| Message ID | 20190131085247.13826-13-mimu@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: s390: make use of the GIB | expand |
On Thu, 31 Jan 2019 09:52:43 +0100 Michael Mueller <mimu@linux.ibm.com> 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@linux.ibm.com> > --- > 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@linux.ibm.com> > > @@ -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); > } >
On 31/01/2019 09:52, Michael Mueller 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@linux.ibm.com> I would have written "will be removed by ...." however Reviewed-by: Pierre Morel<pmorel@linux.ibm.com>
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); } @@ -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); }
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@linux.ibm.com> --- arch/s390/kvm/interrupt.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-)