From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Jason Gunthorpe <jgg@nvidia.com>, Tony Krowiak <akrowiak@linux.ibm.com>
Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
cohuck@redhat.com, pasic@linux.vnet.ibm.com,
jjherne@linux.ibm.com, alex.williamson@redhat.com,
kwankhede@nvidia.com, frankja@linux.ibm.com, david@redhat.com,
imbrenda@linux.ibm.com, hca@linux.ibm.com
Subject: Re: [PATCH 1/3] s390/vfio-ap: clean up mdev resources when remove callback invoked
Date: Tue, 15 Jun 2021 09:43:44 +0200 [thread overview]
Message-ID: <fb6a3aa4-c12b-5b38-54a5-36941d5d8dbd@de.ibm.com> (raw)
In-Reply-To: <20210611164854.GT1002214@nvidia.com>
On 11.06.21 18:48, Jason Gunthorpe wrote:
> On Wed, Jun 09, 2021 at 06:46:32PM -0400, Tony Krowiak wrote:
>> The mdev remove callback for the vfio_ap device driver bails out with
>> -EBUSY if the mdev is in use by a KVM guest (i.e., the KVM pointer in the
>> struct ap_matrix_mdev is not NULL). The intended purpose was
>> to prevent the mdev from being removed while in use. There are two
>> problems with this scenario:
>>
>> 1. Returning a non-zero return code from the remove callback does not
>> prevent the removal of the mdev.
>>
>> 2. The KVM pointer in the struct ap_matrix_mdev will always be NULL because
>> the remove callback will not get invoked until the mdev fd is closed.
>> When the mdev fd is closed, the mdev release callback is invoked and
>> clears the KVM pointer from the struct ap_matrix_mdev.
>>
>> Let's go ahead and remove the check for KVM in the remove callback and
>> allow the cleanup of mdev resources to proceed.
>>
>> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
>> ---
>> drivers/s390/crypto/vfio_ap_ops.c | 10 ----------
>> 1 file changed, 10 deletions(-)
>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Jason, I guess you want this patch still in 5.13, the other 2 can be 5.14?
next prev parent reply other threads:[~2021-06-15 7:44 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 22:46 [PATCH 0/3] s390/vfio-ap: refactor mdev remove callback and locks Tony Krowiak
2021-06-09 22:46 ` [PATCH 1/3] s390/vfio-ap: clean up mdev resources when remove callback invoked Tony Krowiak
2021-06-11 16:48 ` Jason Gunthorpe
2021-06-14 17:29 ` Tony Krowiak
2021-06-15 7:43 ` Christian Borntraeger [this message]
2021-06-09 22:46 ` [PATCH 2/3] s390/vfio-ap: introduce two new r/w locks to replace wait_queue_head_t Tony Krowiak
2021-06-11 17:05 ` Jason Gunthorpe
2021-06-11 17:11 ` David Hildenbrand
2021-06-11 17:41 ` Jason Gunthorpe
2021-06-09 22:46 ` [PATCH 3/3] s390/vfio-ap: r/w lock for PQAP interception handler function pointer Tony Krowiak
2021-06-11 17:06 ` Jason Gunthorpe
2021-06-15 8:55 ` Christian Borntraeger
2021-06-15 18:08 ` Tony Krowiak
2021-06-15 18:55 ` Tony Krowiak
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