This is a note to let you know that I've just added the patch titled KVM: s390: fix external call injection without sigp interpretation to the 4.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: kvm-s390-fix-external-call-injection-without-sigp-interpretation.patch and it can be found in the queue-4.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From b938eacea0b6881f2116a061e6da3ec840e75137 Mon Sep 17 00:00:00 2001 From: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx> Date: Thu, 30 Apr 2015 13:33:59 +0200 Subject: KVM: s390: fix external call injection without sigp interpretation From: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx> commit b938eacea0b6881f2116a061e6da3ec840e75137 upstream. 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 <borntraeger@xxxxxxxxxx> Reviewed-by: Jens Freimann <jfrei@xxxxxxxxxxxxxxxxxx> Signed-off-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/s390/kvm/interrupt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -1037,7 +1037,7 @@ static int __inject_extcall(struct kvm_v 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); Patches currently in stable-queue which might be from dahi@xxxxxxxxxxxxxxxxxx are queue-4.0/kvm-s390-fix-external-call-injection-without-sigp-interpretation.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html