Let's allow adapters, domains and control domains to be assigned to or
unassigned from an AP matrix mdev device while it is in use by a guest.
When an adapter, domain or control domain is assigned to or unassigned
from an mdev device while a guest is using it, the guest's CRYCB will be
updated thus giving access to the resource assigned, or taking access away
from the resource unassigned for the guest.

Signed-off-by: Tony Krowiak <akrow...@linux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c | 68 +++++++++++++++++++--------------------
 1 file changed, 33 insertions(+), 35 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c 
b/drivers/s390/crypto/vfio_ap_ops.c
index cb3e4f7671be..cda1d216ee38 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -155,6 +155,24 @@ 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 the masks configured for the
+ * mediated matrix device via its sysfs interfaces.
+ */
+static void vfio_ap_mdev_update_crycb(struct ap_matrix_mdev *matrix_mdev)
+{
+       if (matrix_mdev->kvm) {
+               kvm_arch_crypto_set_masks(matrix_mdev->kvm,
+                                         matrix_mdev->matrix.apm,
+                                         matrix_mdev->matrix.aqm,
+                                         matrix_mdev->matrix.adm);
+       }
+}
+
 /**
  * assign_adapter_store
  *
@@ -196,10 +214,6 @@ static ssize_t assign_adapter_store(struct device *dev,
        struct mdev_device *mdev = mdev_from_dev(dev);
        struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
 
-       /* If the guest is running, disallow assignment of adapter */
-       if (matrix_mdev->kvm)
-               return -EBUSY;
-
        ret = kstrtoul(buf, 0, &apid);
        if (ret)
                return ret;
@@ -214,16 +228,12 @@ static ssize_t assign_adapter_store(struct device *dev,
         */
        mutex_lock(&matrix_dev->lock);
 
-       ret = vfio_ap_mdev_verify_queues_reserved_for_apid(matrix_mdev, apid);
-       if (ret)
-               goto done;
-
        set_bit_inv(apid, matrix_mdev->matrix.apm);
 
        ret = ap_apqn_in_matrix_owned_by_def_drv(matrix_mdev->matrix.apm,
                                                 matrix_mdev->matrix.aqm);
 
-       /* If any APQN is reserved for used by the default drivers */
+       /* If any APQN is owned by the default drivers */
        ret = (ret == 1) ? -EADDRNOTAVAIL : ret;
        if (ret)
                goto error;
@@ -232,6 +242,7 @@ static ssize_t assign_adapter_store(struct device *dev,
        if (ret)
                goto error;
 
+       vfio_ap_mdev_update_crycb(matrix_mdev);
        ret = count;
        goto done;
 
@@ -270,10 +281,6 @@ static ssize_t unassign_adapter_store(struct device *dev,
        struct mdev_device *mdev = mdev_from_dev(dev);
        struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
 
-       /* If the guest is running, disallow un-assignment of adapter */
-       if (matrix_mdev->kvm)
-               return -EBUSY;
-
        ret = kstrtoul(buf, 0, &apid);
        if (ret)
                return ret;
@@ -283,6 +290,7 @@ static ssize_t unassign_adapter_store(struct device *dev,
 
        mutex_lock(&matrix_dev->lock);
        clear_bit_inv((unsigned long)apid, matrix_mdev->matrix.apm);
+       vfio_ap_mdev_update_crycb(matrix_mdev);
        mutex_unlock(&matrix_dev->lock);
 
        return count;
@@ -331,10 +339,6 @@ static ssize_t assign_domain_store(struct device *dev,
        struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
        unsigned long max_apqi = matrix_mdev->matrix.aqm_max;
 
-       /* If the guest is running, disallow assignment of domain */
-       if (matrix_mdev->kvm)
-               return -EBUSY;
-
        ret = kstrtoul(buf, 0, &apqi);
        if (ret)
                return ret;
@@ -355,12 +359,13 @@ static ssize_t assign_domain_store(struct device *dev,
 
        ret = vfio_ap_mdev_verify_no_sharing(matrix_mdev);
        if (ret)
-               goto share_err;
+               goto error;
 
+       vfio_ap_mdev_update_crycb(matrix_mdev);
        ret = count;
        goto done;
 
-share_err:
+error:
        clear_bit_inv(apqi, matrix_mdev->matrix.aqm);
 done:
        mutex_unlock(&matrix_dev->lock);
@@ -396,10 +401,6 @@ static ssize_t unassign_domain_store(struct device *dev,
        struct mdev_device *mdev = mdev_from_dev(dev);
        struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
 
-       /* If the guest is running, disallow un-assignment of domain */
-       if (matrix_mdev->kvm)
-               return -EBUSY;
-
        ret = kstrtoul(buf, 0, &apqi);
        if (ret)
                return ret;
@@ -409,6 +410,7 @@ static ssize_t unassign_domain_store(struct device *dev,
 
        mutex_lock(&matrix_dev->lock);
        clear_bit_inv((unsigned long)apqi, matrix_mdev->matrix.aqm);
+       vfio_ap_mdev_update_crycb(matrix_mdev);
        mutex_unlock(&matrix_dev->lock);
 
        return count;
@@ -440,10 +442,6 @@ static ssize_t assign_control_domain_store(struct device 
*dev,
        struct mdev_device *mdev = mdev_from_dev(dev);
        struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
 
-       /* If the guest is running, disallow assignment of control domain */
-       if (matrix_mdev->kvm)
-               return -EBUSY;
-
        ret = kstrtoul(buf, 0, &id);
        if (ret)
                return ret;
@@ -451,13 +449,16 @@ static ssize_t assign_control_domain_store(struct device 
*dev,
        if (id > matrix_mdev->matrix.adm_max)
                return -ENODEV;
 
-       /* Set the bit in the ADM (bitmask) corresponding to the AP control
-        * domain number (id). The bits in the mask, from most significant to
-        * least significant, correspond to IDs 0 up to the one less than the
-        * number of control domains that can be assigned.
+       /*
+        * Set the bits in the ADM (bitmask) corresponding to the AP control
+        * domain numbers in dommask. The bits in the mask, from left to right,
+        * correspond to IDs 0 up to the one less than the number of control
+        * domains that can be assigned.
+        *
         */
        mutex_lock(&matrix_dev->lock);
        set_bit_inv(id, matrix_mdev->matrix.adm);
+       vfio_ap_mdev_update_crycb(matrix_mdev);
        mutex_unlock(&matrix_dev->lock);
 
        return count;
@@ -490,10 +491,6 @@ static ssize_t unassign_control_domain_store(struct device 
*dev,
        struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
        unsigned long max_domid =  matrix_mdev->matrix.adm_max;
 
-       /* If the guest is running, disallow un-assignment of control domain */
-       if (matrix_mdev->kvm)
-               return -EBUSY;
-
        ret = kstrtoul(buf, 0, &domid);
        if (ret)
                return ret;
@@ -502,6 +499,7 @@ static ssize_t unassign_control_domain_store(struct device 
*dev,
 
        mutex_lock(&matrix_dev->lock);
        clear_bit_inv(domid, matrix_mdev->matrix.adm);
+       vfio_ap_mdev_update_crycb(matrix_mdev);
        mutex_unlock(&matrix_dev->lock);
 
        return count;
-- 
2.7.4

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