System shutdown is currently using request-less VCPU kicks. This leaves open a tiny race window, as it doesn't ensure the state change to power_off is seen by a VCPU just about to enter guest mode. VCPU requests, OTOH, are guaranteed to be seen (see "Ensuring Requests Are Seen" of Documentation/virtual/kvm/vcpu-requests.rst) This patch applies the EXIT request used by pause to power_off, fixing the race.
Signed-off-by: Andrew Jones <[email protected]> --- virt/kvm/arm/psci.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c index f68be2cc6256..f189d0ad30d5 100644 --- a/virt/kvm/arm/psci.c +++ b/virt/kvm/arm/psci.c @@ -179,10 +179,9 @@ static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type) * after this call is handled and before the VCPUs have been * re-initialized. */ - kvm_for_each_vcpu(i, tmp, vcpu->kvm) { + kvm_for_each_vcpu(i, tmp, vcpu->kvm) tmp->arch.power_off = true; - kvm_vcpu_kick(tmp); - } + kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_VCPU_EXIT); memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event)); vcpu->run->system_event.type = type; -- 2.9.3 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
