Messages in this thread | | | Subject | Re: [PATCH v2 2/7] s390: vfio-ap: maintain a shadow of the guest's CRYCB | From | Pierre Morel <> | Date | Tue, 7 May 2019 10:22:06 +0200 |
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On 06/05/2019 21:53, Tony Krowiak wrote: > 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@linux.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? >
Suppose we have in matrix_mdev->matrix: 1-2 1-3 2-2 2-3
We set the shadow_crycb with: we find 1-2 we set 1 2 we find 1-3 we se 1 3 we find 2-2 we set 2 2 we do not find 2-3
we have set apm(1,2) aqm(2,3) the guest can access 2-3 but we do not have the device.
Pierre
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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