Re: [PATCH v2 2/7] s390: vfio-ap: maintain a shadow of the guest's CRYCB
From: Tony Krowiak
Date: Mon May 06 2019 - 15:54:04 EST
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
ÂÂ 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
ÂÂ root user.
Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
---
 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)
ÂÂÂÂÂ } 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)
+{
+ÂÂÂ if (!matrix_mdev->kvm || !matrix_mdev->kvm->arch.crypto.crycbd)
+ÂÂÂÂÂÂÂ return -ENODEV;
+
+ÂÂÂ kvm_arch_crypto_set_masks(matrix_mdev->kvm,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ matrix_mdev->shadow_crycb->apm,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ matrix_mdev->shadow_crycb->aqm,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ matrix_mdev->shadow_crycb->adm);
+
+ÂÂÂ return 0;
+}
+
+static int match_apqn(struct device *dev, void *data)
+{
+ÂÂÂ struct ap_queue *apq = to_ap_queue(dev);
+
+ÂÂÂ return (apq->qid == *(unsigned long *)(data)) ? 1 : 0;
+}
+
+static struct device *vfio_ap_get_queue_dev(unsigned long apid,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ unsigned long apqi)
+{
+ÂÂÂ unsigned long apqn = AP_MKQID(apid, apqi);
+
+ÂÂÂ return driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ &apqn, match_apqn);
+}
+
 /**
ÂÂ * assign_adapter_store
ÂÂ *
@@ -805,14 +844,9 @@ static int vfio_ap_mdev_group_notifier(struct
notifier_block *nb,
ÂÂÂÂÂ if (ret)
ÂÂÂÂÂÂÂÂÂ return NOTIFY_DONE;
-ÂÂÂ /* If there is no CRYCB pointer, then we can't copy the masks */
-ÂÂÂ if (!matrix_mdev->kvm->arch.crypto.crycbd)
+ÂÂÂ if (vfio_ap_mdev_update_crycb(matrix_mdev))
ÂÂÂÂÂÂÂÂÂ return NOTIFY_DONE;
-ÂÂÂ kvm_arch_crypto_set_masks(matrix_mdev->kvm, matrix_mdev->matrix.apm,
-ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ matrix_mdev->matrix.aqm,
-ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ matrix_mdev->matrix.adm);
-
ÂÂÂÂÂ return NOTIFY_OK;
 }
@@ -867,12 +901,55 @@ static int vfio_ap_mdev_reset_queues(struct
mdev_device *mdev)
ÂÂÂÂÂ return rc;
 }
+static int vfio_ap_mdev_create_shadow_crycb(struct ap_matrix_mdev
*matrix_mdev)
+{
+ÂÂÂ unsigned long apid, apqi, domid;
+ÂÂÂ struct device *dev;
+
+ÂÂÂ matrix_mdev->shadow_crycb =
kzalloc(sizeof(*matrix_mdev->shadow_crycb),
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ GFP_KERNEL);
+ÂÂÂ if (!matrix_mdev->shadow_crycb)
+ÂÂÂÂÂÂÂ return -ENOMEM;
+
+ÂÂÂ vfio_ap_matrix_init(&matrix_dev->info, matrix_mdev->shadow_crycb);
+
+ÂÂÂ /*
+ÂÂÂÂ * Examine each APQN assigned to the mdev device. Set the APID
and APQI
+ÂÂÂÂ * in the shadow CRYCB if and only if the queue device identified by
+ÂÂÂÂ * the APQN is in the configuration.
+ÂÂÂÂ */
+ÂÂÂ for_each_set_bit_inv(apid, matrix_mdev->matrix.apm,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ matrix_mdev->matrix.apm_max + 1) {
+ÂÂÂÂÂÂÂ for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ matrix_mdev->matrix.aqm_max + 1) {
+ÂÂÂÂÂÂÂÂÂÂÂ dev = vfio_ap_get_queue_dev(apid, apqi);
+ÂÂÂÂÂÂÂÂÂÂÂ if (dev) {
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ set_bit_inv(apid,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ matrix_mdev->shadow_crycb->apm);
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ set_bit_inv(apqi,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ matrix_mdev->shadow_crycb->aqm);
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ put_device(dev);
+ÂÂÂÂÂÂÂÂÂÂÂ }
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?
+ÂÂÂÂÂÂÂ }
+ÂÂÂ }
+
+ÂÂÂ /* Set all control domains assigned to the mdev in the shadow
CRYCB */
+ÂÂÂ for_each_set_bit_inv(domid, matrix_mdev->matrix.adm,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ matrix_mdev->matrix.adm_max + 1)
+ÂÂÂÂÂÂÂ set_bit_inv(domid, matrix_mdev->shadow_crycb->adm);
+
+ÂÂÂ return 0;
+}
+
 static int vfio_ap_mdev_open(struct mdev_device *mdev)
 {
ÂÂÂÂÂ struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
ÂÂÂÂÂ unsigned long events;
ÂÂÂÂÂ int ret;
+ÂÂÂ ret = vfio_ap_mdev_create_shadow_crycb(matrix_mdev);
+ÂÂÂ if (ret)
+ÂÂÂÂÂÂÂ return ret;
ÂÂÂÂÂ if (!try_module_get(THIS_MODULE))
ÂÂÂÂÂÂÂÂÂ return -ENODEV;
@@ -902,6 +979,8 @@ static void vfio_ap_mdev_release(struct
mdev_device *mdev)
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ &matrix_mdev->group_notifier);
ÂÂÂÂÂ matrix_mdev->kvm = NULL;
ÂÂÂÂÂ module_put(THIS_MODULE);
+ÂÂÂ kfree(matrix_mdev->shadow_crycb);
+ÂÂÂ 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 {
ÂÂ * @list:ÂÂÂ allows the ap_matrix_mdev struct to be added to a list
ÂÂ * @matrix:ÂÂÂ the adapters, usage domains and control domains
assigned to the
ÂÂ *ÂÂÂÂÂÂÂ mediated matrix device.
+ * @shadow_crycb: a shadow copy of the crycb in use by a guest
ÂÂ * @group_notifier: notifier block used for specifying callback
function for
ÂÂ *ÂÂÂÂÂÂÂÂÂÂÂ handling the VFIO_GROUP_NOTIFY_SET_KVM event
ÂÂ * @kvm:ÂÂÂ the struct holding guest's state
@@ -79,6 +80,7 @@ struct ap_matrix {
 struct ap_matrix_mdev {
ÂÂÂÂÂ struct list_head node;
ÂÂÂÂÂ struct ap_matrix matrix;
+ÂÂÂ struct ap_matrix *shadow_crycb;
ÂÂÂÂÂ struct notifier_block group_notifier;
ÂÂÂÂÂ struct kvm *kvm;
 };