| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 54/88] KVM: arm/arm64: Handle CPU_PM_ENTER_FAILED | Date | Thu, 15 Feb 2018 16:17:21 +0100 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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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>
--- arch/arm/kvm/arm.c | 1 + 1 file changed, 1 insertion(+)
--- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -1165,6 +1165,7 @@ 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. */
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