From: Matthew Rosato <mjrosato@linux.ibm.com>
To: Jason Gunthorpe <jgg@nvidia.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, borntraeger@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: Wed, 27 Apr 2022 10:42:07 -0400 [thread overview]
Message-ID: <f6c78792-9cf7-0cde-f760-76166f9b7eb7@linux.ibm.com> (raw)
In-Reply-To: <20220427140410.GX2125828@nvidia.com>
On 4/27/22 10:04 AM, Jason Gunthorpe wrote:
> On Tue, Apr 26, 2022 at 04:08:37PM -0400, Matthew Rosato wrote:
>
>> +static int vfio_pci_zdev_group_notifier(struct notifier_block *nb,
>> + unsigned long action, void *data)
>> +{
>> + struct zpci_dev *zdev = container_of(nb, struct zpci_dev, nb);
>> + int (*fn)(struct zpci_dev *zdev, struct kvm *kvm);
>> + int rc = NOTIFY_OK;
>> +
>> + if (action == VFIO_GROUP_NOTIFY_SET_KVM) {
>> + if (!zdev)
>> + return NOTIFY_DONE;
>> +
>> + fn = symbol_get(kvm_s390_pci_register_kvm);
>> + if (!fn)
>> + return NOTIFY_DONE;
>> +
>> + if (fn(zdev, (struct kvm *)data))
>> + rc = NOTIFY_BAD;
>> +
>> + symbol_put(kvm_s390_pci_register_kvm);
>
> Is it possible this function can be in statically linked arch code?
>
> Or, actually, is zPCI useful anyhow without kvm ie can you just have a
> direct dependency here?
>
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 -- but it could be useful in the
future (or we may have other s390-isms that are not specific to kvm that
need vfio-pci-zdev).
As far as statically linking in arch... The fundamental
(un)registration task being done here -- (dis)associating the guest GISA
with the firmware and thus allowing this particular guest to use
firmware assists (or turning it off when kvm == 0) -- is only relevant
to guest passthrough with kvm and calls a number of different routines
that reside in the kvm module during the (un)registration process.
Without a direct dependency I think a symbol lookup still has to
inevitably happen at some point in the call chain.
next prev parent reply other threads:[~2022-04-27 14:42 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 [this message]
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
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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