[PATCH v8 06/16] s390/vfio-ap: introduce shadow APCB

Tony Krowiak
2020-06-05T21:40:19Z

The APCB is a field within the CRYCB that provides the AP configuration
to a KVM guest. Let's introduce a shadow copy of the KVM guest's APCB and
maintain it for the lifespan of the guest.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_ops.c | 33 +++++++++++++++++++++++----
drivers/s390/crypto/vfio_ap_private.h | 2 ++
2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 2eebb2b6d2d4..b5ed36e2c948 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -292,14 +292,35 @@ static int handle_pqap(struct kvm_vcpu *vcpu)
return 0;
}

+static void vfio_ap_matrix_clear_masks(struct ap_matrix *matrix)
+{
+ bitmap_clear(matrix->apm, 0, AP_DEVICES);
+ bitmap_clear(matrix->aqm, 0, AP_DOMAINS);
+ bitmap_clear(matrix->adm, 0, AP_DOMAINS);
+}
+
static void vfio_ap_matrix_init(struct ap_config_info *info,
struct ap_matrix *matrix)
{
+ vfio_ap_matrix_clear_masks(matrix);
matrix->apm_max = info->apxa ? info->Na : 63;
matrix->aqm_max = info->apxa ? info->Nd : 15;
matrix->adm_max = info->apxa ? info->Nd : 15;
}

+static bool vfio_ap_mdev_has_crycb(struct ap_matrix_mdev *matrix_mdev)
+{
+ return (matrix_mdev->kvm && matrix_mdev->kvm->arch.crypto.crycbd);
+}
+
+static void vfio_ap_mdev_commit_crycb(struct ap_matrix_mdev *matrix_mdev)
+{
+ kvm_arch_crypto_set_masks(matrix_mdev->kvm,
+ matrix_mdev->shadow_apcb.apm,
+ matrix_mdev->shadow_apcb.aqm,
+ matrix_mdev->shadow_apcb.adm);
+}
+
static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
{
struct ap_matrix_mdev *matrix_mdev;
@@ -315,6 +336,7 @@ static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)

matrix_mdev->mdev = mdev;
vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix);
+ vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->shadow_apcb);
mdev_set_drvdata(mdev, matrix_mdev);
matrix_mdev->pqap_hook.hook = handle_pqap;
matrix_mdev->pqap_hook.owner = THIS_MODULE;
@@ -1168,13 +1190,12 @@ 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_has_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);
+ memcpy(&matrix_mdev->shadow_apcb, &matrix_mdev->matrix,
+ sizeof(matrix_mdev->shadow_apcb));
+ vfio_ap_mdev_commit_crycb(matrix_mdev);

return NOTIFY_OK;
}
@@ -1289,6 +1310,8 @@ static void vfio_ap_mdev_release(struct mdev_device *mdev)
kvm_put_kvm(matrix_mdev->kvm);
matrix_mdev->kvm = NULL;
}
+
+ vfio_ap_matrix_clear_masks(&matrix_mdev->shadow_apcb);
mutex_unlock(&matrix_dev->lock);

vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index ad2d5b6a2851..8e24a073166b 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -75,6 +75,7 @@ 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_apcb: the shadow copy of the APCB field of the KVM guest's CRYCB
* @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
@@ -82,6 +83,7 @@ struct ap_matrix {
struct ap_matrix_mdev {
struct list_head node;
struct ap_matrix matrix;
+ struct ap_matrix shadow_apcb;
struct notifier_block group_notifier;
struct notifier_block iommu_notifier;
struct kvm *kvm;
--
2.21.1