diff options
Diffstat (limited to 'arch/s390/kvm')
| -rw-r--r-- | arch/s390/kvm/interrupt.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 5efcd9e2cf8f..040745b23224 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -222,6 +222,33 @@ static inline u8 int_word_to_isc(u32 int_word) */ #define IPM_BIT_OFFSET (offsetof(struct kvm_s390_gisa, ipm) * BITS_PER_BYTE) +/** + * gisa_set_iam - change the GISA interruption alert mask + * + * @gisa: gisa to operate on + * @iam: new IAM value to use + * + * Change the IAM atomically with the next alert address and the IPM + * of the GISA if the GISA is not part of the GIB alert list. All three + * fields are located in the first long word of the GISA. + * + * Returns: 0 on success + * -EBUSY in case the gisa is part of the alert list + */ +static inline int gisa_set_iam(struct kvm_s390_gisa *gisa, u8 iam) +{ + u64 word, _word; + + do { + word = READ_ONCE(gisa->u64.word[0]); + if ((u64)gisa != word >> 32) + return -EBUSY; + _word = (word & ~0xffUL) | iam; + } while (cmpxchg(&gisa->u64.word[0], word, _word) != word); + + return 0; +} + static inline void gisa_set_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc) { set_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa); @@ -2911,6 +2938,8 @@ void kvm_s390_gisa_init(struct kvm *kvm) if (!css_general_characteristics.aiv) return; gi->origin = &kvm->arch.sie_page2->gisa; + gi->alert.mask = 0; + spin_lock_init(&gi->alert.ref_lock); kvm_s390_gisa_clear(kvm); VM_EVENT(kvm, 3, "gisa 0x%pK initialized", gi->origin); } @@ -2920,6 +2949,89 @@ void kvm_s390_gisa_destroy(struct kvm *kvm) kvm->arch.gisa_int.origin = NULL; } +/** + * kvm_s390_gisc_register - register a guest ISC + * + * @kvm: the kernel vm to work with + * @gisc: the guest interruption sub class to register + * + * The function extends the vm specific alert mask to use. + * The effective IAM mask in the GISA is updated as well + * in case the GISA is not part of the GIB alert list. + * It will be updated latest when the IAM gets restored + * by gisa_get_ipm_or_restore_iam(). + * + * Returns: the nonspecific ISC (NISC) the gib alert mechanism + * has registered with the channel subsystem. + * -ENODEV in case the vm uses no GISA + * -ERANGE in case the guest ISC is invalid + */ +int kvm_s390_gisc_register(struct kvm *kvm, u32 gisc) +{ + struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int; + + if (!gi->origin) + return -ENODEV; + if (gisc > MAX_ISC) + return -ERANGE; + + spin_lock(&gi->alert.ref_lock); + gi->alert.ref_count[gisc]++; + if (gi->alert.ref_count[gisc] == 1) { + gi->alert.mask |= 0x80 >> gisc; + gisa_set_iam(gi->origin, gi->alert.mask); + } + spin_unlock(&gi->alert.ref_lock); + + return gib->nisc; +} +EXPORT_SYMBOL_GPL(kvm_s390_gisc_register); + +/** + * kvm_s390_gisc_unregister - unregister a guest ISC + * + * @kvm: the kernel vm to work with + * @gisc: the guest interruption sub class to register + * + * The function reduces the vm specific alert mask to use. + * The effective IAM mask in the GISA is updated as well + * in case the GISA is not part of the GIB alert list. + * It will be updated latest when the IAM gets restored + * by gisa_get_ipm_or_restore_iam(). + * + * Returns: the nonspecific ISC (NISC) the gib alert mechanism + * has registered with the channel subsystem. + * -ENODEV in case the vm uses no GISA + * -ERANGE in case the guest ISC is invalid + * -EINVAL in case the guest ISC is not registered + */ +int kvm_s390_gisc_unregister(struct kvm *kvm, u32 gisc) +{ + struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int; + int rc = 0; + + if (!gi->origin) + return -ENODEV; + if (gisc > MAX_ISC) + return -ERANGE; + + spin_lock(&gi->alert.ref_lock); + if (gi->alert.ref_count[gisc] == 0) { + rc = -EINVAL; + goto out; + } + gi->alert.ref_count[gisc]--; + if (gi->alert.ref_count[gisc] == 0) { + gi->alert.mask &= ~(0x80 >> gisc); + gisa_set_iam(gi->origin, gi->alert.mask); + } +out: + spin_unlock(&gi->alert.ref_lock); + + return rc; +} +EXPORT_SYMBOL_GPL(kvm_s390_gisc_unregister); + void kvm_s390_gib_destroy(void) { if (!gib) |