From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Sat, 18 Oct 2014 12:56:51 +0100 Subject: [PATCH 01/12] arm: kvm: fix CPU hotplug In-Reply-To: <1413633422-14907-1-git-send-email-marc.zyngier@arm.com> References: <1413633422-14907-1-git-send-email-marc.zyngier@arm.com> Message-ID: <1413633422-14907-2-git-send-email-marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Vladimir Murzin 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 Acked-by: Lorenzo Pieralisi Acked-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm/kvm/arm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 7796051..45e5f67 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -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; } -- 2.1.1