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 <akrow...@linux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c     | 69 ++++++++++++++++++++++++++++++++---
 drivers/s390/crypto/vfio_ap_private.h |  2 +
 2 files changed, 65 insertions(+), 6 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c 
b/drivers/s390/crypto/vfio_ap_ops.c
index 900b9cf20ca5..b0453e6c20d0 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -271,6 +271,29 @@ static int vfio_ap_mdev_verify_no_sharing(struct 
ap_matrix_mdev *matrix_mdev)
        return 0;
 }
 
+/*
+ * 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;
+}
+
 /**
  * assign_adapter_store
  *
@@ -340,6 +363,9 @@ static ssize_t assign_adapter_store(struct device *dev,
        if (ret)
                goto share_err;
 
+       if (matrix_mdev->shadow_crycb)
+               set_bit_inv(apid, matrix_mdev->shadow_crycb->apm);
+
        ret = count;
        goto done;
 
@@ -391,6 +417,9 @@ static ssize_t unassign_adapter_store(struct device *dev,
 
        mutex_lock(&matrix_dev->lock);
        clear_bit_inv((unsigned long)apid, matrix_mdev->matrix.apm);
+
+       if (matrix_mdev->shadow_crycb)
+               clear_bit_inv(apid, matrix_mdev->shadow_crycb->apm);
        mutex_unlock(&matrix_dev->lock);
 
        return count;
@@ -481,6 +510,9 @@ static ssize_t assign_domain_store(struct device *dev,
        if (ret)
                goto share_err;
 
+       if (matrix_mdev->shadow_crycb)
+               set_bit_inv(apqi, matrix_mdev->shadow_crycb->aqm);
+
        ret = count;
        goto done;
 
@@ -533,6 +565,10 @@ static ssize_t unassign_domain_store(struct device *dev,
 
        mutex_lock(&matrix_dev->lock);
        clear_bit_inv((unsigned long)apqi, matrix_mdev->matrix.aqm);
+
+       if (matrix_mdev->shadow_crycb)
+               clear_bit_inv(apqi, matrix_mdev->shadow_crycb->aqm);
+
        mutex_unlock(&matrix_dev->lock);
 
        return count;
@@ -582,6 +618,10 @@ static ssize_t assign_control_domain_store(struct device 
*dev,
         */
        mutex_lock(&matrix_dev->lock);
        set_bit_inv(id, matrix_mdev->matrix.adm);
+
+       if (matrix_mdev->shadow_crycb)
+               set_bit_inv(id, matrix_mdev->shadow_crycb->adm);
+
        mutex_unlock(&matrix_dev->lock);
 
        return count;
@@ -626,6 +666,10 @@ static ssize_t unassign_control_domain_store(struct device 
*dev,
 
        mutex_lock(&matrix_dev->lock);
        clear_bit_inv(domid, matrix_mdev->matrix.adm);
+
+       if (matrix_mdev->shadow_crycb)
+               clear_bit_inv(domid, matrix_mdev->shadow_crycb->adm);
+
        mutex_unlock(&matrix_dev->lock);
 
        return count;
@@ -779,14 +823,9 @@ 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;
 }
 
@@ -838,12 +877,28 @@ 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)
+{
+       matrix_mdev->shadow_crycb = kzalloc(sizeof(*matrix_mdev->shadow_crycb),
+                                           GFP_KERNEL);
+       if (!matrix_mdev->shadow_crycb)
+               return -ENOMEM;
+
+       memcpy(matrix_mdev->shadow_crycb, &matrix_mdev->matrix,
+              sizeof(matrix_mdev->matrix));
+
+       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;
@@ -873,6 +928,8 @@ 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

Reply via email to