From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Mon, 29 Sep 2014 16:03:09 +0200 Subject: [PATCH] arm: kvm: fix CPU hotplug In-Reply-To: <1411397568-4738-1-git-send-email-vladimir.murzin@arm.com> References: <1411397568-4738-1-git-send-email-vladimir.murzin@arm.com> Message-ID: <20140929140309.GJ3095@cbox> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Sep 22, 2014 at 03:52:48PM +0100, Vladimir Murzin wrote: > 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 Applied to queue, thanks -Christoffer