-property call (extra error handling in clients), so by caching we can
     // hide any temporary hiccup in PECI communication.
     // These values can be changed by in-band software so we have to do a full
     // PECI read on every get-property, and can't assume that values will change
     // only when set-property is done.
     mutable unsigned int currentLevel;
     mutable bool bfEnabled;

     /**
      * Enforce common pre-conditions for D-Bus set property handlers.
      */
     void setPropertyCheckOrThrow(SSTInterface& sst)
     {
         if (!sst.supportsControl())
         {
             throw sdbusplus::xyz::openbmc_project::Common::Error::NotAllowed();
         }
         if (hostState != HostState::postComplete || !sst.ready())
         {
             throw sdbusplus::xyz::openbmc_project::Common::Error::Unavailable();
         }
     }

   public:
     CPUConfig(sdbusplus::bus_t& bus_, uint8_t index, CPUModel model) :
         BaseCurrentOperatingConfig(bus_, generatePath(index).c_str(),
                                    action::defer_emit),
         bus(bus_), peciAddress(index + MIN_CLIENT_ADDR),
         path(generatePath(index)), cpuModel(model), currentLevel(0),
         bfEnabled(false)
     {}

     //
     // D-Bus Property Overrides
     //

     sdbusplus::message::object_path appliedConfig() const override
     {
         DEBUG_PRINT << "Reading AppliedConfig\n";
         if (hostState != HostState::off)
         {
             // Otherwise, try to read current state
             auto sst = getInstance(peciAddress, cpuModel);
             if (!sst || !sst->ready())
             {
                 std::cerr << __func__
                           << ": Failed to get SST provider instance\n";
             }
             else
             {
                 try
                 {
                     currentLevel = sst->currentLevel();
                 }
                 catch (const PECIError& error)
                 {
                     std::cerr << "Failed to get SST-PP level: " << error.what()
                               << "\n";
                 }
             }
         }
         return generateConfigPath(currentLevel);
     }

     bool baseSpeedPriorityEnabled() const override
     {
         DEBUG_PRINT << "Reading BaseSpeedPriorityEnabled\n";
         if (hostState != HostState::off)
         {
             auto sst = getInstance(peciAddress, cpuModel);
             if (!sst || !sst->ready())
             {
                 std::cerr << __func__
                           << ": Failed to get SST provider instance\n";
             }
             else
             {
                 try
                 {
                     bfEnabled = sst->bfEnabled(currentLevel);
                 }
                 catch (const PECIError& error)
                 {
                     std::cerr << "Failed to get SST-BF status: " << error.what()
                               << "\n";
                 }
             }
         }
         return bfEnabled;
     }

     sdbusplus::message::object_path
         appliedConfig(sdbusplus::message::object_path value) override
     {
         DEBUG_PRINT << "Writing AppliedConfig\n";
         const OperatingConfig* newConfig = nullptr;
         for (const auto& config : availConfigs)
         {
             if (config->path == value.str)
             {
                 newConfig = config.get();
             }
         }

         if (newConfig == nullptr)
         {
             throw sdbusplus::xyz::openbmc_project::Common::Error::
                 InvalidArgument();
         }

         auto sst = getInstance(peciAddress, cpuModel);
         if (!sst)
         {
             std::cerr << __func__ << ": Failed to get SST provider instance\n";
             return sdbusplus::message::object_path();
         }
         setPropertyCheckOrThrow(*sst);
         try
         {
             sst->setCurrentLevel(newConfig->level);
             currentLevel = newConfig->level;
         }
         catch (const PECIError& error)
         {
             std::cerr << "Failed to set new SST-PP level: " << error.what()
                       << "\n";
             throw sdbusplus::xyz::openbmc_project::Common::Device::Error::
                 WriteFailure();
         }

         // return value not used
         return sdbusplus::message::object_path();
     }

     bool baseSpeedPriorityEnabled(bool /* value */) override
     {
         DEBUG_PRINT << "Writing BaseSpeedPriorityEnabled not allowed\n";
         throw sdbusplus::xyz::openbmc_project::Common::Error::NotAllowed();
         // return value not used
         return false;
     }

     //
     // Additions
     //

     OperatingConfig& newConfig(unsigned int level)
     {
         availConfigs.emplace_back(std::make_unique<OperatingConfig>(
             bus, level, generateConfigPath(level)));
         return *availConfigs.back();
     }

     std::string generateConfigPath(unsigned int level) const
     {
         return path + "/config" + std::to_string(level);
     }

     /**
      * Emit the interface added signals which were deferred. This is required
      * for ObjectMapper to pick up the objects, if we initially defered the
      * signal emitting.
      */
     void finalize()
     {
         emit_added();
         for (auto& config : availConfigs)
         {
             config->emit_added();
         }
     }

     static std::string generatePath(int index)
     {
         return cpuPath + std::to_string(index);
     }
 };

 /**
  * Retrieve the SST parameters for a single config and fill the values into the
  * properties on the D-Bus interface.
  *
  * @param[in,out]   sst         Interface to SST backend.
  * @param[in]       level       Config TDP level to retrieve.
  * @param[out]      config      D-Bus interface to update.
  */
 static void getSingleConfig(SSTInterface& sst, unsigned int level,
                             OperatingConfig& config)
 {
     config.powerLimit(sst.tdp(level));
     DEBUG_PRINT << " TDP = " << config.powerLimit() << '\n';

     config.availableCoreCount(sst.coreCount(level));
     DEBUG_PRINT << " coreCount = " << config.availableCoreCount() << '\n';

     config.baseSpeed(sst.p1Freq(level));
     DEBUG_PRINT << " baseSpeed = " << config.baseSpeed() << '\n';

     config.maxSpeed(sst.p0Freq(level));
     DEBUG_PRINT << " maxSpeed = " << config.maxSpeed() << '\n';

     config.maxJunctionTemperature(sst.prochotTemp(level));
     DEBUG_PRINT << " procHot = " << config.maxJunctionTemperature() << '\n';

     // Construct BaseSpeedPrioritySettings
     std::vector<std::tuple<uint32_t, std::vector<uint32_t>>> baseSpeeds;
     if (sst.bfSupported(level))
     {
         std::vector<uint32_t> totalCoreList, loFreqCoreList, hiFreqCoreList;
         totalCoreList = sst.enabledCoreList(level);
         hiFreqCoreList = sst.bfHighPriorityCoreList(level);
         std::set_difference(
             totalCoreList.begin(), totalCoreList.end(), hiFreqCoreList.begin(),
             hiFreqCoreList.end(),
             std::inserter(loFreqCoreList, loFreqCoreList.begin()));

         baseSpeeds = {{sst.bfHighPriorityFreq(level), hiFreqCoreList},
                       {sst.bfLowPriorityFreq(level), loFreqCoreList}};
     }
     config.baseSpeedPrioritySettings(baseSpeeds);

     config.turboProfile(sst.sseTurboProfile(level));
 }

 /**
  * Retrieve all SST configuration info for all discoverable CPUs, and publish
  * the info on new D-Bus objects on the given bus connection.
  *
  * @param[in,out]   ioc     ASIO context.
  * @param[in,out]   conn    D-Bus ASIO connection.
  *
  * @return  Whether discovery was successfully finished.
  *
  * @throw PECIError     A PECI command failed on a CPU which had previously
  *                      responded to a command.
  */
 static bool discoverCPUsAndConfigs(boost::asio::io_context& ioc,
                                    sdbusplus::asio::connection& conn)
 {
     // Persistent list - only populated after complete/successful discovery
     static std::vector<std::unique_ptr<CPUConfig>> cpus;
     cpus.clear();

     // Temporary staging list. In case there is any failure, these temporary
     // objects will get dropped to avoid presenting incomplete info until the
     // next discovery attempt.
     std::vector<std::unique_ptr<CPUConfig>> cpuList;

     for (uint8_t i = MIN_CLIENT_ADDR; i <= MAX_CLIENT_ADDR; ++i)
     {
         // Let the event handler run any waiting tasks. If there is a lot of
         // PECI contention, SST discovery could take a long time. This lets us
         // get updates to hostState and handle any D-Bus requests.
         ioc.poll();

         if (hostState == HostState::off)
         {
             return false;
         }

         unsigned int cpuIndex = i - MIN_CLIENT_ADDR;
         DEBUG_PRINT << "Discovering CPU " << cpuIndex << '\n';

         // We could possibly check D-Bus for CPU presence and model, but PECI is
         // 10x faster and so much simpler.
         uint8_t cc, stepping;
         CPUModel cpuModel;
         EPECIStatus status = peci_GetCPUID(i, &cpuModel, &stepping, &cc);
         if (status == PECI_CC_TIMEOUT)
         {
             // Timing out indicates the CPU is present but PCS services not
             // working yet. Try again later.
             throw PECIError("Get CPUID timed out");
         }
         if (status == PECI_CC_CPU_NOT_PRESENT)
         {
             continue;
         }
         if (status != PECI_CC_SUCCESS || cc != PECI_DEV_CC_SUCCESS)
         {
             std::cerr << "GetCPUID returned status " << status
                       << ", cc = " << cc << '\n';
             continue;
         }

         std::unique_ptr<SSTInterface> sst = getInstance(i, cpuModel);

         if (!sst)
         {
             // No supported backend for this CPU.
             continue;
         }

         if (!sst->ready())
         {
             // Supported CPU but it can't be queried yet. Try again later.
             std::cerr << "sst not ready yet\n";
             return false;
         }

         if (!sst->ppEnabled())
         {
             // Supported CPU but the specific SKU doesn't support SST-PP.
             std::cerr << "CPU doesn't support SST-PP\n";
             continue;
         }

         // Create the per-CPU configuration object
         cpuList.emplace_back(
             std::make_unique<CPUConfig>(conn, cpuIndex, cpuModel));
         CPUConfig& cpu = *cpuList.back();

         bool foundCurrentLevel = false;

         for (unsigned int level = 0; level <= sst->maxLevel(); ++level)
         {
             DEBUG_PRINT << "checking level " << level << ": ";
             // levels 1 and 2 were legacy/deprecated, originally used for AVX
             // license pre-granting. They may be reused for more levels in
             // future generations. So we need to check for discontinuities.
             if (!sst->levelSupported(level))
             {
                 DEBUG_PRINT << "not supported\n";
                 continue;
             }

             DEBUG_PRINT << "supported\n";

             getSingleConfig(*sst, level, cpu.newConfig(level));

             if (level == sst->currentLevel())
             {
                 foundCurrentLevel = true;
             }
         }

         DEBUG_PRINT << "current level is " << sst->currentLevel() << '\n';

         if (!foundCurrentLevel)
         {
             // In case we didn't encounter a PECI error, but also didn't find
             // the config which is supposedly applied, we won't be able to
             // populate the CurrentOperatingConfig so we have to remove this CPU
             // from consideration.
             std::cerr << "CPU " << cpuIndex
                       << " claimed SST support but invalid configs\n";
             cpuList.pop_back();
             continue;
         }
     }

     cpuList.swap(cpus);
     std::for_each(cpus.begin(), cpus.end(), [](auto& cpu) { cpu->finalize(); });
     return true;
 }

 /**
  * Attempt discovery process, and if it fails, wait for 10 seconds to try again.
  */
 static void discoverOrWait()
 {
     static boost::asio::steady_timer peciRetryTimer(dbus::getIOContext());
     static int peciErrorCount = 0;
     bool finished = false;

     // This function may be called from hostStateHandler or by retrying itself.
     // In case those overlap, cancel any outstanding retry timer.
     peciRetryTimer.cancel();

     try
     {
         DEBUG_PRINT << "Starting discovery\n";
         finished = discoverCPUsAndConfigs(dbus::getIOContext(),
                                           *dbus::getConnection());
     }
     catch (const PECIError& err)
     {
         std::cerr << "PECI Error: " << err.what() << '\n';

         // In case of repeated failure to finish discovery, turn off this
         // feature altogether. Possible cause is that the CPU model does not
         // actually support the necessary commands.
         if (++peciErrorCount >= 50)
         {
             std::cerr << "Aborting SST discovery\n";
             return;
         }

         std::cerr << "Retrying SST discovery later\n";
     }

     DEBUG_PRINT << "Finished discovery attempt: " << finished << '\n';

     // Retry later if no CPUs were available, or there was a PECI error.
     if (!finished)
     {
         peciRetryTimer.expires_after(std::chrono::seconds(10));
         peciRetryTimer.async_wait([](boost::system::error_code ec) {
             if (ec)
             {
                 if (ec != boost::asio::error::operation_aborted)
                 {
                     std::cerr << "SST PECI Retry Timer failed: " << ec << '\n';
                 }
                 return;
             }
             discoverOrWait();
         });
     }
 }

 static void hostStateHandler(HostState prevState, HostState)
 {
     if (prevState == HostState::off)
     {
         // Start or re-start discovery any time the host moves out of the
         // powered off state.
         discoverOrWait();
     }
 }

 void init()
 {
     addHostStateCallback(hostStateHandler);
 }

 } // namespace sst
 } // namespace cpu_info
	// Copyright (c) 2020 Intel Corporation
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	#include "speed_select.hpp"

	#include "cpuinfo.hpp"
	#include "cpuinfo_utils.hpp"

	#include <peci.h>

	#include <boost/asio/error.hpp>
	#include <boost/asio/steady_timer.hpp>
	#include <xyz/openbmc_project/Common/Device/error.hpp>
	#include <xyz/openbmc_project/Common/error.hpp>
	#include <xyz/openbmc_project/Control/Processor/CurrentOperatingConfig/server.hpp>
	#include <xyz/openbmc_project/Inventory/Item/Cpu/OperatingConfig/server.hpp>

	#include <algorithm>
	#include <iostream>
	#include <memory>
	#include <stdexcept>
	#include <string>

	namespace cpu_info
	{
	namespace sst
	{

	// Specialize char to print the integer value instead of ascii. We basically
	// never want to print a single ascii char.
	std::ostream& operator<<(std::ostream& os, uint8_t value)
	{
	return os << static_cast<int>(value);
	}

	bool checkPECIStatus(EPECIStatus libStatus, uint8_t completionCode)
	{
	if (libStatus != PECI_CC_SUCCESS \|\| completionCode != PECI_DEV_CC_SUCCESS)
	{
	std::cerr << "PECI command failed."
	<< " Driver Status = " << libStatus << ","
	<< " Completion Code = " << completionCode << '\n';
	return false;
	}
	return true;
	}

	std::vector<uint32_t> convertMaskToList(std::bitset<64> mask)
	{
	std::vector<uint32_t> bitList;
	for (size_t i = 0; i < mask.size(); ++i)
	{
	if (mask.test(i))
	{
	bitList.push_back(i);
	}
	}
	return bitList;
	}

	static std::vector<BackendProvider>& getProviders()
	{
	static auto* providers = new std::vector<BackendProvider>;
	return *providers;
	}

	void registerBackend(BackendProvider providerFn)
	{
	getProviders().push_back(providerFn);
	}

	std::unique_ptr<SSTInterface> getInstance(uint8_t address, CPUModel model)
	{
	DEBUG_PRINT << "Searching for provider for " << address << ", model "
	<< std::hex << model << std::dec << '\n';
	for (const auto& provider : getProviders())
	{
	try
	{
	auto interface = provider(address, model);
	DEBUG_PRINT << "returned " << interface << '\n';
	if (interface)
	{
	return interface;
	}
	}
	catch (...)
	{}
	}
	DEBUG_PRINT << "No supported backends found\n";
	return nullptr;
	}

	using BaseCurrentOperatingConfig =
	sdbusplus::server::object_t<sdbusplus::xyz::openbmc_project::Control::
	Processor::server::CurrentOperatingConfig>;

	using BaseOperatingConfig =
	sdbusplus::server::object_t<sdbusplus::xyz::openbmc_project::Inventory::
	Item::Cpu::server::OperatingConfig>;

	class OperatingConfig : public BaseOperatingConfig
	{
	public:
	std::string path;
	unsigned int level;

	public:
	using BaseOperatingConfig::BaseOperatingConfig;
	OperatingConfig(sdbusplus::bus_t& bus, unsigned int level_,
	std::string path_) :
	BaseOperatingConfig(bus, path_.c_str(), action::defer_emit),
	path(std::move(path_)), level(level_)
	{}
	};

	class CPUConfig : public BaseCurrentOperatingConfig
	{
	private:
	/** Objects describing all available SST configs - not modifiable. */
	std::vector<std::unique_ptr<OperatingConfig>> availConfigs;
	sdbusplus::bus_t& bus;
	const uint8_t peciAddress;
	const std::string path; ///< D-Bus path of CPU object
	const CPUModel cpuModel;

	// Keep mutable copies of the properties so we can cache values that we
	// retrieve in the getters. We don't want to throw an error on a D-Bus
	// get-property call (extra error handling in clients), so by caching we can
	// hide any temporary hiccup in PECI communication.
	// These values can be changed by in-band software so we have to do a full
	// PECI read on every get-property, and can't assume that values will change
	// only when set-property is done.
	mutable unsigned int currentLevel;
	mutable bool bfEnabled;

	/**
	* Enforce common pre-conditions for D-Bus set property handlers.
	*/
	void setPropertyCheckOrThrow(SSTInterface& sst)
	{
	if (!sst.supportsControl())
	{
	throw sdbusplus::xyz::openbmc_project::Common::Error::NotAllowed();
	}
	if (hostState != HostState::postComplete \|\| !sst.ready())
	{
	throw sdbusplus::xyz::openbmc_project::Common::Error::Unavailable();
	}
	}

	public:
	CPUConfig(sdbusplus::bus_t& bus_, uint8_t index, CPUModel model) :
	BaseCurrentOperatingConfig(bus_, generatePath(index).c_str(),
	action::defer_emit),
	bus(bus_), peciAddress(index + MIN_CLIENT_ADDR),
	path(generatePath(index)), cpuModel(model), currentLevel(0),
	bfEnabled(false)
	{}

	//
	// D-Bus Property Overrides
	//

	sdbusplus::message::object_path appliedConfig() const override
	{
	DEBUG_PRINT << "Reading AppliedConfig\n";
	if (hostState != HostState::off)
	{
	// Otherwise, try to read current state
	auto sst = getInstance(peciAddress, cpuModel);
	if (!sst \|\| !sst->ready())
	{
	std::cerr << __func__
	<< ": Failed to get SST provider instance\n";
	}
	else
	{
	try
	{
	currentLevel = sst->currentLevel();
	}
	catch (const PECIError& error)
	{
	std::cerr << "Failed to get SST-PP level: " << error.what()
	<< "\n";
	}
	}
	}
	return generateConfigPath(currentLevel);
	}

	bool baseSpeedPriorityEnabled() const override
	{
	DEBUG_PRINT << "Reading BaseSpeedPriorityEnabled\n";
	if (hostState != HostState::off)
	{
	auto sst = getInstance(peciAddress, cpuModel);
	if (!sst \|\| !sst->ready())
	{
	std::cerr << __func__
	<< ": Failed to get SST provider instance\n";
	}
	else
	{
	try
	{
	bfEnabled = sst->bfEnabled(currentLevel);
	}
	catch (const PECIError& error)
	{
	std::cerr << "Failed to get SST-BF status: " << error.what()
	<< "\n";
	}
	}
	}
	return bfEnabled;
	}

	sdbusplus::message::object_path
	appliedConfig(sdbusplus::message::object_path value) override
	{
	DEBUG_PRINT << "Writing AppliedConfig\n";
	const OperatingConfig* newConfig = nullptr;
	for (const auto& config : availConfigs)
	{
	if (config->path == value.str)
	{
	newConfig = config.get();
	}
	}

	if (newConfig == nullptr)
	{
	throw sdbusplus::xyz::openbmc_project::Common::Error::
	InvalidArgument();
	}

	auto sst = getInstance(peciAddress, cpuModel);
	if (!sst)
	{
	std::cerr << __func__ << ": Failed to get SST provider instance\n";
	return sdbusplus::message::object_path();
	}
	setPropertyCheckOrThrow(*sst);
	try
	{
	sst->setCurrentLevel(newConfig->level);
	currentLevel = newConfig->level;
	}
	catch (const PECIError& error)
	{
	std::cerr << "Failed to set new SST-PP level: " << error.what()
	<< "\n";
	throw sdbusplus::xyz::openbmc_project::Common::Device::Error::
	WriteFailure();
	}

	// return value not used
	return sdbusplus::message::object_path();
	}

	bool baseSpeedPriorityEnabled(bool /* value */) override
	{
	DEBUG_PRINT << "Writing BaseSpeedPriorityEnabled not allowed\n";
	throw sdbusplus::xyz::openbmc_project::Common::Error::NotAllowed();
	// return value not used
	return false;
	}

	//
	// Additions
	//

	OperatingConfig& newConfig(unsigned int level)
	{
	availConfigs.emplace_back(std::make_unique<OperatingConfig>(
	bus, level, generateConfigPath(level)));
	return *availConfigs.back();
	}

	std::string generateConfigPath(unsigned int level) const
	{
	return path + "/config" + std::to_string(level);
	}

	/**
	* Emit the interface added signals which were deferred. This is required
	* for ObjectMapper to pick up the objects, if we initially defered the
	* signal emitting.
	*/
	void finalize()
	{
	emit_added();
	for (auto& config : availConfigs)
	{
	config->emit_added();
	}
	}

	static std::string generatePath(int index)
	{
	return cpuPath + std::to_string(index);
	}
	};

	/**
	* Retrieve the SST parameters for a single config and fill the values into the
	* properties on the D-Bus interface.
	*
	* @param[in,out] sst Interface to SST backend.
	* @param[in] level Config TDP level to retrieve.
	* @param[out] config D-Bus interface to update.
	*/
	static void getSingleConfig(SSTInterface& sst, unsigned int level,
	OperatingConfig& config)
	{
	config.powerLimit(sst.tdp(level));
	DEBUG_PRINT << " TDP = " << config.powerLimit() << '\n';

	config.availableCoreCount(sst.coreCount(level));
	DEBUG_PRINT << " coreCount = " << config.availableCoreCount() << '\n';

	config.baseSpeed(sst.p1Freq(level));
	DEBUG_PRINT << " baseSpeed = " << config.baseSpeed() << '\n';

	config.maxSpeed(sst.p0Freq(level));
	DEBUG_PRINT << " maxSpeed = " << config.maxSpeed() << '\n';

	config.maxJunctionTemperature(sst.prochotTemp(level));
	DEBUG_PRINT << " procHot = " << config.maxJunctionTemperature() << '\n';

	// Construct BaseSpeedPrioritySettings
	std::vector<std::tuple<uint32_t, std::vector<uint32_t>>> baseSpeeds;
	if (sst.bfSupported(level))
	{
	std::vector<uint32_t> totalCoreList, loFreqCoreList, hiFreqCoreList;
	totalCoreList = sst.enabledCoreList(level);
	hiFreqCoreList = sst.bfHighPriorityCoreList(level);
	std::set_difference(
	totalCoreList.begin(), totalCoreList.end(), hiFreqCoreList.begin(),
	hiFreqCoreList.end(),
	std::inserter(loFreqCoreList, loFreqCoreList.begin()));

	baseSpeeds = {{sst.bfHighPriorityFreq(level), hiFreqCoreList},
	{sst.bfLowPriorityFreq(level), loFreqCoreList}};
	}
	config.baseSpeedPrioritySettings(baseSpeeds);

	config.turboProfile(sst.sseTurboProfile(level));
	}

	/**
	* Retrieve all SST configuration info for all discoverable CPUs, and publish
	* the info on new D-Bus objects on the given bus connection.
	*
	* @param[in,out] ioc ASIO context.
	* @param[in,out] conn D-Bus ASIO connection.
	*
	* @return Whether discovery was successfully finished.
	*
	* @throw PECIError A PECI command failed on a CPU which had previously
	* responded to a command.
	*/
	static bool discoverCPUsAndConfigs(boost::asio::io_context& ioc,
	sdbusplus::asio::connection& conn)
	{
	// Persistent list - only populated after complete/successful discovery
	static std::vector<std::unique_ptr<CPUConfig>> cpus;
	cpus.clear();

	// Temporary staging list. In case there is any failure, these temporary
	// objects will get dropped to avoid presenting incomplete info until the
	// next discovery attempt.
	std::vector<std::unique_ptr<CPUConfig>> cpuList;

	for (uint8_t i = MIN_CLIENT_ADDR; i <= MAX_CLIENT_ADDR; ++i)
	{
	// Let the event handler run any waiting tasks. If there is a lot of
	// PECI contention, SST discovery could take a long time. This lets us
	// get updates to hostState and handle any D-Bus requests.
	ioc.poll();

	if (hostState == HostState::off)
	{
	return false;
	}

	unsigned int cpuIndex = i - MIN_CLIENT_ADDR;
	DEBUG_PRINT << "Discovering CPU " << cpuIndex << '\n';

	// We could possibly check D-Bus for CPU presence and model, but PECI is
	// 10x faster and so much simpler.
	uint8_t cc, stepping;
	CPUModel cpuModel;
	EPECIStatus status = peci_GetCPUID(i, &cpuModel, &stepping, &cc);
	if (status == PECI_CC_TIMEOUT)
	{
	// Timing out indicates the CPU is present but PCS services not
	// working yet. Try again later.
	throw PECIError("Get CPUID timed out");
	}
	if (status == PECI_CC_CPU_NOT_PRESENT)
	{
	continue;
	}
	if (status != PECI_CC_SUCCESS \|\| cc != PECI_DEV_CC_SUCCESS)
	{
	std::cerr << "GetCPUID returned status " << status
	<< ", cc = " << cc << '\n';
	continue;
	}

	std::unique_ptr<SSTInterface> sst = getInstance(i, cpuModel);

	if (!sst)
	{
	// No supported backend for this CPU.
	continue;
	}

	if (!sst->ready())
	{
	// Supported CPU but it can't be queried yet. Try again later.
	std::cerr << "sst not ready yet\n";
	return false;
	}

	if (!sst->ppEnabled())
	{
	// Supported CPU but the specific SKU doesn't support SST-PP.
	std::cerr << "CPU doesn't support SST-PP\n";
	continue;
	}

	// Create the per-CPU configuration object
	cpuList.emplace_back(
	std::make_unique<CPUConfig>(conn, cpuIndex, cpuModel));
	CPUConfig& cpu = *cpuList.back();

	bool foundCurrentLevel = false;

	for (unsigned int level = 0; level <= sst->maxLevel(); ++level)
	{
	DEBUG_PRINT << "checking level " << level << ": ";
	// levels 1 and 2 were legacy/deprecated, originally used for AVX
	// license pre-granting. They may be reused for more levels in
	// future generations. So we need to check for discontinuities.
	if (!sst->levelSupported(level))
	{
	DEBUG_PRINT << "not supported\n";
	continue;
	}

	DEBUG_PRINT << "supported\n";

	getSingleConfig(*sst, level, cpu.newConfig(level));

	if (level == sst->currentLevel())
	{
	foundCurrentLevel = true;
	}
	}

	DEBUG_PRINT << "current level is " << sst->currentLevel() << '\n';

	if (!foundCurrentLevel)
	{
	// In case we didn't encounter a PECI error, but also didn't find
	// the config which is supposedly applied, we won't be able to
	// populate the CurrentOperatingConfig so we have to remove this CPU
	// from consideration.
	std::cerr << "CPU " << cpuIndex
	<< " claimed SST support but invalid configs\n";
	cpuList.pop_back();
	continue;
	}
	}

	cpuList.swap(cpus);
	std::for_each(cpus.begin(), cpus.end(), [](auto& cpu) { cpu->finalize(); });
	return true;
	}

	/**
	* Attempt discovery process, and if it fails, wait for 10 seconds to try again.
	*/
	static void discoverOrWait()
	{
	static boost::asio::steady_timer peciRetryTimer(dbus::getIOContext());
	static int peciErrorCount = 0;
	bool finished = false;

	// This function may be called from hostStateHandler or by retrying itself.
	// In case those overlap, cancel any outstanding retry timer.
	peciRetryTimer.cancel();

	try
	{
	DEBUG_PRINT << "Starting discovery\n";
	finished = discoverCPUsAndConfigs(dbus::getIOContext(),
	*dbus::getConnection());
	}
	catch (const PECIError& err)
	{
	std::cerr << "PECI Error: " << err.what() << '\n';

	// In case of repeated failure to finish discovery, turn off this
	// feature altogether. Possible cause is that the CPU model does not
	// actually support the necessary commands.
	if (++peciErrorCount >= 50)
	{
	std::cerr << "Aborting SST discovery\n";
	return;
	}

	std::cerr << "Retrying SST discovery later\n";
	}

	DEBUG_PRINT << "Finished discovery attempt: " << finished << '\n';

	// Retry later if no CPUs were available, or there was a PECI error.
	if (!finished)
	{
	peciRetryTimer.expires_after(std::chrono::seconds(10));
	peciRetryTimer.async_wait([](boost::system::error_code ec) {
	if (ec)
	{
	if (ec != boost::asio::error::operation_aborted)
	{
	std::cerr << "SST PECI Retry Timer failed: " << ec << '\n';
	}
	return;
	}
	discoverOrWait();
	});
	}
	}

	static void hostStateHandler(HostState prevState, HostState)
	{
	if (prevState == HostState::off)
	{
	// Start or re-start discovery any time the host moves out of the
	// powered off state.
	discoverOrWait();
	}
	}

	void init()
	{
	addHostStateCallback(hostStateHandler);
	}

	} // namespace sst
	} // namespace cpu_info