[qemu-s390x] [RFC 14/19] KVM: s390: Connect the AP mediated matrix device to KVM

[Tony Krowiak]

Registers a group notifier during the open of the mediated
device to get information on KVM presence through the
VFIO_GROUP_NOTIFY_SET_KVM event.

When notified, save the pointer to KVM inside mediated matrix device
structure.

Signed-off-by: Tony Krowiak <address@hidden>
---
 drivers/s390/crypto/vfio_ap_matrix_ops.c |   43 ++++++++++++++++++++++++++++++
 1 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_matrix_ops.c 
b/drivers/s390/crypto/vfio_ap_matrix_ops.c
index 10a006c..fd36074 100644
--- a/drivers/s390/crypto/vfio_ap_matrix_ops.c
+++ b/drivers/s390/crypto/vfio_ap_matrix_ops.c
@@ -12,6 +12,9 @@
 #include <linux/device.h>
 #include <linux/list.h>
 #include <linux/ctype.h>
+#include <linux/kvm_host.h>
+#include <linux/eventfd.h>
+#include <linux/notifier.h>
 
 #include "vfio_ap_matrix_private.h"
 
@@ -24,6 +27,8 @@ struct ap_matrix_mdev {
        struct mdev_device *mdev;
        struct list_head node;
        struct ap_config_masks masks;
+       struct notifier_block group_notifier;
+       struct kvm *kvm;
 };
 
 struct ap_matrix       *matrix;
@@ -97,6 +102,41 @@ static int ap_matrix_mdev_remove(struct mdev_device *mdev)
        return 0;
 }
 
+static int ap_matrix_mdev_group_notifier(struct notifier_block *nb,
+                                        unsigned long action, void *data)
+{
+       struct ap_matrix_mdev *matrix_mdev;
+
+       matrix_mdev = container_of(nb, struct ap_matrix_mdev, group_notifier);
+
+       if (action == VFIO_GROUP_NOTIFY_SET_KVM)
+               matrix_mdev->kvm = data;
+
+       return NOTIFY_OK;
+}
+
+static int ap_matrix_mdev_open(struct mdev_device *mdev)
+{
+       struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+       unsigned long events;
+       int ret;
+
+       matrix_mdev->group_notifier.notifier_call =
+               ap_matrix_mdev_group_notifier;
+       events = VFIO_GROUP_NOTIFY_SET_KVM;
+       ret = vfio_register_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
+                                    &events, &matrix_mdev->group_notifier);
+       return ret;
+}
+
+static void ap_matrix_mdev_release(struct mdev_device *mdev)
+{
+       struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+
+       vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
+                                &matrix_mdev->group_notifier);
+}
+
 static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)
 {
        return sprintf(buf, "%s\n", AP_MATRIX_MDEV_NAME_HWVIRT);
@@ -609,6 +649,9 @@ static DEVICE_ATTR(control_domains, 0644, 
ap_matrix_control_domains_show,
        .mdev_attr_groups       = ap_matrix_mdev_attr_groups,
        .create                 = ap_matrix_mdev_create,
        .remove                 = ap_matrix_mdev_remove,
+       .open                   = ap_matrix_mdev_open,
+       .release                = ap_matrix_mdev_release,
+
 };
 
 int ap_matrix_mdev_register(struct ap_matrix *ap_matrix)
-- 
1.7.1