From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH v9 0/4] vfio: ap: AP Queue Interrupt Control References: <1558452877-27822-1-git-send-email-pmorel@linux.ibm.com> From: Tony Krowiak Date: Thu, 23 May 2019 11:36:12 -0400 MIME-Version: 1.0 In-Reply-To: <1558452877-27822-1-git-send-email-pmorel@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Message-Id: <5b46f988-fa79-4d84-c81f-144daa0c4426@linux.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: To: Pierre Morel , borntraeger@de.ibm.com Cc: alex.williamson@redhat.com, cohuck@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, frankja@linux.ibm.com, pasic@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com, mimu@linux.ibm.com On 5/21/19 11:34 AM, Pierre Morel wrote: > This patch series implements PQAP/AQIC interception in KVM. > > 1) Data to handle GISA interrupt for AQIC > > To implement this we need to add a new structure, vfio_ap_queue, > to be able to retrieve the mediated device associated with a queue > and specific values needed to register/unregister the interrupt > structures: > - APQN: to be able to issue the commands and search for queue > structures > - saved NIB : to keep track of the pin page for unpining it > - saved ISC : to unregister with the GIB interface > - matrix_mdev: to retrieve the associate matrix, the mediated device > and KVM > > Specific handling bei keeping old values when re-registering is > needed because the guest could unregister interrupt in a invisble > manner bei issuing an un-interceptible RESET command. > > Reset commands issued directly by the guest and indirectly when > removing the guest unpin the memory and deregister the ISC. > > The vfio_ap_queue is associated to the ap_device during the probe > of the device and dissociated during the remove of the ap_device. > > The vfio_ap_queue is associated to the matrix mediated device during > each interception of the AQIC command, so it does not need to be > dissociated until the guest is terminated. > > The life of the vfio_ap_queue will be protected by the matrix_dev lock > to guaranty that no change can occur to the CRYCB or that devices can > not be removed when a vfio_ap_queue is in use. > > 2) KVM destroy race conditions > > To make sure that KVM do not vanish and GISA is still available > when the VFIO_AP driver is in used we take a reference to KVM > during the opening of the mediated device and release it on > releasing the mediated device. > > 3) Interception of PQAP > > The driver registers a hook structure to KVM providing: > - a pointer to a function implementing PQAP(AQIC) handling > - the reference to the module owner of the hook > > On interception by KVM we do not change the behavior, returning > -EOPNOTSUPP to the user in the case AP instructions are not > supported by the host or by the guest. > Otherwise we verify the exceptions cases before trying to call > the vfio_ap hook. > > In the case we do not find a hook we assume that the CRYCB has not > been setup for the guest and is empty. > > 4) Enabling and disabling the IRQ > > When enabling the IRQ care is taken to unping the saved NIB. > When disabling IRQ care is taken to wait until the IRQ bit > of the queue status is cleared before unpining the NIB. > > On RESET and before unpinning the NIB and unregistering the ISC > the IRQ is disabled using PQAP/AQIC even when a PQAP/APZQ have > been done. > > 5) Removing the AP device > > Removing the AP device without having unassign it is clearly > discourage by the documentation. > The patch series does not check if the queue is used by a > guest. It only de-register the IRQ, unregister ISC and unpin > the NIB, then free the vfio_ap_queue. > > 6) Associated QEMU patch > > There is a QEMU patch which is needed to enable the PQAP/AQIC > facility in the guest. > > Posted in qemu-devel@nongnu.org as: > Message-Id: <1550146494-21085-1-git-send-email-pmorel@linux.ibm.com> > > 7) Compatibility with Dynamic configuration patches > > Tony, I did not rebase this series above the dynamic configuration > patches because: > - This series do the work it needs to do without having to take > care on the dynamic configuration. > - It is guarantied that interrupt will be shut off after removing > the APQueue device > - The dynamic configuration series is not converging. Would you consider the following? * Take dynconfig patch "s390: vfio-ap: wait for queue empty on queue reset" and include it in your series. This patch modifies the reset function to wait for queue empty. * In dynconfig patch "s390: vfio-ap: handle bind and unbind of AP queue device" the following functions are introduced: void vfio_ap_mdev_probe_queue(struct ap_queue *queue) void vfio_ap_mdev_remove_queue(struct ap_queue *queue) The vfio_ap_mdev_probe_queue function is called from the vfio_ap driver probe callback. You could embed the code you've introduced in the probe callback there. Of course, you would need to return int from the function for the -ENOMEM error. The vfio_ap_mdev_remove_queue function is called from the vfio_ap driver remove callback. You could embed the code you've introduced in the remove callback there. * Move your vfio_ap_irq_disable function to vfio_ap_ops.c and make it a static function. * Leave the vfio_ap_mdev_reset_queue function as a static function in vfio_ap_ops.c If you do the things above, then I can base the dynconfig series on the IRQ series without much of a merge issue. What say you? Note: I've included review comments for patch 3/4 to match the suggestions above. > > However Tony, the choice is your's, I won't be able to help > in a near future. > > > Pierre Morel (4): > s390: ap: kvm: add PQAP interception for AQIC > vfio: ap: register IOMMU VFIO notifier > s390: ap: implement PAPQ AQIC interception in kernel > s390: ap: kvm: Enable PQAP/AQIC facility for the guest > > arch/s390/include/asm/kvm_host.h | 7 + > arch/s390/kvm/priv.c | 86 ++++++++ > arch/s390/tools/gen_facilities.c | 1 + > drivers/s390/crypto/vfio_ap_drv.c | 34 ++- > drivers/s390/crypto/vfio_ap_ops.c | 379 +++++++++++++++++++++++++++++++++- > drivers/s390/crypto/vfio_ap_private.h | 15 ++ > 6 files changed, 514 insertions(+), 8 deletions(-) >