From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v5 1/7] s390: ap: kvm: add PQAP interception for AQIC Date: Fri, 15 Mar 2019 14:44:19 +0100 Message-ID: References: <1552493104-30510-1-git-send-email-pmorel@linux.ibm.com> <1552493104-30510-2-git-send-email-pmorel@linux.ibm.com> <20190315112032.13b259c2.cohuck@redhat.com> <20190315144141.100f2be7.cohuck@redhat.com> Reply-To: pmorel@linux.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190315144141.100f2be7.cohuck@redhat.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Cornelia Huck Cc: borntraeger@de.ibm.com, alex.williamson@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, frankja@linux.ibm.com, akrowiak@linux.ibm.com, pasic@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com, mimu@linux.ibm.com List-ID: On 15/03/2019 14:41, Cornelia Huck wrote: > On Fri, 15 Mar 2019 14:26:34 +0100 > Pierre Morel wrote: > >> Conclusion: we must handle this in userland, it will have the benefit >> to keep old behavior when there is no callback. >> OLD QEMU will not see change as they will not set aqic facility >> NEW QEMU will handle this correctly. >> >> In this case we also do not need to handle all other tests here but can >> move it to the callback as Tony wanted. >> >> Would you agree with something simple like: >> >> static int handle_pqap(struct kvm_vcpu *vcpu) >> { >> int ret = -EOPNOTSUPP; >> >> /* Verify that the hook callback is registered and call it */ >> if (pqap_hook) >> if (try_module_get(pqap_hook->owner)) { >> ret = pqap_hook->hook(vcpu); >> module_put(pqap_hook->owner); >> } >> return ret; >> } >> >> All other tests in QEMU and in the callback. > > With the hook checking for priv, fc, etc.? Yeah, might work. > > But don't count on my feedback too much right now, better wait for > others' comments :) I'll resume in April, if needed. > OK, thanks Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany