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arm: kvm: fix CPU hotplug

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On some platforms with no power management capabilities, the hotplug
implementation is allowed to return from a smp_ops.cpu_die() call as a
function return. Upon a CPU onlining event, the KVM CPU notifier tries
to reinstall the hyp stub, which fails on platform where no reset took
place following a hotplug event, with the message:

CPU1: smp_ops.cpu_die() returned, trying to resuscitate
CPU1: Booted secondary processor
Kernel panic - not syncing: unexpected prefetch abort in Hyp mode at: 0x80409540
unexpected data abort in Hyp mode at: 0x80401fe8
unexpected HVC/SVC trap in Hyp mode at: 0x805c6170

since KVM code is trying to reinstall the stub on a system where it is
already configured.

To prevent this issue, this patch adds a check in the KVM hotplug
notifier that detects if the HYP stub really needs re-installing when a
CPU is onlined and skips the installation call if the stub is already in
place, which means that the CPU has not been reset.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Vladimir Murzin 2014-09-22 15:52:48 +01:00 committed by Christoffer Dall
parent 0496daa5cf
commit 37a34ac1d4
1 changed files with 2 additions and 1 deletions
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3
arch/arm/kvm/arm.c
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@ -808,7 +808,8 @@ static int hyp_init_cpu_notify(struct notifier_block *self,
switch (action) {
case CPU_STARTING:
case CPU_STARTING_FROZEN:
cpu_init_hyp_mode(NULL);
if (__hyp_get_vectors() == hyp_default_vectors)
cpu_init_hyp_mode(NULL);
break;
}