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Message-Id: <a47e980e-95e5-f44c-b8fd-e8a7d3d9b625@linux.ibm.com>
Date: Mon, 6 May 2019 15:53:09 -0400
From: Tony Krowiak <akrowiak@...ux.ibm.com>
To: pmorel@...ux.ibm.com, linux-s390@...r.kernel.org,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc: freude@...ux.ibm.com, borntraeger@...ibm.com, cohuck@...hat.com,
frankja@...ux.ibm.com, david@...hat.com, schwidefsky@...ibm.com,
heiko.carstens@...ibm.com, pasic@...ux.ibm.com,
alex.williamson@...hat.com, kwankhede@...dia.com
Subject: Re: [PATCH v2 2/7] s390: vfio-ap: maintain a shadow of the guest's
CRYCB
On 5/6/19 2:49 AM, Pierre Morel wrote:
> On 03/05/2019 23:14, Tony Krowiak wrote:
>> This patch introduces a shadow of the CRYCB being used by a guest. This
>> will enable to more effectively manage dynamic changes to the AP
>> resources installed on the host that may be assigned to an mdev device
>> and being used by a guest. For example:
>>
>> * AP adapter cards can be dynamically added to and removed from the AP
>> configuration via the SE or an SCLP command.
>>
>> * AP resources that disappear and reappear due to hardware malfunctions.
>>
>> * AP queues bound to and unbound from the vfio_ap device driver by a
>> root user.
>>
>> Signed-off-by: Tony Krowiak <akrowiak@...ux.ibm.com>
>> ---
>> drivers/s390/crypto/vfio_ap_ops.c | 91
>> ++++++++++++++++++++++++++++++++---
>> drivers/s390/crypto/vfio_ap_private.h | 2 +
>> 2 files changed, 87 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
>> b/drivers/s390/crypto/vfio_ap_ops.c
>> index b88a2a2ba075..44a04b4aa9ae 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -297,6 +297,45 @@ static void vfio_ap_mdev_wait_for_qempty(unsigned
>> long apid, unsigned long apqi)
>> } while (--retry);
>> }
>> +/*
>> + * vfio_ap_mdev_update_crycb
>> + *
>> + * @matrix_mdev: the mediated matrix device
>> + *
>> + * Updates the AP matrix in the guest's CRYCB from it's shadow masks.
>> + *
>> + * Returns zero if the guest's CRYCB is successfully updated; otherwise,
>> + * returns -ENODEV if a guest is not running or does not have a CRYCB.
>> + */
>> +static int vfio_ap_mdev_update_crycb(struct ap_matrix_mdev *matrix_mdev)
>> +{
>> + if (!matrix_mdev->kvm || !matrix_mdev->kvm->arch.crypto.crycbd)
>> + return -ENODEV;
>> +
>> + kvm_arch_crypto_set_masks(matrix_mdev->kvm,
>> + matrix_mdev->shadow_crycb->apm,
>> + matrix_mdev->shadow_crycb->aqm,
>> + matrix_mdev->shadow_crycb->adm);
>> +
>> + return 0;
>> +}
>> +
>> +static int match_apqn(struct device *dev, void *data)
>> +{
>> + struct ap_queue *apq = to_ap_queue(dev);
>> +
>> + return (apq->qid == *(unsigned long *)(data)) ? 1 : 0;
>> +}
>> +
>> +static struct device *vfio_ap_get_queue_dev(unsigned long apid,
>> + unsigned long apqi)
>> +{
>> + unsigned long apqn = AP_MKQID(apid, apqi);
>> +
>> + return driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL,
>> + &apqn, match_apqn);
>> +}
>> +
>> /**
>> * assign_adapter_store
>> *
>> @@ -805,14 +844,9 @@ static int vfio_ap_mdev_group_notifier(struct
>> notifier_block *nb,
>> if (ret)
>> return NOTIFY_DONE;
>> - /* If there is no CRYCB pointer, then we can't copy the masks */
>> - if (!matrix_mdev->kvm->arch.crypto.crycbd)
>> + if (vfio_ap_mdev_update_crycb(matrix_mdev))
>> return NOTIFY_DONE;
>> - kvm_arch_crypto_set_masks(matrix_mdev->kvm, matrix_mdev->matrix.apm,
>> - matrix_mdev->matrix.aqm,
>> - matrix_mdev->matrix.adm);
>> -
>> return NOTIFY_OK;
>> }
>> @@ -867,12 +901,55 @@ static int vfio_ap_mdev_reset_queues(struct
>> mdev_device *mdev)
>> return rc;
>> }
>> +static int vfio_ap_mdev_create_shadow_crycb(struct ap_matrix_mdev
>> *matrix_mdev)
>> +{
>> + unsigned long apid, apqi, domid;
>> + struct device *dev;
>> +
>> + matrix_mdev->shadow_crycb =
>> kzalloc(sizeof(*matrix_mdev->shadow_crycb),
>> + GFP_KERNEL);
>> + if (!matrix_mdev->shadow_crycb)
>> + return -ENOMEM;
>> +
>> + vfio_ap_matrix_init(&matrix_dev->info, matrix_mdev->shadow_crycb);
>> +
>> + /*
>> + * Examine each APQN assigned to the mdev device. Set the APID
>> and APQI
>> + * in the shadow CRYCB if and only if the queue device identified by
>> + * the APQN is in the configuration.
>> + */
>> + for_each_set_bit_inv(apid, matrix_mdev->matrix.apm,
>> + matrix_mdev->matrix.apm_max + 1) {
>> + for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm,
>> + matrix_mdev->matrix.aqm_max + 1) {
>> + dev = vfio_ap_get_queue_dev(apid, apqi);
>> + if (dev) {
>> + set_bit_inv(apid,
>> + matrix_mdev->shadow_crycb->apm);
>> + set_bit_inv(apqi,
>> + matrix_mdev->shadow_crycb->aqm);
>> + put_device(dev);
>> + }
>
> I think that if we do not find a device here we have a problem.
> Don't we?
Other than the fact that the guest will not have any AP devices,
what would be the problem? What would you suggest?
>
>
>> + }
>> + }
>> +
>> + /* Set all control domains assigned to the mdev in the shadow
>> CRYCB */
>> + for_each_set_bit_inv(domid, matrix_mdev->matrix.adm,
>> + matrix_mdev->matrix.adm_max + 1)
>> + set_bit_inv(domid, matrix_mdev->shadow_crycb->adm);
>> +
>> + return 0;
>> +}
>> +
>> static int vfio_ap_mdev_open(struct mdev_device *mdev)
>> {
>> struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
>> unsigned long events;
>> int ret;
>> + ret = vfio_ap_mdev_create_shadow_crycb(matrix_mdev);
>> + if (ret)
>> + return ret;
>> if (!try_module_get(THIS_MODULE))
>> return -ENODEV;
>> @@ -902,6 +979,8 @@ static void vfio_ap_mdev_release(struct
>> mdev_device *mdev)
>> &matrix_mdev->group_notifier);
>> matrix_mdev->kvm = NULL;
>> module_put(THIS_MODULE);
>> + kfree(matrix_mdev->shadow_crycb);
>> + matrix_mdev->shadow_crycb = NULL;
>> }
>> static int vfio_ap_mdev_get_device_info(unsigned long arg)
>> diff --git a/drivers/s390/crypto/vfio_ap_private.h
>> b/drivers/s390/crypto/vfio_ap_private.h
>> index 76b7f98e47e9..e8457aa61976 100644
>> --- a/drivers/s390/crypto/vfio_ap_private.h
>> +++ b/drivers/s390/crypto/vfio_ap_private.h
>> @@ -72,6 +72,7 @@ struct ap_matrix {
>> * @list: allows the ap_matrix_mdev struct to be added to a list
>> * @matrix: the adapters, usage domains and control domains
>> assigned to the
>> * mediated matrix device.
>> + * @shadow_crycb: a shadow copy of the crycb in use by a guest
>> * @group_notifier: notifier block used for specifying callback
>> function for
>> * handling the VFIO_GROUP_NOTIFY_SET_KVM event
>> * @kvm: the struct holding guest's state
>> @@ -79,6 +80,7 @@ struct ap_matrix {
>> struct ap_matrix_mdev {
>> struct list_head node;
>> struct ap_matrix matrix;
>> + struct ap_matrix *shadow_crycb;
>> struct notifier_block group_notifier;
>> struct kvm *kvm;
>> };
>>
>
>
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