On Wed, May 03, 2017 at 06:06:31PM +0200, Andrew Jones wrote: > 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, > closing the race window and also allowing us to remove the final > check of power_off in VCPU RUN, as the final check for requests > is sufficient. > > Signed-off-by: Andrew Jones <[email protected]> > --- > arch/arm/kvm/arm.c | 3 +-- > arch/arm/kvm/psci.c | 5 ++--- > 2 files changed, 3 insertions(+), 5 deletions(-) > > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index 7be0d9b0c63a..26d9d4d72853 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -670,8 +670,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct > kvm_run *run) > smp_store_mb(vcpu->mode, IN_GUEST_MODE); > > if (ret <= 0 || need_new_vmid_gen(vcpu->kvm) || > - kvm_request_pending(vcpu) || > - vcpu->arch.power_off) { > + kvm_request_pending(vcpu)) { > vcpu->mode = OUTSIDE_GUEST_MODE; > local_irq_enable(); > kvm_pmu_sync_hwstate(vcpu); > diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c > index f68be2cc6256..f189d0ad30d5 100644 > --- a/arch/arm/kvm/psci.c > +++ b/arch/arm/kvm/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 >
Reviewed-by: Christoffer Dall <[email protected]> _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
