Am 20.10.21 um 09:52 schrieb Halil Pasic:
On Tue, 19 Oct 2021 23:35:25 +0200 Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:@@ -426,6 +426,7 @@ static void __unset_cpu_idle(struct kvm_vcpu *vcpu) { kvm_s390_clear_cpuflags(vcpu, CPUSTAT_WAIT); clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.idle_mask); + clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.gisa_int.kicked_mask);BTW, do you know are bit-ops garanteed to be serialized as seen by another cpu even when acting on a different byte? I mean could the kick_single_vcpu() set the clear of the kicked_mask bit but not see the clear of the idle mask?
clear_bit explicitely says. * This is a relaxed atomic operation (no implied memory barriers). so if we really need the ordering, then we need to add a barrier.
If that is not true we may need some barriers, or possibly merging the two bitmasks like idle bit, kick bit alterating to ensure there absolutely ain't no race.
