SystemSupportforCustom SpeculationPolicies - PowerPoint PPT Presentation

System
Support
for
Custom Speculation
Policies Benjamin
Wester,
Peter
M.
Chen University
of
Michigan SOSP
2009

Overview App 


App Policy App Policy Speculation Infrastructure Mechanism Benjamin
Wester
‐
University
of
Michigan 2

Speculation
Policy Default Custom • Predict
 system
calls • Predict
 arbitrary
operations • Allow
 no • Allow
 harmless uncommitted
output uncommitted
output • Commit
 identical 
results • Commit
 equivalent 
results • Roll
back
after
any
change • Correction
appropriate
to error Benjamin
Wester
‐
University
of
Michigan 3

Interface Process spec_fork() Speculative
process Controlling
process assume
 x Arbitrary operations allow_fd_output() Define equivalence Set output policy try
to
establish
 x {allow, taint, if (x) commit() defer, block} [else
 rollback() ] Error correction Benjamin
Wester
‐
University
of
Michigan 4

Uses • Predicting
user
actions – Bash
shell • Authentication • User‐level
network
services More? Benjamin
Wester
‐
University
of
Michigan 5