On Thu, Nov 21, 2024 at 12:07:19PM -0800, Josh Poimboeuf wrote: > User->user Spectre v2 attacks (including RSB) across context switches > are already mitigated by IBPB in cond_mitigation(), if enabled globally > or if either the prev or the next task has opted in to protection. RSB > filling without IBPB serves no purpose for protecting user space, as > indirect branches are still vulnerable. Question for Intel/AMD folks: where is it documented that IBPB clears the RSB? I thought I'd seen this somewhere but I can't seem to find it. -- Josh
