diff options
Diffstat (limited to 'arch/s390/kvm')
| -rw-r--r-- | arch/s390/kvm/interrupt.c | 7 | ||||
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 9 | ||||
| -rw-r--r-- | arch/s390/kvm/kvm-s390.h | 1 | ||||
| -rw-r--r-- | arch/s390/kvm/sigp.c | 28 |
4 files changed, 43 insertions, 2 deletions
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 2245f4b8d362..8ce03a5ca863 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -2115,6 +2115,13 @@ int kvm_s390_is_stop_irq_pending(struct kvm_vcpu *vcpu) return test_bit(IRQ_PEND_SIGP_STOP, &li->pending_irqs); } +int kvm_s390_is_restart_irq_pending(struct kvm_vcpu *vcpu) +{ + struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int; + + return test_bit(IRQ_PEND_RESTART, &li->pending_irqs); +} + void kvm_s390_clear_stop_irq(struct kvm_vcpu *vcpu) { struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int; diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 1c97493d21e1..24e42bd7d3b7 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -4642,10 +4642,15 @@ int kvm_s390_vcpu_stop(struct kvm_vcpu *vcpu) } } - /* SIGP STOP and SIGP STOP AND STORE STATUS has been fully processed */ + /* + * Set the VCPU to STOPPED and THEN clear the interrupt flag, + * now that the SIGP STOP and SIGP STOP AND STORE STATUS orders + * have been fully processed. This will ensure that the VCPU + * is kept BUSY if another VCPU is inquiring with SIGP SENSE. + */ + kvm_s390_set_cpuflags(vcpu, CPUSTAT_STOPPED); kvm_s390_clear_stop_irq(vcpu); - kvm_s390_set_cpuflags(vcpu, CPUSTAT_STOPPED); __disable_ibs_on_vcpu(vcpu); for (i = 0; i < online_vcpus; i++) { diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h index 52bc8fbaa60a..1539dd981104 100644 --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -418,6 +418,7 @@ void kvm_s390_destroy_adapters(struct kvm *kvm); int kvm_s390_ext_call_pending(struct kvm_vcpu *vcpu); extern struct kvm_device_ops kvm_flic_ops; int kvm_s390_is_stop_irq_pending(struct kvm_vcpu *vcpu); +int kvm_s390_is_restart_irq_pending(struct kvm_vcpu *vcpu); void kvm_s390_clear_stop_irq(struct kvm_vcpu *vcpu); int kvm_s390_set_irq_state(struct kvm_vcpu *vcpu, void __user *buf, int len); diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c index 683036c1c92a..3dc921e853b6 100644 --- a/arch/s390/kvm/sigp.c +++ b/arch/s390/kvm/sigp.c @@ -288,6 +288,34 @@ static int handle_sigp_dst(struct kvm_vcpu *vcpu, u8 order_code, if (!dst_vcpu) return SIGP_CC_NOT_OPERATIONAL; + /* + * SIGP RESTART, SIGP STOP, and SIGP STOP AND STORE STATUS orders + * are processed asynchronously. Until the affected VCPU finishes + * its work and calls back into KVM to clear the (RESTART or STOP) + * interrupt, we need to return any new non-reset orders "busy". + * + * This is important because a single VCPU could issue: + * 1) SIGP STOP $DESTINATION + * 2) SIGP SENSE $DESTINATION + * + * If the SIGP SENSE would not be rejected as "busy", it could + * return an incorrect answer as to whether the VCPU is STOPPED + * or OPERATING. + */ + if (order_code != SIGP_INITIAL_CPU_RESET && + order_code != SIGP_CPU_RESET) { + /* + * Lockless check. Both SIGP STOP and SIGP (RE)START + * properly synchronize everything while processing + * their orders, while the guest cannot observe a + * difference when issuing other orders from two + * different VCPUs. + */ + if (kvm_s390_is_stop_irq_pending(dst_vcpu) || + kvm_s390_is_restart_irq_pending(dst_vcpu)) + return SIGP_CC_BUSY; + } + switch (order_code) { case SIGP_SENSE: vcpu->stat.instruction_sigp_sense++; |