From: Cornelia Huck <cohuck@redhat.com>
To: 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,
borntraeger@de.ibm.com, kwankhede@nvidia.com,
pbonzini@redhat.com, alex.williamson@redhat.com,
pasic@linux.vnet.ibm.com
Subject: Re: [PATCH v2 1/1] s390/vfio-ap: fix circular lockdep when setting/clearing crypto masks
Date: Fri, 19 Feb 2021 14:45:54 +0100 [thread overview]
Message-ID: <20210219144554.3857a034.cohuck@redhat.com> (raw)
In-Reply-To: <20210216011547.22277-2-akrowiak@linux.ibm.com>
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.
>
> Fixes: f21916ec4826 ("s390/vfio-ap: clean up vfio_ap resources when KVM pointer invalidated")
> Cc: stable@vger.kernel.org
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> ---
> drivers/s390/crypto/vfio_ap_ops.c | 119 +++++++++++++++++++++---------
> 1 file changed, 84 insertions(+), 35 deletions(-)
I've been looking at the patch for a bit now and tried to follow down
the various paths; and while I think it's ok, I do not really have
enough confidence about that for a R-b. But have an
Acked-by: Cornelia Huck <cohuck@redhat.com>
next prev parent reply other threads:[~2021-02-19 13:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-16 1:15 [PATCH v2 0/1] s390/vfio-ap: fix circular lockdep when staring SE guest Tony Krowiak
2021-02-16 1:15 ` [PATCH v2 1/1] s390/vfio-ap: fix circular lockdep when setting/clearing crypto masks Tony Krowiak
2021-02-19 13:45 ` Cornelia Huck [this message]
2021-02-19 20:49 ` Tony Krowiak
2021-02-23 9:48 ` Halil Pasic
2021-02-24 16:10 ` Christian Borntraeger
2021-02-24 23:44 ` Tony Krowiak
[not found] ` <63bb0d61-efcd-315b-5a1a-0ef4d99600f4@linux.ibm.com>
2021-02-25 11:28 ` Halil Pasic
[not found] ` <f5d5cbab-2181-2a95-8a87-b21d05405936@linux.ibm.com>
2021-02-25 15:25 ` Tony Krowiak
2021-02-25 15:35 ` Halil Pasic
2021-02-25 20:02 ` Tony Krowiak
2021-02-25 15:36 ` Halil Pasic
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