On Thu, 31 Jan 2019 09:52:43 +0100 Michael Mueller <mimu@xxxxxxxxxxxxx> wrote: > Function kvm_s390_gisa_clear() now clears the Interruption > Pending Mask of the GISA asap. If the GISA is in the alert > list at this time it stays in the list but is removed by > process_gib_alert_list(). > > Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxx> > --- > arch/s390/kvm/interrupt.c | 25 ++++++++++++++++++++++--- > 1 file changed, 22 insertions(+), 3 deletions(-) > > diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c > index f37dfb01c63c..341664b94491 100644 > --- a/arch/s390/kvm/interrupt.c > +++ b/arch/s390/kvm/interrupt.c > @@ -249,6 +249,25 @@ static inline int gisa_set_iam(struct kvm_s390_gisa *gisa, u8 iam) > return 0; > } > > +/** > + * gisa_clear_ipm - clear the GISA interruption pending mask > + * > + * @gisa: gisa to operate on > + * > + * Clear the IPM atomically with the next alert address and the IAM > + * of the GISA unconditionally. All three fields are located in the > + * first long word of the GISA. > + */ > +static inline void gisa_clear_ipm(struct kvm_s390_gisa *gisa) > +{ > + u64 word, _word; > + > + do { > + word = READ_ONCE(gisa->u64.word[0]); > + _word = word & ~(0xffUL << 24); > + } while (cmpxchg(&gisa->u64.word[0], word, _word) != word); > +} > + > static inline void gisa_set_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc) > { > set_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa); > @@ -2926,8 +2945,7 @@ void kvm_s390_gisa_clear(struct kvm *kvm) > > if (!gi->origin) > return; > - memset(gi->origin, 0, sizeof(struct kvm_s390_gisa)); > - gi->origin->next_alert = (u32)(u64)gi->origin; > + gisa_clear_ipm(gi->origin); > VM_EVENT(kvm, 3, "gisa 0x%pK cleared", gi->origin); > } I'm a bit confused. Now all kvm_s390_gisa_clear() does to the gisa is gisa_clear_ipm(). The only usage I see is triggered by KVM_DEV_FLIC_CLEAR_IRQS. And in that context this seems appropriate. However gisa can hold other stuff than the ipm, and in that sense the name kvm_s390_gisa_clear() may be misleading. I ask myself questions like who would need to reset simm and nimm on system reset. At the moment we don't use these AFAICT, so I guess it does not matter. Thus not a showstopper to me: Acked-by: Halil Pasic <pasic@xxxxxxxxxxxxx> > > @@ -2940,7 +2958,8 @@ void kvm_s390_gisa_init(struct kvm *kvm) > gi->origin = &kvm->arch.sie_page2->gisa; > gi->alert.mask = 0; > spin_lock_init(&gi->alert.ref_lock); > - kvm_s390_gisa_clear(kvm); > + memset(gi->origin, 0, sizeof(struct kvm_s390_gisa)); > + gi->origin->next_alert = (u32)(u64)gi->origin; > VM_EVENT(kvm, 3, "gisa 0x%pK initialized", gi->origin); > } >