From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v9 12/22] s390: vfio-ap: sysfs interfaces to configure control domains Date: Wed, 22 Aug 2018 17:53:37 +0200 Message-ID: <7a03a9dd-2747-3a35-3048-a0b719edb955@linux.ibm.com> References: <1534196899-16987-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1534196899-16987-13-git-send-email-akrowiak@linux.vnet.ibm.com> <20180820162317.08bd7d23.cohuck@redhat.com> <660de00a-c403-28c1-4df4-82a973ab3ad5@linux.ibm.com> <20180821172548.57a6c758.cohuck@redhat.com> <82a391ee-85b1-cdc7-0f9b-d37fd8ba8e47@linux.ibm.com> <20180822114250.59a250aa.cohuck@redhat.com> <8bc5f207-f913-825c-f9fc-0a2c7fd280aa@linux.ibm.com> <219b352b-d5a2-189c-e205-82e7f9ae3d64@de.ibm.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: <219b352b-d5a2-189c-e205-82e7f9ae3d64@de.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Christian Borntraeger , Cornelia Huck , Halil Pasic Cc: Tony Krowiak , 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, alex.williamson@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 List-ID: On 22/08/2018 17:48, Christian Borntraeger wrote: > On 08/22/2018 05:34 PM, Pierre Morel wrote: >> On 22/08/2018 17:11, Christian Borntraeger wrote: >>> >>> >>> On 08/22/2018 01:03 PM, Pierre Morel wrote: >>>>> That's interesting. >>>>> >>>>>> IMHO this quote is quite a half-full half-empty cup one: >>>>>> * it mandates the set of usage domains is a subset of the set >>>>>> of the control domains, but >>>>>> * it speaks of independent controls, namely about the 'usage domain index' >>>>>> and the 'control domain index list' and makes the enforcement of the rule >>>>>> a job of the administrator (instead of codifying it in the controls). >>>>> I'm wondering if a configuration with a usage domain that is not also a >>>>> control domain is rejected outright? Anybody tried that? :) >>>> >>>> Yes, and no it is not. >>>> We can use a queue (usage domain) to a AP card for SHA-512 or RSA without >>>> having to define the queue as a control domain. >>> >>> Huh? My HMC allows to add a domain as >>> - control only domain >>> - control and usage domain. >>> >>> But I am not able to configure a usage-only domain for my LPAR. That seems to match >>> the current code, no? >>> >> >> Yes, it may not be configurable by the HMC but if we start a guest with no control domain it is not a problem to access the hardware through the usage domain. >> >> I tested this a long time ago, but tested again today to be sure on my LPAR. >> >> AFAIU adding a control only domain and a control and usage domain >> allows say: >> control and usage domain 1 >> control only domain 2 >> >> Allow to send a message to domain 2 using queue 1 >> >> Allow also to send a domain modifying message to domain 1 using queue 1 >> >> control domain are domain which are controlled > > So you have changed the code to not automatically make a usage domain a > control domain in the bitfield (and you could still use it as a usage > domain). Correct? yes and I used Harald's libica tests to verify it in the guest. > I think this is probably expected. the "usage implies control" seems to > be a convention implemented by HMC (lpar) and z/VM but millicode offers > the bits to have usage-only domains. As LPAR and z/VM will always enable > any usage-domain to also be a control domain we should do the same. > > >> It seems that the HMC enforce the LPARs to have access to their usage domain (AFAIU from Harald) -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany