Re: [PATCH v2 1/1] s390/vfio-ap: fix circular lockdep when setting/clearing crypto masks

From: Christian Borntraeger
Date: Wed Feb 24 2021 - 11:16:39 EST




On 23.02.21 10:48, Halil Pasic wrote:
> On Mon, 15 Feb 2021 20:15:47 -0500
> Tony Krowiak <akrowiak@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx>

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