From: Christian Borntraeger <borntraeger@linux.ibm.com>
To: Jason Gunthorpe <jgg@nvidia.com>,
Matthew Rosato <mjrosato@linux.ibm.com>
Cc: linux-s390@vger.kernel.org, alex.williamson@redhat.com,
cohuck@redhat.com, schnelle@linux.ibm.com, farman@linux.ibm.com,
pmorel@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com,
gerald.schaefer@linux.ibm.com, agordeev@linux.ibm.com,
svens@linux.ibm.com, frankja@linux.ibm.com, david@redhat.com,
imbrenda@linux.ibm.com, vneethv@linux.ibm.com,
oberpar@linux.ibm.com, freude@linux.ibm.com, thuth@redhat.com,
pasic@linux.ibm.com, pbonzini@redhat.com, corbet@lwn.net,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org
Subject: Re: [PATCH v6 16/21] vfio-pci/zdev: add open/close device hooks
Date: Fri, 6 May 2022 17:56:25 +0200 [thread overview]
Message-ID: <8c48614a-4e93-a575-1a08-ead955ad2a91@linux.ibm.com> (raw)
In-Reply-To: <20220427153924.GZ2125828@nvidia.com>
Am 27.04.22 um 17:39 schrieb Jason Gunthorpe:
> On Wed, Apr 27, 2022 at 11:26:40AM -0400, Matthew Rosato wrote:
>>>> zPCI devices (zpci_dev) exist regardless of whether kvm is configured or
>>>> not, and you can e.g. bind the associated PCI device to vfio-pci when KVM is
>>>> not configured (or module not loaded) and get the existing vfio-pci-zdev
>>>> extensions for that device (extra VFIO_DEVICE_INFO response data). Making a
>>>> direct dependency on KVM would remove that; this was discussed in a prior
>>>> version because this extra info is not used today outside of a KVM usecase
>>>> are not specific to kvm that need vfio-pci-zdev).
>>>
>>> I'm a bit confused, what is the drawback of just having a direct
>>> symbol dependency here? It means vfio loads a little extra kernel
>>> module code, but is that really a big worry given almost all vfio
>>> users on s390 will be using it with kvm?
>>
>> It's about trying to avoid loading unnecessary code (or at least giving a
>> way to turn it off).
>>
>> Previously I did something like....
>>
>> https://lore.kernel.org/kvm/20220204211536.321475-15-mjrosato@linux.ibm.com/
>>
>> And could do so again; as discussed in the thread there, I can use e.g.
>> CONFIG_VFIO_PCI_ZDEV_KVM and make vfio-pci-zdev depend on KVM in this
>> series. You only get the vfio-pci-zdev extensions when you configure KVM.
>
> That make sense to me, I'd rather see that then the symbol_get/put here
I agree with Jason here.
next prev parent reply other threads:[~2022-05-06 15:56 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-26 20:08 [PATCH v6 00/21] KVM: s390: enable zPCI for interpretive execution Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 01/21] s390/sclp: detect the zPCI load/store interpretation facility Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 02/21] s390/sclp: detect the AISII facility Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 03/21] s390/sclp: detect the AENI facility Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 04/21] s390/sclp: detect the AISI facility Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 05/21] s390/airq: pass more TPI info to airq handlers Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 06/21] s390/airq: allow for airq structure that uses an input vector Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 07/21] s390/pci: externalize the SIC operation controls and routine Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 08/21] s390/pci: stash associated GISA designation Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 09/21] s390/pci: stash dtsm and maxstbl Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 10/21] KVM: s390: pci: add basic kvm_zdev structure Matthew Rosato
2022-04-27 8:41 ` kernel test robot
2022-04-27 13:25 ` Matthew Rosato
2022-04-27 13:25 ` Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 11/21] KVM: s390: pci: do initial setup for AEN interpretation Matthew Rosato
2022-05-05 10:16 ` Christian Borntraeger
2022-04-26 20:08 ` [PATCH v6 12/21] KVM: s390: pci: enable host forwarding of Adapter Event Notifications Matthew Rosato
2022-05-05 12:37 ` Christian Borntraeger
2022-04-26 20:08 ` [PATCH v6 13/21] KVM: s390: mechanism to enable guest zPCI Interpretation Matthew Rosato
2022-05-05 13:10 ` Christian Borntraeger
2022-04-26 20:08 ` [PATCH v6 14/21] KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding Matthew Rosato
2022-05-06 15:35 ` Christian Borntraeger
2022-05-06 15:55 ` Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 15/21] KVM: s390: pci: add routines to start/stop interpretive execution Matthew Rosato
2022-04-27 15:14 ` Jason Gunthorpe
2022-04-27 20:20 ` Matthew Rosato
2022-04-28 12:28 ` Jason Gunthorpe
2022-04-26 20:08 ` [PATCH v6 16/21] vfio-pci/zdev: add open/close device hooks Matthew Rosato
2022-04-27 14:04 ` Jason Gunthorpe
2022-04-27 14:42 ` Matthew Rosato
2022-04-27 15:01 ` Jason Gunthorpe
2022-04-27 15:26 ` Matthew Rosato
2022-04-27 15:39 ` Jason Gunthorpe
2022-05-06 15:56 ` Christian Borntraeger [this message]
2022-04-26 20:08 ` [PATCH v6 17/21] vfio-pci/zdev: add function handle to clp base capability Matthew Rosato
2022-05-06 16:02 ` Christian Borntraeger
2022-04-26 20:08 ` [PATCH v6 18/21] vfio-pci/zdev: different maxstbl for interpreted devices Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 19/21] KVM: s390: add KVM_S390_ZPCI_OP to manage guest zPCI devices Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 20/21] KVM: s390: introduce CPU feature for zPCI Interpretation Matthew Rosato
2022-04-26 20:08 ` [PATCH v6 21/21] MAINTAINERS: additional files related kvm s390 pci passthrough Matthew Rosato
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