Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
Message-ID: <b143e333-0add-8042-12de-7e9e8b275ec0@linux.ibm.com>
Date:   Tue, 12 Apr 2022 09:14:36 -0400
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.7.0
Subject: Re: [PATCH v5 15/21] KVM: s390: pci: add routines to start/stop
 interpretive execution
Content-Language: en-US
To:     Jason Gunthorpe <jgg@ziepe.ca>
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
References: <20220404174349.58530-1-mjrosato@linux.ibm.com>
 <20220404174349.58530-16-mjrosato@linux.ibm.com>
 <20220408124707.GY64706@ziepe.ca>
From:   Matthew Rosato <mjrosato@linux.ibm.com>
In-Reply-To: <20220408124707.GY64706@ziepe.ca>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 4/8/22 8:47 AM, Jason Gunthorpe wrote:
> On Mon, Apr 04, 2022 at 01:43:43PM -0400, Matthew Rosato wrote:
>> +int kvm_s390_pci_register_kvm(struct device *dev, void *data)
>> +{
>> +	struct zpci_dev *zdev = NULL;
>> +	struct kvm *kvm = data;
>> +
>> +	/* Only proceed for zPCI devices, quietly ignore others */
>> +	if (dev_is_pci(dev))
>> +		zdev = to_zpci_dev(dev);
>> +	if (!zdev)
>> +		return 0;
> 
> Especially since this only works if we have zpci device
> 
> So having the zpci code hook the kvm notifier and then call the arch
> code from the zpci area seems pretty OK
> 
> Also why is a struct kvm * being passed as a void *?

Only because the function is intended to be called via 
iommu_group_for_each_dev (next patch) which requires int (*fn)(struct 
device *, void *)