Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v2 1/1] s390/vfio-ap: fix circular lockdep when
 setting/clearing crypto masks
To:     Halil Pasic <pasic@linux.ibm.com>,
        Tony Krowiak <akrowiak@linux.ibm.com>
Cc:     linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, stable@vger.kernel.org, cohuck@redhat.com,
        kwankhede@nvidia.com, pbonzini@redhat.com,
        alex.williamson@redhat.com, pasic@linux.vnet.ibm.com
References: <20210216011547.22277-1-akrowiak@linux.ibm.com>
 <20210216011547.22277-2-akrowiak@linux.ibm.com>
 <20210223104805.6a8d1872.pasic@linux.ibm.com>
From:   Christian Borntraeger <borntraeger@de.ibm.com>
Message-ID: <e07d6f8e-f29e-7c4e-4226-5a5c072e7ae6@de.ibm.com>
Date:   Wed, 24 Feb 2021 17:10:40 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.7.0
MIME-Version: 1.0
In-Reply-To: <20210223104805.6a8d1872.pasic@linux.ibm.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 23.02.21 10:48, Halil Pasic wrote:
> On Mon, 15 Feb 2021 20:15:47 -0500
> Tony Krowiak <akrowiak@linux.ibm.com> wrote:
> 
>> This patch fixes a circular locking dependency in the CI introduced by
>> commit f21916ec4826 ("s390/vfio-ap: clean up vfio_ap resources when KVM
>> pointer invalidated"). The lockdep only occurs when starting a Secure
>> Execution guest. Crypto virtualization (vfio_ap) is not yet supported for
>> SE guests; however, in order to avoid CI errors, this fix is being
>> provided.
>>
>> The circular lockdep was introduced when the masks in the guest's APCB
>> were taken under the matrix_dev->lock. While the lock is definitely
>> needed to protect the setting/unsetting of the KVM pointer, it is not
>> necessarily critical for setting the masks, so this will not be done under
>> protection of the matrix_dev->lock.
> 
> 
> 
> With the one little thing I commented on below addressed: 
> Acked-by: Halil Pasic <pasic@linux.ibm.com>  

Tony, can you comment on Halils comment or send a v3 right away?