From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Borntraeger Subject: Re: [PATCH v11 26/26] s390: doc: detailed specifications for AP virtualization Date: Thu, 27 Sep 2018 13:59:23 +0200 Message-ID: References: <20180925231641.4954-1-akrowiak@linux.vnet.ibm.com> <20180925231641.4954-27-akrowiak@linux.vnet.ibm.com> <20180926164222.74731b74@t450s.home> <20180927135141.0fa87f2c.cohuck@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: Alex Williamson , Tony Krowiak , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, freude@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, kwankhede@nvidia.com, bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com, pmorel@linux.vnet.ibm.com, alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com, jjherne@linux.vnet.ibm.com, thuth@redhat.com, pasic@linux.vnet.ibm.com, berrange@redhat.com, fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com, frankja@linux.ibm.com, Tony Krowiak To: Cornelia Huck , Halil Pasic Return-path: In-Reply-To: <20180927135141.0fa87f2c.cohuck@redhat.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 09/27/2018 01:51 PM, Cornelia Huck wrote: > On Thu, 27 Sep 2018 13:29:43 +0200 > Halil Pasic wrote: > >> On 09/27/2018 12:42 AM, Alex Williamson wrote: >>> On Tue, 25 Sep 2018 19:16:41 -0400 >>> Tony Krowiak wrote: >>>> + This is how the matrix is configured for Guest2: >>>> + >>>> + echo 5 > assign_adapter >>>> + echo 0x47 > assign_domain >>>> + echo 0xff > assign_domain >>>> + >>>> + This is how the matrix is configured for Guest3: >>>> + >>>> + echo 6 > assign_adapter >>>> + echo 0x47 > assign_domain >>>> + echo 0xff > assign_domain >>>> + >>> >>> I'm curious why this interface didn't adopt the +/- notation invented >>> above for consistency. Too difficult to do rollbacks with a string on >>> entries? >>> >> >> I remember that we did discuss that possibility around v9, but I can't >> tell why did we decide to not implement it. Maybe Tony has an answer. > > IIRC, that was a discussion on the base ap driver interfaces rather > than vfio-ap. > >> >> Anyway, if we were to do that, we would use different attribute names >> (e.g. just domain_mask, or something similar instead of >> (assign|unassign)_xxx). So I think such an interface can still be added >> on top of the existing one. Having that said having multiple interfaces >> for the very same thing is usually not so nice IMHO. > > Nod to all of your points. > > As we do the configuration while the guest is not running anyway, the > different interfaces probably do not make that much difference in > practice. It should be fine to stick to the current interface for now > and only add a new one if we really think it is significantly better. Tony, can you maybe provide a quick on-top patch that clarifies Alex comments regarding the documentation? (State that is is big endian, fixup the small things etc). I can then either fold it in or provide it as an on top patch depending on how much has changed.