| Message ID | 20180214155636.60405-2-borntraeger@de.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index aabf46f5f883..337a69bc04db 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -1701,7 +1701,8 @@ static void __floating_irq_kick(struct kvm *kvm, u64 type) kvm_s390_set_cpuflags(dst_vcpu, CPUSTAT_STOP_INT); break; case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX: - kvm_s390_set_cpuflags(dst_vcpu, CPUSTAT_IO_INT); + if (!(type & KVM_S390_INT_IO_AI_MASK && kvm->arch.gisa)) + kvm_s390_set_cpuflags(dst_vcpu, CPUSTAT_IO_INT); break; default: kvm_s390_set_cpuflags(dst_vcpu, CPUSTAT_EXT_INT);
For interrupt injection of floating interrupts we queue the interrupt either in the GISA or in the floating interrupt list. The first CPU that looks at these data structures - either in KVM code or hardware will then deliver that interrupt. To minimize latency we also: -a: choose a VCPU to deliver that interrupt. We prefer idle CPUs -b: we wake up the host thread that runs the VCPU -c: set an I/O intervention bit for that CPU so that it exits guest context as soon as the PSW I/O mask is enabled This will make sure that this CPU will execute the interrupt delivery code of KVM very soon. We can now optimize the injection case if we have exitless interrupts. The wakeup is still necessary in case the target CPU sleeps. We can avoid the I/O intervention request bit though. Whenever this intervention request would be handled, the hardware could also directly inject the interrupt on that CPU, no need to go through the interrupt injection loop of KVM. Cc: Michael Mueller <mimu@linux.vnet.ibm.com> Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> --- arch/s390/kvm/interrupt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)