[lkml]   [2018]   [Oct]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC 00/60] Coscheduling for Linux
On 9/7/18 5:39 PM, Jan H. Schönherr wrote:

> The collective context switch from one coscheduled set of tasks to another
> -- while fast -- is not atomic. If a use-case needs the absolute guarantee
> that all tasks of the previous set have stopped executing before any task
> of the next set starts executing, an additional hand-shake/barrier needs to
> be added.

In case nobody else brought it up yet, you're going to need a handshake
to strengthen protection against L1TF attacks. Otherwise, there's still
a small window where an attack can occur during the reschedule. Perhaps
one could then cause this to happen artificially by repeatedly have a VM
do some kind of pause/mwait type operation that might do a reschedule.


Computer Architect | Sent with my Fedora powered laptop

 \ /
  Last update: 2018-10-04 15:31    [W:0.372 / U:2.516 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site