Lines Matching +full:d +full:- +full:cache +full:- +full:sets

1 .. SPDX-License-Identifier: GPL-2.0
15 ----------------
16 A cross-HT attack involves the attacker and victim running on different Hyper
18 full mitigation of cross-HT attacks is to disable Hyper Threading (HT). Core
19 scheduling is a scheduler feature that can mitigate some (not all) cross-HT
21 user-designated trusted group can share a core. This increase in core sharing
27 core involves additional overhead - especially when the system is lightly
29 scheduling to perform more poorly compared to SMT-disabled, where N_CPUS is the
33 -----
35 Using this feature, userspace defines groups of tasks that can be co-scheduled
55     - ``PR_SCHED_CORE_GET`` -- get core_sched cookie of ``pid``.
56     - ``PR_SCHED_CORE_CREATE`` -- create a new unique cookie for ``pid``.
57     - ``PR_SCHED_CORE_SHARE_TO`` -- push core_sched cookie to ``pid``.
58     - ``PR_SCHED_CORE_SHARE_FROM`` -- pull core_sched cookie from ``pid``.
65     ``PR_SCHED_CORE_SCOPE_``-prefixed macro constants.  For example, if arg4
80 cookie and thus a core is to rely on the fact that the core-sched cookie is
83 same core-sched group.
94 ---------------------
119 Forced-idling of hyperthreads
130 When the highest priority task is selected to run, a reschedule-IPI is sent to
136    A      idle -> user space      user space -> idle
137    B      idle -> user space      guest -> idle
138    C      idle -> guest           user space -> idle
139    D      idle -> guest           guest -> idle
157 and are considered system-wide trusted. The forced-idling of siblings running
158 cookie-0 tasks is also avoided.
160 Once userspace uses the above mentioned interfaces to group sets of tasks, tasks
164 Limitations of core-scheduling
165 ------------------------------
177 IPI. Even though cache is flushed on entry to user mode, victim tasks on siblings
178 may populate data in the cache and micro architectural buffers after the attacker
181 Open cross-HT issues that core scheduling does not solve
182 --------------------------------------------------------
218 ---------------
219 The main use case for Core scheduling is mitigating the cross-HT vulnerabilities
222 - Isolating tasks that needs a whole core: Examples include realtime tasks, tasks
224 - Gang scheduling: Requirements for a group of tasks that needs to be scheduled