From: Christian Borntraeger <borntraeger@xxxxxxxxxx> 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 2955c83f72801245afd0fe5c560cc75b82bea9aa upstream. Since commit 7c470539c95630c1f2a10f109e96f249730b75eb (s390/kvm: avoid automatic sie reentry) we will run through the C code of KVM on host interrupts instead of just reentering the guest. This will result in additional ucontrol exits (at least HZ per second). Let handle a 0 intercept in the kernel and dont return to userspace, even if in ucontrol mode. Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> Reviewed-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- arch/s390/kvm/kvm-s390.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 776dafe918db..48bb1c129963 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -788,7 +788,8 @@ rerun_vcpu: if (rc) break; if (kvm_is_ucontrol(vcpu->kvm)) - rc = -EOPNOTSUPP; + /* Don't exit for host interrupts. */ + rc = vcpu->arch.sie_block->icptcode ? -EOPNOTSUPP : 0; else rc = kvm_handle_sie_intercept(vcpu); } while (!signal_pending(current) && !rc); -- 1.9.3 -- 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