Commit 3e005dc4 authored by Vladimir Murzin's avatar Vladimir Murzin Committed by Luis Henriques

arm: kvm: fix CPU hotplug

commit 37a34ac1 upstream.

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: default avatarVladimir Murzin <vladimir.murzin@arm.com>
Acked-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarShannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent 96c31a85
......@@ -826,7 +826,8 @@ 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;
}
......
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