PVH domains are a new guest type supported by Xen being as lightweight as possible (e.g. no emulation of legacy devices via qemu) while taking advantage of the hardware virtualization features of the x86 processor. As there is no BIOS for a PVH domain booting is a little bit different than for pure hardware virtualized guests. To be able to start such a guest a little shim is needed to gather some information about the environment (especially memory layout) before the standard kernel boot path can be entered. By using a boot loader like grub2 this shim can be avoided as the memory information is already known by grub2 and stored into the so called zeropage according to the multiboot protocol.

Back in the day, I enjoyed coding on 8 bit machines, mostly MSX. There is now a Kickstarted project to create a successor machine with some new features: hardware sprites, hardware scrolling, better sound, integrated SD/MMC IO and an ESP8266 for networking. I will be spending HackWeek 0x10 exploring these new features via Z80 assembly.

The ZSTD is a new compression method, potential replacement for existing methods. The support has been added to linux 4.14, but the bootloader support is missing. Goals:

What if Salt Minions no longer need to specify the IP or DNS address for the Master? Or even better: Master(s) can call minions. Of course, for the beginning, we would assume the network is trusted. But we should be able to add further security checks (keypairs etc). Possible use cases: