From b938eacea0b6881f2116a061e6da3ec840e75137 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 30 Apr 2015 13:33:59 +0200 Subject: [PATCH] KVM: s390: fix external call injection without sigp interpretation Commit ea5f49692575 ("KVM: s390: only one external call may be pending at a time") introduced a bug on machines that don't have SIGP interpretation facility installed. The injection of an external call will now always fail with -EBUSY (if none is already pending). This leads to the following symptoms: - An external call will be injected but with the wrong "src cpu id", as this id will not be remembered. - The target vcpu will not be woken up, therefore the guest will hang if it cannot deal with unexpected failures of the SIGP EXTERNAL CALL instruction. - If an external call is already pending, -EBUSY will not be reported. Reviewed-by: Christian Borntraeger Reviewed-by: Jens Freimann Signed-off-by: David Hildenbrand Cc: stable@vger.kernel.org # v4.0 Signed-off-by: Christian Borntraeger --- arch/s390/kvm/interrupt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 9de47265ef73..2836b25f63d3 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -1061,7 +1061,7 @@ static int __inject_extcall(struct kvm_vcpu *vcpu, struct kvm_s390_irq *irq) if (sclp_has_sigpif()) return __inject_extcall_sigpif(vcpu, src_id); - if (!test_and_set_bit(IRQ_PEND_EXT_EXTERNAL, &li->pending_irqs)) + if (test_and_set_bit(IRQ_PEND_EXT_EXTERNAL, &li->pending_irqs)) return -EBUSY; *extcall = irq->u.extcall; atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags); -- 2.20.1