Messages in this thread | | | Date | Wed, 31 Jan 2018 07:24:49 -0600 | From | Josh Poimboeuf <> | Subject | Re: [tip:x86/pti] x86/speculation: Use Indirect Branch Prediction Barrier in context switch |
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On Wed, Jan 31, 2018 at 08:03:00AM +0100, Dominik Brodowski wrote: > On Tue, Jan 30, 2018 at 02:39:45PM -0800, tip-bot for Tim Chen wrote: > > Commit-ID: 18bf3c3ea8ece8f03b6fc58508f2dfd23c7711c7 > > Gitweb: https://git.kernel.org/tip/18bf3c3ea8ece8f03b6fc58508f2dfd23c7711c7 > > Author: Tim Chen <tim.c.chen@linux.intel.com> > > AuthorDate: Mon, 29 Jan 2018 22:04:47 +0000 > > Committer: Thomas Gleixner <tglx@linutronix.de> > > CommitDate: Tue, 30 Jan 2018 23:09:21 +0100 > > > > x86/speculation: Use Indirect Branch Prediction Barrier in context switch > > > > Flush indirect branches when switching into a process that marked itself > > non dumpable. This protects high value processes like gpg better, > > without having too high performance overhead. > > For the record, I am still opposed to limit this to non-dumpable processes. > Whether a process needs protection by IBPB on context switches is a > different question to whether a process should be allowed to be dumped, > though the former may be a superset of the latter. In my opinion, IBPB > should be enabled on all context switches to userspace processes, until we > have a clear mitigation strategy for userspace against Spectre-v2 designed > and implemented. > > Thanks, > Dominik > > -------------------------- > From: Dominik Brodowski <linux@dominikbrodowski.net> > Date: Wed, 31 Jan 2018 07:43:12 +0100 > Subject: [PATCH] x86/speculation: Do not limit Indirect Branch Prediction Barrier to non-dumpable processes > > Whether a process needs protection by IBPB on context switches is a > different question to whether a process should be allowed to be dumped, > though the former may be a superset of the latter. Enable IBPB on all > context switches to a different userspace process, until we have a clear > mitigation strategy for userspace against Spectre-v2 designed and > implemented. > > Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
-- Josh
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