[PATCH v4 6/7] s390: ap: Cleanup on removing the AP device

Pierre Morel
2019-02-22T15:34:29Z

When the device is remove, we must make sure to
clear the interruption and reset the AP device.

We also need to clear the CRYCB of the guest.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_drv.c | 35 +++++++++++++++++++++++++++++++++++
drivers/s390/crypto/vfio_ap_ops.c | 3 ++-
drivers/s390/crypto/vfio_ap_private.h | 3 +++
3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index eca0ffc..e5d91ff 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -5,6 +5,7 @@
* Copyright IBM Corp. 2018
*
* Author(s): Tony Krowiak <akrowiak@linux.ibm.com>
+ * Pierre Morel <pmorel@linux.ibm.com>
*/

#include <linux/module.h>
@@ -12,6 +13,8 @@
#include <linux/slab.h>
#include <linux/string.h>
#include <asm/facility.h>
+#include <linux/bitops.h>
+#include <linux/kvm_host.h>
#include "vfio_ap_private.h"

#define VFIO_AP_ROOT_NAME "vfio_ap"
@@ -61,6 +64,33 @@ static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
}

/**
+ * vfio_ap_update_crycb
+ * @q: A pointer to the queue being removed
+ *
+ * We clear the APID of the queue, making this queue unusable for the guest.
+ * After this function we can reset the queue without to fear a race with
+ * the guest to access the queue again.
+ * We do not fear race with the host as we still get the device.
+ */
+static void vfio_ap_update_crycb(struct vfio_ap_queue *q)
+{
+ struct ap_matrix_mdev *matrix_mdev = q->matrix_mdev;
+
+ if (!matrix_mdev)
+ return;
+
+ clear_bit_inv(AP_QID_CARD(q->apqn), matrix_mdev->matrix.apm);
+
+ if (!matrix_mdev->kvm)
+ return;
+
+ kvm_arch_crypto_set_masks(matrix_mdev->kvm,
+ matrix_mdev->matrix.apm,
+ matrix_mdev->matrix.aqm,
+ matrix_mdev->matrix.adm);
+}
+
+/**
* vfio_ap_queue_dev_remove:
*
* Free the associated vfio_ap_queue structure
@@ -70,6 +100,11 @@ static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
struct vfio_ap_queue *q;

q = dev_get_drvdata(&apdev->device);
+ if (!q)
+ return;
+
+ vfio_ap_update_crycb(q);
+ vfio_ap_mdev_reset_queue(q);
list_del(&q->list);
kfree(q);
}
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 0196065..5b9bb33 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -59,6 +59,7 @@ int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q)
if (retry <= 0)
pr_warn("%s: queue 0x%04x not empty\n",
__func__, q->apqn);
+ vfio_ap_free_irq(q);
return 0;
case AP_RESPONSE_RESET_IN_PROGRESS:
case AP_RESPONSE_BUSY:
@@ -83,7 +84,7 @@ int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q)
* Unregister the ISC from the GIB alert
* Clear the vfio_ap_queue intern fields
*/
-static void vfio_ap_free_irq(struct vfio_ap_queue *q)
+void vfio_ap_free_irq(struct vfio_ap_queue *q)
{
if (!q)
return;
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index e2fd2c0..cc18215 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -4,6 +4,7 @@
*
* Author(s): Tony Krowiak <akrowiak@linux.ibm.com>
* Halil Pasic <pasic@linux.ibm.com>
+ * Pierre Morel <pmorel@linux.ibm.com>
*
* Copyright IBM Corp. 2018
*/
@@ -98,4 +99,6 @@ struct vfio_ap_queue {
int apqn;
unsigned char isc;
};
+void vfio_ap_free_irq(struct vfio_ap_queue *q);
+int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q);
#endif /* _VFIO_AP_PRIVATE_H_ */
--
2.7.4