From: Tony Krowiak <akrowiak@linux.ibm.com>
To: Halil Pasic <pasic@linux.ibm.com>,
Tony Krowiak <akrowiak@linux.vnet.ibm.com>,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org
Cc: freude@de.ibm.com, schwidefsky@de.ibm.com,
heiko.carstens@de.ibm.com, borntraeger@de.ibm.com,
cohuck@redhat.com, kwankhede@nvidia.com,
bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com,
alex.williamson@redhat.com, pmorel@linux.vnet.ibm.com,
alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com,
jjherne@linux.vnet.ibm.com, thuth@redhat.com,
pasic@linux.vnet.ibm.com, berrange@redhat.com,
fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com,
frankja@linux.ibm.com
Subject: Re: [PATCH v10 11/26] s390: vfio-ap: implement mediated device open callback
Date: Tue, 18 Sep 2018 17:57:31 -0400 [thread overview]
Message-ID: <bc642c76-09e2-586e-b512-55f1679beb0c@linux.ibm.com> (raw)
In-Reply-To: <0ba9647d-76d8-1a6c-bed0-fadd0af496cc@linux.ibm.com>
On 09/18/2018 01:00 PM, Halil Pasic wrote:
>
> On 09/12/2018 09:43 PM, Tony Krowiak wrote:
>> +/**
>> + * vfio_ap_mdev_open_once
>> + *
>> + * @matrix_mdev: a mediated matrix device
>> + *
>> + * Return 0 if no other mediated matrix device has been opened for the
>> + * KVM guest assigned to @matrix_mdev; otherwise, returns an error.
>> + */
>> +static int vfio_ap_mdev_open_once(struct ap_matrix_mdev *matrix_mdev,
>> + struct kvm *kvm)
>> +{
>> + struct ap_matrix_mdev *m;
>> +
>> + mutex_lock(&matrix_dev->lock);
>> +
>> + list_for_each_entry(m, &matrix_dev->mdev_list, node) {
>> + if ((m != matrix_mdev) && (m->kvm == kvm)) {
>> + mutex_unlock(&matrix_dev->lock);
>> + return -EPERM;
>> + }
>> + }
>> +
>> + mutex_unlock(&matrix_dev->lock);
>> +
>> + return 0;
>> +}
>> +
>> +static int vfio_ap_mdev_group_notifier(struct notifier_block *nb,
>> + unsigned long action, void *data)
>> +{
>> + int ret;
>> + struct ap_matrix_mdev *matrix_mdev;
>> +
>> + if (action != VFIO_GROUP_NOTIFY_SET_KVM)
>> + return NOTIFY_OK;
>> +
>> + matrix_mdev = container_of(nb, struct ap_matrix_mdev, group_notifier);
>> +
>> + if (!data) {
>> + matrix_mdev->kvm = NULL;
>> + return NOTIFY_OK;
>> + }
>> +
>> + ret = vfio_ap_mdev_open_once(matrix_mdev, data);
> This could be racy. Two threads doing vfio_ap_mdev_group_notifier()
> can first get 0 here in a sense that there is no such kvm in the list,
> and then both set the very same kvm three lines below. Which would
> result in what we are trying to prevent.
>
> Also vfio_ap_mdev_open_once() does not seem like an appropriate name
> any more. If we were to do the matrix_mdev->kvm = kvm in there we could
> call it something like vfio_ap_mdev_set_kvm().
I'm moving the matrix-mdev->kvm = kvm inside the mutex lock in
vfio_ap_mdev_open_once() ... also renaming it to vfio_ap_mdev_set_kvm().
>
>> + if (ret)
>> + return NOTIFY_DONE;
>> +
>> + matrix_mdev->kvm = data;
>> +
>> + ret = kvm_ap_validate_crypto_setup(matrix_mdev->kvm);
>> + if (ret)
>> + return ret;
>> +
>> + vfio_ap_mdev_copy_masks(matrix_mdev);
>> +
>> + return NOTIFY_OK;
>> +}
next prev parent reply other threads:[~2018-09-18 21:57 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-12 19:42 [PATCH v10 00/26] guest dedicated crypto adapters Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 01/26] KVM: s390: vsie: simulate VCPU SIE entry/exit Tony Krowiak
2018-09-24 10:32 ` Christian Borntraeger
2018-09-24 16:53 ` Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 02/26] KVM: s390: introduce and use KVM_REQ_VSIE_RESTART Tony Krowiak
2018-09-24 10:49 ` Christian Borntraeger
2018-09-24 16:48 ` Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 03/26] KVM: s390: refactor crypto initialization Tony Krowiak
2018-09-21 23:18 ` Tony Krowiak
2018-09-24 8:35 ` David Hildenbrand
2018-09-24 10:34 ` Cornelia Huck
2018-09-12 19:42 ` [PATCH v10 04/26] s390: vfio-ap: base implementation of VFIO AP device driver Tony Krowiak
2018-09-20 15:31 ` Cornelia Huck
2018-09-20 15:53 ` Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 05/26] s390: vfio-ap: register matrix device with VFIO mdev framework Tony Krowiak
2018-09-20 15:50 ` Cornelia Huck
2018-09-20 20:35 ` Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 06/26] s390: vfio-ap: sysfs interfaces to configure adapters Tony Krowiak
2018-09-21 9:40 ` Cornelia Huck
2018-09-21 9:52 ` Harald Freudenberger
2018-09-21 14:07 ` Tony Krowiak
2018-09-12 19:42 ` [PATCH v10 07/26] s390: vfio-ap: sysfs interfaces to configure domains Tony Krowiak
2018-09-24 10:45 ` Cornelia Huck
2018-09-12 19:42 ` [PATCH v10 08/26] s390: vfio-ap: sysfs interfaces to configure control domains Tony Krowiak
2018-09-24 10:57 ` Cornelia Huck
2018-09-12 19:42 ` [PATCH v10 09/26] s390: vfio-ap: sysfs interface to view matrix mdev matrix Tony Krowiak
2018-09-24 10:59 ` Cornelia Huck
2018-09-12 19:43 ` [PATCH v10 10/26] KVM: s390: interfaces to clear CRYCB masks Tony Krowiak
2018-09-24 11:01 ` Cornelia Huck
2018-09-24 11:50 ` Halil Pasic
2018-09-24 12:01 ` Cornelia Huck
2018-09-24 15:33 ` Tony Krowiak
2018-09-24 14:49 ` Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 11/26] s390: vfio-ap: implement mediated device open callback Tony Krowiak
2018-09-18 17:00 ` Halil Pasic
2018-09-18 21:57 ` Tony Krowiak [this message]
2018-09-21 23:28 ` Tony Krowiak
2018-09-24 8:40 ` David Hildenbrand
2018-09-24 16:07 ` Tony Krowiak
2018-09-24 18:40 ` David Hildenbrand
2018-09-24 18:43 ` Tony Krowiak
2018-09-24 19:46 ` Tony Krowiak
2018-09-24 19:55 ` David Hildenbrand
2018-09-25 19:54 ` Tony Krowiak
2018-09-25 19:55 ` David Hildenbrand
2018-09-12 19:43 ` [PATCH v10 12/26] s390: vfio-ap: implement VFIO_DEVICE_GET_INFO ioctl Tony Krowiak
2018-09-24 11:43 ` Cornelia Huck
2018-09-24 16:29 ` Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 13/26] s390: vfio-ap: zeroize the AP queues Tony Krowiak
2018-09-24 11:36 ` Cornelia Huck
2018-09-24 12:16 ` Halil Pasic
2018-09-24 12:32 ` Cornelia Huck
2018-09-24 13:22 ` Harald Freudenberger
2018-09-24 16:42 ` Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 14/26] s390: vfio-ap: implement VFIO_DEVICE_RESET ioctl Tony Krowiak
2018-09-24 11:43 ` Cornelia Huck
2018-09-12 19:43 ` [PATCH v10 15/26] KVM: s390: Clear Crypto Control Block when using vSIE Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 16/26] KVM: s390: vsie: Do the CRYCB validation first Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 17/26] KVM: s390: vsie: Make use of CRYCB FORMAT2 clear Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 18/26] KVM: s390: vsie: Allow CRYCB FORMAT-2 Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 19/26] KVM: s390: vsie: allow CRYCB FORMAT-1 Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 20/26] KVM: s390: vsie: allow CRYCB FORMAT-0 Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 21/26] KVM: s390: vsie: allow guest FORMAT-0 CRYCB on host FORMAT-1 Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 22/26] KVM: s390: vsie: allow guest FORMAT-1 CRYCB on host FORMAT-2 Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 23/26] KVM: s390: vsie: allow guest FORMAT-0 " Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 24/26] KVM: s390: device attrs to enable/disable AP interpretation Tony Krowiak
2018-09-17 8:51 ` David Hildenbrand
2018-09-21 23:40 ` Tony Krowiak
2018-09-24 11:23 ` David Hildenbrand
2018-09-24 16:25 ` Tony Krowiak
2018-09-24 18:42 ` Tony Krowiak
2018-09-24 18:51 ` David Hildenbrand
2018-09-25 13:24 ` Tony Krowiak
2018-09-25 7:32 ` David Hildenbrand
2018-09-25 13:26 ` Tony Krowiak
2018-09-24 18:46 ` David Hildenbrand
2018-09-25 13:31 ` Tony Krowiak
2018-09-12 19:43 ` [PATCH v10 25/26] KVM: s390: CPU model support for AP virtualization Tony Krowiak
2018-09-21 23:31 ` Tony Krowiak
2018-09-24 8:33 ` David Hildenbrand
2018-09-12 19:43 ` [PATCH v10 26/26] s390: doc: detailed specifications " Tony Krowiak
2018-09-24 10:10 ` [PATCH v10 00/26] guest dedicated crypto adapters Christian Borntraeger
2018-09-24 11:53 ` Cornelia Huck
2018-09-24 16:46 ` Tony Krowiak
2018-09-24 16:50 ` Tony Krowiak
2018-09-24 11:49 ` Cornelia Huck
2018-09-24 16:45 ` Tony Krowiak
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