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KVM: arm/arm64: Handle CPU_PM_ENTER_FAILED 

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: 67f6919766 ("arm64: kvm: allows kvm cpu hotplug")
Cc: <stable@vger.kernel.org> # v4.7+
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>
This commit is contained in:
James Morse 2018-01-22 18:19:06 +00:00 committed by Christoffer Dall
parent 0482b50546
commit 58d6b15e9d
1 changed files with 1 additions and 0 deletions
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1
virt/kvm/arm/arm.c
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@ -1262,6 +1262,7 @@ static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
cpu_hyp_reset(); cpu_hyp_reset();
return NOTIFY_OK; return NOTIFY_OK;
case CPU_PM_ENTER_FAILED:
case CPU_PM_EXIT: case CPU_PM_EXIT:
if (__this_cpu_read(kvm_arm_hardware_enabled)) if (__this_cpu_read(kvm_arm_hardware_enabled))
/* The hardware was enabled before suspend. */ /* The hardware was enabled before suspend. */