This is a note to let you know that I've just added the patch titled

KVM: arm/arm64: Handle CPU_PM_ENTER_FAILED

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: kvm-arm-arm64-handle-cpu_pm_enter_failed.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 58d6b15e9da5042a99c9c30ad725792e4569150e Mon Sep 17 00:00:00 2001

From: James Morse james.morse@arm.com Date: Mon, 22 Jan 2018 18:19:06 +0000 Subject: KVM: arm/arm64: Handle CPU_PM_ENTER_FAILED

From: James Morse james.morse@arm.com

commit 58d6b15e9da5042a99c9c30ad725792e4569150e upstream.

cpu_pm_enter() calls the pm notifier chain with CPU_PM_ENTER, then if there is a failure: CPU_PM_ENTER_FAILED.

When KVM receives CPU_PM_ENTER it calls cpu_hyp_reset() which will return us to the hyp-stub. If we subsequently get a CPU_PM_ENTER_FAILED, KVM does nothing, leaving the CPU running with the hyp-stub, at odds with kvm_arm_hardware_enabled.

Add CPU_PM_ENTER_FAILED as a fallthrough for CPU_PM_EXIT, this reloads KVM based on kvm_arm_hardware_enabled. This is safe even if CPU_PM_ENTER never gets as far as KVM, as cpu_hyp_reinit() calls cpu_hyp_reset() to make sure the hyp-stub is loaded before reloading KVM.

Fixes: 67f691976662 ("arm64: kvm: allows kvm cpu hotplug") CC: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Reviewed-by: Christoffer Dall christoffer.dall@linaro.org Signed-off-by: James Morse james.morse@arm.com Signed-off-by: Christoffer Dall christoffer.dall@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- virt/kvm/arm/arm.c | 1 + 1 file changed, 1 insertion(+)

--- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -1220,6 +1220,7 @@ static int hyp_init_cpu_pm_notifier(stru cpu_hyp_reset();

return NOTIFY_OK; + case CPU_PM_ENTER_FAILED: case CPU_PM_EXIT: if (__this_cpu_read(kvm_arm_hardware_enabled)) /* The hardware was enabled before suspend. */

Patches currently in stable-queue which might be from james.morse@arm.com are

queue-4.14/arm64-kpti-fix-the-interaction-between-asid-switching-and-software-pan.patch queue-4.14/arm64-move-task_-definitions-to-asm-processor.h.patch queue-4.14/kvm-arm-arm64-handle-cpu_pm_enter_failed.patch queue-4.14/arm64-cpufeature-__this_cpu_has_cap-shouldn-t-stop-early.patch