From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 24 Dec 2020 06:03:25 +0100 From: Halil Pasic Subject: Re: [PATCH v5] s390/vfio-ap: clean up vfio_ap resources when KVM pointer invalidated Message-ID: <20201224060325.2170d7e9.pasic@linux.ibm.com> In-Reply-To: <20201223012013.5418-1-akrowiak@linux.ibm.com> References: <20201223012013.5418-1-akrowiak@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit List-ID: To: Tony Krowiak Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, stable@vger.kernel.org, borntraeger@de.ibm.com, cohuck@redhat.com, kwankhede@nvidia.com, pbonzini@redhat.com, alex.williamson@redhat.com, pasic@linux.vnet.ibm.com On Tue, 22 Dec 2020 20:20:13 -0500 Tony Krowiak wrote: > The vfio_ap device driver registers a group notifier with VFIO when the > file descriptor for a VFIO mediated device for a KVM guest is opened to > receive notification that the KVM pointer is set (VFIO_GROUP_NOTIFY_SET_KVM > event). When the KVM pointer is set, the vfio_ap driver takes the > following actions: > 1. Stashes the KVM pointer in the vfio_ap_mdev struct that holds the state > of the mediated device. > 2. Calls the kvm_get_kvm() function to increment its reference counter. > 3. Sets the function pointer to the function that handles interception of > the instruction that enables/disables interrupt processing. > 4. Sets the masks in the KVM guest's CRYCB to pass AP resources through to > the guest. > > In order to avoid memory leaks, when the notifier is called to receive > notification that the KVM pointer has been set to NULL, the vfio_ap device > driver should reverse the actions taken when the KVM pointer was set. > > Fixes: 258287c994de ("s390: vfio-ap: implement mediated device open callback") > Cc: stable@vger.kernel.org > Signed-off-by: Tony Krowiak > Reviewed-by: Halil Pasic > Reviewed-by: Cornelia Huck LGTM. Christian, you wanted to pick this yourself directly, or? I think we are good to go!