Testing and HW Virtualization (7th White Rabbit Workshop)

Testing and HW Virtualization

Javier Muñoz Mellid & Samuel Iglesias Gonsalvez

7th WhiteRabbit Workshop - November 2012

Agenda

About IgaliaVirtual vs RealLinux support and making of FMC TDC boardTesting, Virtual Hardware and WhiteRabbitTechnical details and demo

Testing and HW Virtualization Javier Muñoz Mellid & Samuel Iglesias Gonsalvez

Who is Igalia?

Free and open software company50 hackers around the globeHacking in different areas

kernelvirtualizationgraphics/renderingcompilersdistros...

www.igalia.com


Virtual vs Real

Using virtual HW is all about having the possibility to testlow level software, such as firmwares, HDL cores orkernel/drivers, without real HW. It is not about replacingreal hardware at all.The idea is analysing every test case on real hardware inorder to know if we can run it on virtual hardware. Thisapproach saves resources and time.


Linux support and making of FMC TDC board


FMC TDC Linux support


FMC TDC Linux support

Time-To-Digital-Converter (TDC) boardUsed for measuring the time of arrival of each incomingpulse in order to save the timestamp into the memory,ready to be read later

CERN/Igalia effort to support FMC-TDC board in Linuxdrivers, user-space library and test cases developed

Integration with ZIO framework, use FMC bus and SPECdrivers


Making of FMC TDC Linux support

We face the typical issues when developing drivers for nonmature hardware

Hardware not availableBuggy firmwares delaying developmentIs it a hardware or software bug? Where is it?Flashing firmware, running tests... are time-intensive tasksHardware specification evolving along the project...


Making of FMC TDC Linux support

In order to minimize the previous issues we explored thevirtual way with the following results ...

No real hardware bottle-neck, parallel developmentNo buggy firmwares issuesGot a virtual baseline in order to test old and newspecifications/firmwares, bug identification really easySaved time in real flashing and testing approachesDeveloped continuous integration and automatic testingtooling for software (kernel, libraries, etc) on top of virtualhardwareGot good-enough virtual models (buses, I/O spaces,memory maps, etc) to cover goals.Further emulation (VHDL, firmware, etc) possible but itwasn’t required for this project


Testing, Virtual Hardware and WhiteRabbit



Some thoughs ...It is not possible catching all bugs in a complex systemA complex system based on hardware/software requiredifferent, but integrated, testing approachesPragmatic testing is a must. Keep all possible testing in thesoft side. It is more affordable, fast and flexibleIt doesn’t matter where the bug is (software or hardware).If it appears in a critical system then it is a critical bugIn the long, continuous integration and automatic testingis the wayFlexible and robust testing approach is key to get greatreleasesAt the end, final testing should always run in the realsystem



Potential WhiteRabbits components to testTools and compilers (ARM, LM32)BuilrootBarebox (bootloader)IPLLinux kernel and drivers (versions, configurations, etc)User space applications (ptpd, hal, libs, etc)VHDL and LM32 binaries



Testing with Virtual Hardware would be possible on thefollowing components

No virtual Hardware requiredTools and compilers (ARM, LM32)Builroot

Virtual Hardware requiredLinux kernel and drivers code (similar FMC TDC approach)LM32 binaries (real-time)VHDL (behaviour)

Not exploredBarebox (bootloader)IPLUser space applications (ptpd, hal, libs, etc)


Technical details and demo


Our work

Virtualized models

Industry PackTEWS TPCI-200.GE IP-OCTAL-232.

FMC TDCSPEC board (only needed bits)FMC TDC board


FMC TDC board


FMC TDC board

It was needed to test error conditions on the driver

Generic stuffThe virtual board in being detected by the driver as agenuine device.Normal mode: no error injection.

DMADMA error: TDC_DMA_STAT_ERR andTDC_DMA_STAT_ABORT.DMA timeout.

Input pulsesFilter events with pulse width lower than 100 ns(requirement).Test different input pulse arrival rate.Test timestamp threshold setup.Test time threshold setup.


What was virtualized?

SPECPCI: (sub)Vendor ID, (sub)Device ID. No MSI support.Memory Map: BAR addresses.

FMC TDC FirmwareMemory map: status and configuration registers, Event’scircular buffer.DMA core: memory map, registers.

Input pulse generationDifferent parameters setup: input pulse arrival rate, pulsewidth, etc.

Error injectionAs it was previously mentioned.


How we did that

QEMU (http://wiki.qemu.org)Open source machine emulator and virtualizer.

Buildbot (http://trac.buildbot.net/)Continuous integration system designed to automate thebuild/test cycle.Python. Web interface to check the logs.

Our own testing suiteBased on Sam’s experience working with PTS in the past.Needed more flexibility: different setups for the same test.Developed in Python, as PTS.


http://wiki.qemu.org

http://trac.buildbot.net/

Testing suite design


Testing suite design

Launch QEMU with some setups:Choose memory size, virtual machine image, network, etc.Snapshot mode.Shared folders to interchange data.No screen.The kernel is pass as a parameter to QEMU -> Not usingthe one in the virtual machine.Timeout. If QEMU is still running after a given time,something wrong happened.Forward kernel logs to QEMU’s serial port. We can readdmesg info from host.


The result (I)


The result (II)


The result (III)


The result (IV)


Potential improvements

Improve the virtual model.Do a more realistic model of the device.Add VHDL virtualization.

QEMU configuration: use config files?Buildbot: fix issues.Testing suite

Add new features (hooks, etc).Choose Red Hat’s autotest framework?



Questions & Answers



Thank you!


Links

http://www.ohwr.org/projects/spec

http://www.ohwr.org/projects/fmc-tdc

http://www.ohwr.org/projects/fmc-tdc-sw

http://blogs.igalia.com/berto/2012/10/03/industrypack-qemu-and-linuxcon/

http://events.linuxfoundation.org/images/stories/pdf/lceu2012_garcia.pdf


http://www.ohwr.org/projects/spec

http://www.ohwr.org/projects/fmc-tdc

http://www.ohwr.org/projects/fmc-tdc-sw





Testing and HW Virtualization (7th White Rabbit Workshop)

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Transcript of Testing and HW Virtualization (7th White Rabbit Workshop)