[PATCH v2 2/7] s390: vfio-ap: maintain a shadow of the guest's CRYCB

Tony Krowiak
2019-05-03T21:14:28Z

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);
+ }
+ }
+ }
+
+ /* 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;
};
--
2.7.4