On Tue, 25 Feb 2020 08:50:47 +0100 Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote: > This is the guest breaking event address. So a guest (and QEMU) can read it. > It is kind of overlaid sida and gbea. Something like this: > > diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c > index cd81a58349a9..055bf0ec8fbb 100644 > --- a/arch/s390/kvm/pv.c > +++ b/arch/s390/kvm/pv.c > @@ -39,6 +39,11 @@ int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc) > vcpu->arch.sie_block->pv_handle_config = 0; > memset(&vcpu->arch.pv, 0, sizeof(vcpu->arch.pv)); > vcpu->arch.sie_block->sdf = 0; > + /* > + * the sidad field (for sdf == 2) is now the gbea field (for sdf == 0). s/the sidad/The sidad/ > + * Use the reset value of gbea to not leak the kernel pointer of the s/to not leak/to avoid leaking/ > + * just free sida s/free sida/freed sida./ > + */ > vcpu->arch.sie_block->gbea = 1; > kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); >