Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <f86e2e05-114a-cc9e-8f3a-96b36889063d@linux.ibm.com>
Date:   Mon, 27 Jun 2022 16:57:42 -0400
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.9.1
Subject: Re: [PATCH v9 00/21] KVM: s390: enable zPCI for interpretive
 execution
Content-Language: en-US
From:   Matthew Rosato <mjrosato@linux.ibm.com>
To:     linux-s390@vger.kernel.org
Cc:     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,
        jgg@nvidia.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-doc@vger.kernel.org
References: <20220606203325.110625-1-mjrosato@linux.ibm.com>
In-Reply-To: <20220606203325.110625-1-mjrosato@linux.ibm.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 6/6/22 4:33 PM, Matthew Rosato wrote:
> Enable interpretive execution of zPCI instructions + adapter interruption
> forwarding for s390x KVM vfio-pci.  This is done by triggering a routine
> when the VFIO group is associated with the KVM guest, transmitting to
> firmware a special token (GISA designation) to enable that specific guest
> for interpretive execution on that zPCI device.  Load/store interpreation
> enablement is then controlled by userspace (based upon whether or not a
> SHM bit is placed in the virtual function handle).  Adapter Event
> Notification interpretation is controlled from userspace via a new KVM
> ioctl.
> 
> By allowing intepretation of zPCI instructions and firmware delivery of
> interrupts to guests, we can reduce the frequency of guest SIE exits for
> zPCI.
> 
>  From the perspective of guest configuration, you passthrough zPCI devices
> in the same manner as before, with intepretation support being used by
> default if available in kernel+qemu.
> 
> Will follow up with a link the most recent QEMU series.
> 
> Changelog v8->v9:
> - Rebase on top of 5.19-rc1, adjust ioctl and capability defines
> - s/kzdev = 0/kzdev = NULL/ (Alex)
> - rename vfio_pci_zdev_open to vfio_pci_zdev_open_device (Jason)
> - rename vfio_pci_zdev_release to vfio_pci_zdev_close_device (Jason)
> - make vfio_pci_zdev_close_device return void, instead WARN_ON or ignore
>    errors in lower level function (kvm_s390_pci_unregister_kvm) (Jason)
> - remove notifier accidentally left in struct zpci_dev + associated
>    include statment (Jason)
> - Remove patch 'KVM: s390: introduce CPU feature for zPCI Interpretation'
>    based on discussion in QEMU thread.
> 

Ping -- I'm hoping this can make the next merge window, but there are 
still 2 patches left without any review tag (16 & 17).