From: Jason Gunthorpe <jgg@nvidia.com>
To: Tony Krowiak <akrowiak@linux.ibm.com>
Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
borntraeger@de.ibm.com, 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 3/3] s390/vfio-ap: r/w lock for PQAP interception handler function pointer
Date: Fri, 11 Jun 2021 14:06:10 -0300 [thread overview]
Message-ID: <20210611170610.GV1002214@nvidia.com> (raw)
In-Reply-To: <20210609224634.575156-4-akrowiak@linux.ibm.com>
On Wed, Jun 09, 2021 at 06:46:34PM -0400, Tony Krowiak wrote:
> The function pointer to the interception handler for the PQAP instruction
> can get changed during the interception process. Let's add a
> semaphore to struct kvm_s390_crypto to control read/write access to the
> function pointer contained therein.
>
> The semaphore must be locked for write access by the vfio_ap device driver
> when notified that the KVM pointer has been set or cleared. It must be
> locked for read access by the interception framework when the PQAP
> instruction is intercepted.
>
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> ---
> arch/s390/include/asm/kvm_host.h | 6 +++---
> arch/s390/kvm/kvm-s390.c | 1 +
> arch/s390/kvm/priv.c | 6 +++---
> drivers/s390/crypto/vfio_ap_ops.c | 14 ++++++++++----
> drivers/s390/crypto/vfio_ap_private.h | 2 +-
> 5 files changed, 18 insertions(+), 11 deletions(-)
This is alot better than the try_module_get!
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Jason
next prev parent reply other threads:[~2021-06-11 17:06 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
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 [this message]
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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