Messages in this thread | | | Subject | Re: [PATCH v5 10/15] KVM: s390: add functions to (un)register GISC with GISA | From | Pierre Morel <> | Date | Wed, 2 Jan 2019 18:29:00 +0100 |
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On 19/12/2018 20:17, Michael Mueller wrote: > Add the IAM (Interruption Alert Mask) to the architecture specific > kvm struct. This mask in the GISA is used to define for which ISC > a GIB alert can be issued. > > The functions kvm_s390_gisc_register() and kvm_s390_gisc_unregister() > are used to (un)register a GISC (guest ISC) with a virtual machine and > its GISA. > > Upon successful completion, kvm_s390_gisc_register() returns the > ISC to be used for GIB alert interruptions. A negative return code > indicates an error during registration. > > Theses functions will be used by other adapter types like AP and PCI to > request pass-through interruption support. > > Signed-off-by: Michael Mueller <mimu@linux.ibm.com> > --- > arch/s390/include/asm/kvm_host.h | 9 ++++++ > arch/s390/kvm/interrupt.c | 66 ++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 75 insertions(+) > > diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h > index 0deba3ae8bc7..2c1259da3636 100644 > --- a/arch/s390/include/asm/kvm_host.h > +++ b/arch/s390/include/asm/kvm_host.h > @@ -782,6 +782,9 @@ struct kvm_s390_gisa { > u8 reserved03[11]; > u32 airq_count; > } g1; > + struct { > + u64 word[4]; > + } u64; > }; > }; > > @@ -849,6 +852,9 @@ struct kvm_arch{ > DECLARE_BITMAP(cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS); > struct kvm_s390_gisa *gisa; > int gib_in_use; > + u8 iam; > + u32 iam_ref_count[MAX_ISC + 1]; > + spinlock_t iam_ref_lock; > }; > > #define KVM_HVA_ERR_BAD (-1UL) > @@ -882,6 +888,9 @@ void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm, > extern int sie64a(struct kvm_s390_sie_block *, u64 *); > extern char sie_exit; > > +extern int kvm_s390_gisc_register(struct kvm *kvm, u32 gisc); > +extern int kvm_s390_gisc_unregister(struct kvm *kvm, u32 gisc); > + > static inline void kvm_arch_hardware_disable(void) {} > static inline void kvm_arch_check_processor_compat(void *rtn) {} > static inline void kvm_arch_sync_events(struct kvm *kvm) {} > diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c > index 5a54360cecfe..1cc3ad2e6c7e 100644 > --- a/arch/s390/kvm/interrupt.c > +++ b/arch/s390/kvm/interrupt.c > @@ -229,6 +229,25 @@ static inline u8 int_word_to_isc(u32 int_word) > */ > #define IPM_BIT_OFFSET (offsetof(struct kvm_s390_gisa, ipm) * BITS_PER_BYTE) > > +static inline int set_iam(struct kvm_s390_gisa *gisa, u8 iam) > +{ > + u64 word0, _word0; > + > + do { > + word0 = READ_ONCE(gisa->u64.word[0]); > + /* If the GISA is in the alert list, do nothing. */ > + if ((u64)gisa != word0 >> 32) > + return -EBUSY;
In kvm_s390_gisa_clear() you do:
+ nullify_gisa(kvm->arch.gisa); + set_iam(kvm->arch.gisa, kvm->arch.iam);
IIUC this call to set_iam() will always fail.
> + /* > + * Try to set the IAM or loop, if the IPM has changed > + * or the GISA has been inserted into the alert list. > + */ > + _word0 = (word0 & ~0xffUL) | iam; > + } while (cmpxchg(&gisa->u64.word[0], word0, _word0) != _word0); > + > + return 0; > +} > + > static inline void set_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc) > { > set_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa); > @@ -2917,6 +2936,8 @@ void kvm_s390_gisa_init(struct kvm *kvm) > if (!css_general_characteristics.aiv) > return; > kvm->arch.gisa = &kvm->arch.sie_page2->gisa; > + kvm->arch.iam = 0; > + spin_lock_init(&kvm->arch.iam_ref_lock); > nullify_gisa(kvm->arch.gisa); > kvm->arch.gib_in_use = !!gib; > VM_EVENT(kvm, 3, "gisa 0x%pK initialized", kvm->arch.gisa); > @@ -2929,6 +2950,51 @@ void kvm_s390_gisa_destroy(struct kvm *kvm) > kvm->arch.gisa = NULL; > } > > +int kvm_s390_gisc_register(struct kvm *kvm, u32 gisc) > +{ > + if (!kvm->arch.gib_in_use) > + return -ENODEV; > + if (gisc > MAX_ISC) > + return -ERANGE; > + > + spin_lock(&kvm->arch.iam_ref_lock); > + if (kvm->arch.iam_ref_count[gisc] == 0) > + kvm->arch.iam |= 0x80 >> gisc; > + kvm->arch.iam_ref_count[gisc]++; > + if (kvm->arch.iam_ref_count[gisc] == 1) > + set_iam(kvm->arch.gisa, kvm->arch.iam);
testing the set_iam return value? Even it should be fine if the caller works correctly, this is done before GISA is ever used.
> + spin_unlock(&kvm->arch.iam_ref_lock); > + > + return gib->nisc; > +} > +EXPORT_SYMBOL_GPL(kvm_s390_gisc_register); > + > +int kvm_s390_gisc_unregister(struct kvm *kvm, u32 gisc) > +{ > + int rc = 0; > + > + if (!kvm->arch.gib_in_use) > + return -ENODEV; > + if (gisc > MAX_ISC) > + return -ERANGE; > + > + spin_lock(&kvm->arch.iam_ref_lock); > + if (kvm->arch.iam_ref_count[gisc] == 0) { > + rc = -EINVAL; > + goto out; > + } > + kvm->arch.iam_ref_count[gisc]--; > + if (kvm->arch.iam_ref_count[gisc] == 0) { > + kvm->arch.iam &= ~(0x80 >> gisc); > + set_iam(kvm->arch.gisa, kvm->arch.iam); > + } > +out: > + spin_unlock(&kvm->arch.iam_ref_lock); > + > + return rc; > +} > +EXPORT_SYMBOL_GPL(kvm_s390_gisc_unregister); > + > void kvm_s390_gib_destroy(void) > { > if (!gib) >
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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