arm64: Select POSIX_CPU_TIMERS_TASK_WORK

With 6caa5812e2 ("KVM: arm64: Use generic KVM xfer to guest work
function") all arm64 exit paths are properly equipped to handle the
POSIX timers' task work.

Deferring timer callbacks to thread context, not only limits the amount
of time spent in hard interrupt context, but is a safer
implementation[1], and will allow PREEMPT_RT setups to use KVM[2].

So let's enable POSIX_CPU_TIMERS_TASK_WORK on arm64.

[1] https://lore.kernel.org/all/20200716201923.228696399@linutronix.de/
[2] https://lore.kernel.org/linux-rt-users/87v92bdnlx.ffs@tglx/

Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211018144713.873464-1-nsaenzju@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Nicolas Saenz Julienne 2021-10-18 16:47:13 +02:00 • committed by Will Deacon
commit a68773bd32