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Subject[PATCH v2 1/8] s390: vfio-ap: maintain a shadow of the CRYCB in use by a guest
Date
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 | 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
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