Implements the open callback on the mediated matrix device.
The function registers a group notifier to receive notification
of the VFIO_GROUP_NOTIFY_SET_KVM event. When notified,
the vfio_ap device driver will get access to the guest's
kvm structure. The open callback must ensure that only one
mediated device shall be opened per guest.
Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
---
drivers/s390/crypto/vfio_ap_ops.c | 128 +++++++++++++++++++++++++++++++++
drivers/s390/crypto/vfio_ap_private.h | 2 +
2 files changed, 130 insertions(+), 0 deletions(-)
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index bc7398d..58be495 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -11,6 +11,10 @@
#include <linux/device.h>
#include <linux/list.h>
#include <linux/ctype.h>
+#include <linux/bitops.h>
+#include <linux/kvm_host.h>
+#include <linux/module.h>
+#include <asm/kvm.h>
#include "vfio_ap_private.h"
@@ -748,12 +752,136 @@ static ssize_t matrix_show(struct device *dev, struct device_attribute *attr,
NULL
};
+/**
+ * Verify that the AP instructions are available on the guest and are to be
+ * interpreted by the firmware. The former is indicated via the
+ * KVM_S390_VM_CPU_FEAT_AP CPU model feature and the latter by apie crypto
+ * flag.
+ */
+static int kvm_ap_validate_crypto_setup(struct kvm *kvm)
+{
+ if (test_bit_inv(KVM_S390_VM_CPU_FEAT_AP, kvm->arch.cpu_feat) &&
+ kvm->arch.crypto.apie)
+ return 0;
+
+ pr_err("%s: interpretation of AP instructions not available",
+ VFIO_AP_MODULE_NAME);
+
+ return -EOPNOTSUPP;
+}
+
+static int vfio_ap_mdev_group_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct ap_matrix_mdev *matrix_mdev;
+
+ if (action == VFIO_GROUP_NOTIFY_SET_KVM) {
+ matrix_mdev = container_of(nb, struct ap_matrix_mdev,
+ group_notifier);
+ matrix_mdev->kvm = data;
+ }
+
+ return NOTIFY_OK;
+}
+
+
+static int vfio_ap_mdev_open(struct mdev_device *mdev)
+{
+ struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+ struct ap_matrix_dev *matrix_dev =
+ to_ap_matrix_dev(mdev_parent_dev(mdev));
+ unsigned long events;
+ int ret;
+
+ if (!try_module_get(THIS_MODULE))
+ return -ENODEV;
+
+ ret = vfio_ap_verify_queues_reserved(matrix_dev, matrix_mdev->name,
+ &matrix_mdev->matrix);
+ if (ret)
+ goto out_err;
+
+ matrix_mdev->group_notifier.notifier_call = vfio_ap_mdev_group_notifier;
+ events = VFIO_GROUP_NOTIFY_SET_KVM;
+
+ ret = vfio_register_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
+ &events, &matrix_mdev->group_notifier);
+ if (ret)
+ goto out_err;
+
+ ret = kvm_ap_validate_crypto_setup(matrix_mdev->kvm);
+ if (ret)
+ goto out_kvm_err;
+
+ ret = vfio_ap_mdev_open_once(matrix_mdev);
+ if (ret)
+ goto out_kvm_err;
+
+ return 0;
+
+out_kvm_err:
+ vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
+ &matrix_mdev->group_notifier);
+ matrix_mdev->kvm = NULL;
+out_err:
+ module_put(THIS_MODULE);
+
+ return ret;
+}
+