diff options
| -rw-r--r-- | arch/s390/kvm/interrupt.c | 74 |
1 files changed, 70 insertions, 4 deletions
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index dd4c50b..f2dc868 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -1471,20 +1471,86 @@ static struct kvm_s390_interrupt_info *get_io_int(struct kvm *kvm, return NULL; } +static struct kvm_s390_interrupt_info *get_top_io_int(struct kvm *kvm, + u64 isc_mask, u32 schid) +{ + struct kvm_s390_interrupt_info *inti = NULL; + int isc; + + for (isc = 0; isc <= MAX_ISC && !inti; isc++) { + if (isc_mask & isc_to_isc_bits(isc)) + inti = get_io_int(kvm, isc, schid); + } + return inti; +} + +static int get_top_gisa_isc(struct kvm *kvm, u64 isc_mask, u32 schid) +{ + unsigned long active_mask; + int isc; + + if (schid) + goto out; + if (!kvm->arch.gisa) + goto out; + + active_mask = (isc_mask & kvm_s390_gisa_get_ipm(kvm->arch.gisa) << 24) << 32; + while (active_mask) { + isc = __fls(active_mask) ^ (BITS_PER_LONG - 1); + if (kvm_s390_gisa_tac_ipm_gisc(kvm->arch.gisa, isc)) + return isc; + clear_bit_inv(isc, &active_mask); + } +out: + return -EINVAL; +} + /* * Dequeue and return an I/O interrupt matching any of the interruption * subclasses as designated by the isc mask in cr6 and the schid (if != 0). + * Take into account the interrupts pending in the interrupt list and in GISA. + * + * Note that for a guest that does not enable I/O interrupts + * but relies on TPI, a flood of classic interrupts may starve + * out adapter interrupts on the same isc. Linux does not do + * that, and it is possible to work around the issue by configuring + * different iscs for classic and adapter interrupts in the guest, + * but we may want to revisit this in the future. */ struct kvm_s390_interrupt_info *kvm_s390_get_io_int(struct kvm *kvm, u64 isc_mask, u32 schid) { - struct kvm_s390_interrupt_info *inti = NULL; + struct kvm_s390_interrupt_info *inti, *tmp_inti; int isc; - for (isc = 0; isc <= MAX_ISC && !inti; isc++) { - if (isc_mask & isc_to_isc_bits(isc)) - inti = get_io_int(kvm, isc, schid); + inti = get_top_io_int(kvm, isc_mask, schid); + + isc = get_top_gisa_isc(kvm, isc_mask, schid); + if (isc < 0) + /* no AI in GISA */ + goto out; + + if (!inti) + /* AI in GISA but no classical IO int */ + goto gisa_out; + + /* both types of interrupts present */ + if (int_word_to_isc(inti->io.io_int_word) <= isc) { + /* classical IO int with higher priority */ + kvm_s390_gisa_set_ipm_gisc(kvm->arch.gisa, isc); + goto out; } +gisa_out: + tmp_inti = kzalloc(sizeof(*inti), GFP_KERNEL); + if (tmp_inti) { + tmp_inti->type = KVM_S390_INT_IO(1, 0, 0, 0); + tmp_inti->io.io_int_word = isc_to_int_word(isc); + if (inti) + kvm_s390_reinject_io_int(kvm, inti); + inti = tmp_inti; + } else + kvm_s390_gisa_set_ipm_gisc(kvm->arch.gisa, isc); +out: return inti; } |
