Bsd Now

230: Your questions, Part III

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We provide you with updates to Spectre and Meltdown from various BSD projects, a review of TrueOS from Linux, how to set up FreeBSD on ThinkPad x240, and a whole bunch of beastie bits. This episode was brought to you by Headlines KPTI patch lands in FreeBSD -current (https://svnweb.freebsd.org/base?view=revision&revision=328083) After a heroic effort by Konstantin Belousov kib@FreeBSD.org, the first meltdown patch has landed in FreeBSD This creates separate page tables for the Kernel and userland, and switches between them when executions enters the kernel, and when it returns to userland It is currently off by default, but you are encouraged to test it, so it can be merged back to the release branches. Set vm.pmap.pti=1 in /boot/loader.conf The existing implementation of PCID (process-context identifiers), is not compatible with the new PTI code, and is disabled when PTI is enabled, decreasing performance. A future patch will use PCID in a way that is compatible with PTI. PCID allows the OS to annotate memo