Planet Hypervisor

MirageOS security advisory 00: mirage-net-xen

MirageOS Security Advisory 00 - memory disclosure in mirage-net-xen Module: mirage-net-xenAnnounced: 2016-05-03Credits: Enguerrand Decorne, Thomas Leonard, Hannes Mehnert, Mindy PrestonAffects: mirage-net-xen

I'm part of Conservancy's GPL Compliance Project for Linux

I am one of the Linux copyright holders who has signed an agreement for the Software Freedom Conservancy to enforce the GPL on my behalf, as part of the Conservancy's GPL Compliance Project For Linux Developers. I’m also a financial supporter of Conservancy. We're a group of Linux kernel developers that give input and guidance on Conservancy's strategy in dealing with compliance issues on the Linux kernel.I don't take this lightly"Don't be evil" is hardWhy things are hairy when it comes to the Linux kernel and GPL enforcementWhy we need GPL enforcementHow can we enforce the GPL responsiblyEvolving copyleftI don't take...

Introducing Functoria

For the last few months, I've been working with Thomas on improving the mirage tool and I'm happy to present Functoria, a library to create arbitrary MirageOS-like DSLs. Functoria is independent from mirage and will replace the core engine, which was somewhat bolted on to the tool until now. This introduces a few breaking changes so please consult the breaking changes page to see what is different and how to fix things if needed. The good news is that it will be much more simple to use, much more flexible, and will even produce pretty pictures! Configuration For people unfamiliar with MirageOS, the mirage tool handles configuration...

Hotswapping a failed RAID device

Recently I started getting SMART warnings from on of the disks in my home NAS (a QNAP TS-419P II armel/kirkwood device running Debian Jessie): Device: /dev/disk/by-id/ata-ST3000DM001-1CH166_W1F2QSV6 [SAT], Self-Test Log error count increased from to 1 Meaning it was now time to switch out that disk from the RAID5 array. Since everytime this happens I have to go and lookup again what to do I've decided to write it down this time. I configure SMART to talk about devices by-id (giving me their name and model number) so first I needed to figure out what the kernel was calling this device (although mdadm is happy with the by-id...

ZFS, Linux, illumos and the ISC license

People are discussing whether or not Canonical including and shipping ZFS as a Linux kernel module of the GPLv2 licensed Linux kernel might be a GPL violation or not. James Bottomley recently posted an interesting opinion in that although it is a technical GPL violation "it’s difficult to develop a theory of harm and thus the combination is allowable" given that you'd need to prove the harm is done to prosecute. Meanwhile just today Conservancy has released a Statement on ZFS and Linux combinations. In it are very important pieces of information on serious incompatibilities which takes this a bit further outside...

Support software freedom now!

Free Software is in a critical state today. Bradley Kuhn recently has made an urgent call for supports of free software to help a campaign to strengthen both the Free Software Foundation and Software Freedom Conservancy, specially given if you donate before January 31st 2016 as your donation will be matched! I've learned the hard way that without such organizations we could be in for a dark age on user software freedoms. No other entity is doing what they do and they are both of critical importance to the community. Because of this I'm not only contributing now but I've...

Training neural network using genetic algorithm

Over the last few years we observed the raise of artificially intelligent applications, which showed almost super-human ability to solve difficult problems. A closer look reveals that deep neural networks is what drives this wave.

Why open hardware must succeed

To the average person open hardware simply sounds like a good idea... They may have heard of this thing called "open source" that some "disruptive" hipster companies may have used and embraced to create new business models, so open source hardware seems like a natural progression. There's more to this though. The average person will not understand why its not just a great idea but also that we are in dire need for open hardware in the industry, the average person will not understand why its vital to the success of the open source movement. The average person will not...

XSAVE bug discovered for Skylake cpu

At first, serial console put us behind the schedule. As it was very unusual problem due to malfunctioned serial cable. And now some another bug has cost us some very precious time. The anomaly started while I was trying to boot Xen on my system, I found Xen stuck in an infinite loop of the […]

Xen and the x86 Linux zero page

This is part II, for part I - refer to "Avoiding dead code: pv_ops is not the silver bullet".On x86 Linux the boot sequence is rather complicated, so much so that it has its own dedicated boot protocol. This is documented upstream on Documentation/x86/boot.txt. The protocol tends to evolve as the x86 architecture evolves, in order to compensate for new features or extensions which could we need to learn about at boot time. Of interest to this post is the "zero page". The first step when loading a Linux kernel is to load the "zero page", this consists of a...