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Tony Krowiakborntraeger
Tony Krowiak
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borntraeger
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s390: vfio-ap: implement mediated device open callback
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@linux.ibm.com> Acked-by: Halil Pasic <pasic@linux.ibm.com> Tested-by: Michael Mueller <mimu@linux.ibm.com> Tested-by: Farhan Ali <alifm@linux.ibm.com> Tested-by: Pierre Morel <pmorel@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Message-Id: <20180925231641.4954-12-akrowiak@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
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‎arch/s390/include/asm/kvm_host.h

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -258,6 +258,7 @@ struct kvm_s390_sie_block {
258258
__u64 tecmc; /* 0x00e8 */
259259
__u8 reservedf0[12]; /* 0x00f0 */
260260
#define CRYCB_FORMAT_MASK 0x00000003
261+
#define CRYCB_FORMAT0 0x00000000
261262
#define CRYCB_FORMAT1 0x00000001
262263
#define CRYCB_FORMAT2 0x00000003
263264
__u32 crycbd; /* 0x00fc */

‎drivers/s390/crypto/vfio_ap_ops.c

Lines changed: 161 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -13,6 +13,10 @@
1313
#include <linux/device.h>
1414
#include <linux/list.h>
1515
#include <linux/ctype.h>
16+
#include <linux/bitops.h>
17+
#include <linux/kvm_host.h>
18+
#include <linux/module.h>
19+
#include <asm/kvm.h>
1620
#include <asm/zcrypt.h>
1721

1822
#include "vfio_ap_private.h"
@@ -54,6 +58,9 @@ static int vfio_ap_mdev_remove(struct mdev_device *mdev)
5458
{
5559
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
5660

61+
if (matrix_mdev->kvm)
62+
return -EBUSY;
63+
5764
mutex_lock(&matrix_dev->lock);
5865
list_del(&matrix_mdev->node);
5966
mutex_unlock(&matrix_dev->lock);
@@ -305,6 +312,10 @@ static ssize_t assign_adapter_store(struct device *dev,
305312
struct mdev_device *mdev = mdev_from_dev(dev);
306313
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
307314

315+
/* If the guest is running, disallow assignment of adapter */
316+
if (matrix_mdev->kvm)
317+
return -EBUSY;
318+
308319
ret = kstrtoul(buf, 0, &apid);
309320
if (ret)
310321
return ret;
@@ -367,6 +378,10 @@ static ssize_t unassign_adapter_store(struct device *dev,
367378
struct mdev_device *mdev = mdev_from_dev(dev);
368379
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
369380

381+
/* If the guest is running, disallow un-assignment of adapter */
382+
if (matrix_mdev->kvm)
383+
return -EBUSY;
384+
370385
ret = kstrtoul(buf, 0, &apid);
371386
if (ret)
372387
return ret;
@@ -444,6 +459,10 @@ static ssize_t assign_domain_store(struct device *dev,
444459
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
445460
unsigned long max_apqi = matrix_mdev->matrix.aqm_max;
446461

462+
/* If the guest is running, disallow assignment of domain */
463+
if (matrix_mdev->kvm)
464+
return -EBUSY;
465+
447466
ret = kstrtoul(buf, 0, &apqi);
448467
if (ret)
449468
return ret;
@@ -501,6 +520,10 @@ static ssize_t unassign_domain_store(struct device *dev,
501520
struct mdev_device *mdev = mdev_from_dev(dev);
502521
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
503522

523+
/* If the guest is running, disallow un-assignment of domain */
524+
if (matrix_mdev->kvm)
525+
return -EBUSY;
526+
504527
ret = kstrtoul(buf, 0, &apqi);
505528
if (ret)
506529
return ret;
@@ -541,6 +564,10 @@ static ssize_t assign_control_domain_store(struct device *dev,
541564
struct mdev_device *mdev = mdev_from_dev(dev);
542565
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
543566

567+
/* If the guest is running, disallow assignment of control domain */
568+
if (matrix_mdev->kvm)
569+
return -EBUSY;
570+
544571
ret = kstrtoul(buf, 0, &id);
545572
if (ret)
546573
return ret;
@@ -587,6 +614,10 @@ static ssize_t unassign_control_domain_store(struct device *dev,
587614
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
588615
unsigned long max_domid = matrix_mdev->matrix.adm_max;
589616

617+
/* If the guest is running, disallow un-assignment of control domain */
618+
if (matrix_mdev->kvm)
619+
return -EBUSY;
620+
590621
ret = kstrtoul(buf, 0, &domid);
591622
if (ret)
592623
return ret;
@@ -696,12 +727,142 @@ static const struct attribute_group *vfio_ap_mdev_attr_groups[] = {
696727
NULL
697728
};
698729

730+
static void vfio_ap_mdev_copy_masks(struct ap_matrix_mdev *matrix_mdev)
731+
{
732+
int nbytes;
733+
unsigned long *apm, *aqm, *adm;
734+
struct kvm_s390_crypto_cb *crycb = matrix_mdev->kvm->arch.crypto.crycb;
735+
736+
switch (matrix_mdev->kvm->arch.crypto.crycbd & CRYCB_FORMAT_MASK) {
737+
case CRYCB_FORMAT2:
738+
apm = (unsigned long *)crycb->apcb1.apm;
739+
aqm = (unsigned long *)crycb->apcb1.aqm;
740+
adm = (unsigned long *)crycb->apcb1.adm;
741+
break;
742+
case CRYCB_FORMAT1:
743+
case CRYCB_FORMAT0:
744+
apm = (unsigned long *)crycb->apcb0.apm;
745+
aqm = (unsigned long *)crycb->apcb0.aqm;
746+
adm = (unsigned long *)crycb->apcb0.adm;
747+
break;
748+
default:
749+
/* cannot happen */
750+
return;
751+
}
752+
753+
nbytes = DIV_ROUND_UP(matrix_mdev->matrix.apm_max + 1, BITS_PER_BYTE);
754+
memcpy(apm, matrix_mdev->matrix.apm, nbytes);
755+
nbytes = DIV_ROUND_UP(matrix_mdev->matrix.aqm_max + 1, BITS_PER_BYTE);
756+
memcpy(aqm, matrix_mdev->matrix.aqm, nbytes);
757+
nbytes = DIV_ROUND_UP(matrix_mdev->matrix.adm_max + 1, BITS_PER_BYTE);
758+
memcpy(adm, matrix_mdev->matrix.adm, nbytes);
759+
}
760+
761+
/**
762+
* vfio_ap_mdev_set_kvm
763+
*
764+
* @matrix_mdev: a mediated matrix device
765+
* @kvm: reference to KVM instance
766+
*
767+
* Verifies no other mediated matrix device has @kvm and sets a reference to
768+
* it in @matrix_mdev->kvm.
769+
*
770+
* Return 0 if no other mediated matrix device has a reference to @kvm;
771+
* otherwise, returns an -EPERM.
772+
*/
773+
static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev *matrix_mdev,
774+
struct kvm *kvm)
775+
{
776+
struct ap_matrix_mdev *m;
777+
778+
mutex_lock(&matrix_dev->lock);
779+
780+
list_for_each_entry(m, &matrix_dev->mdev_list, node) {
781+
if ((m != matrix_mdev) && (m->kvm == kvm)) {
782+
mutex_unlock(&matrix_dev->lock);
783+
return -EPERM;
784+
}
785+
}
786+
787+
matrix_mdev->kvm = kvm;
788+
mutex_unlock(&matrix_dev->lock);
789+
790+
return 0;
791+
}
792+
793+
static int vfio_ap_mdev_group_notifier(struct notifier_block *nb,
794+
unsigned long action, void *data)
795+
{
796+
int ret;
797+
struct ap_matrix_mdev *matrix_mdev;
798+
799+
if (action != VFIO_GROUP_NOTIFY_SET_KVM)
800+
return NOTIFY_OK;
801+
802+
matrix_mdev = container_of(nb, struct ap_matrix_mdev, group_notifier);
803+
804+
if (!data) {
805+
matrix_mdev->kvm = NULL;
806+
return NOTIFY_OK;
807+
}
808+
809+
ret = vfio_ap_mdev_set_kvm(matrix_mdev, data);
810+
if (ret)
811+
return NOTIFY_DONE;
812+
813+
/* If there is no CRYCB pointer, then we can't copy the masks */
814+
if (!matrix_mdev->kvm->arch.crypto.crycbd)
815+
return NOTIFY_DONE;
816+
817+
vfio_ap_mdev_copy_masks(matrix_mdev);
818+
819+
return NOTIFY_OK;
820+
}
821+
822+
static int vfio_ap_mdev_open(struct mdev_device *mdev)
823+
{
824+
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
825+
unsigned long events;
826+
int ret;
827+
828+
829+
if (!try_module_get(THIS_MODULE))
830+
return -ENODEV;
831+
832+
matrix_mdev->group_notifier.notifier_call = vfio_ap_mdev_group_notifier;
833+
events = VFIO_GROUP_NOTIFY_SET_KVM;
834+
835+
ret = vfio_register_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
836+
&events, &matrix_mdev->group_notifier);
837+
if (ret) {
838+
module_put(THIS_MODULE);
839+
return ret;
840+
}
841+
842+
return 0;
843+
}
844+
845+
static void vfio_ap_mdev_release(struct mdev_device *mdev)
846+
{
847+
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
848+
849+
if (matrix_mdev->kvm)
850+
kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
851+
852+
vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
853+
&matrix_mdev->group_notifier);
854+
matrix_mdev->kvm = NULL;
855+
module_put(THIS_MODULE);
856+
}
857+
699858
static const struct mdev_parent_ops vfio_ap_matrix_ops = {
700859
.owner = THIS_MODULE,
701860
.supported_type_groups = vfio_ap_mdev_type_groups,
702861
.mdev_attr_groups = vfio_ap_mdev_attr_groups,
703862
.create = vfio_ap_mdev_create,
704863
.remove = vfio_ap_mdev_remove,
864+
.open = vfio_ap_mdev_open,
865+
.release = vfio_ap_mdev_release,
705866
};
706867

707868
int vfio_ap_mdev_register(void)

‎drivers/s390/crypto/vfio_ap_private.h

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -71,10 +71,15 @@ struct ap_matrix {
7171
* @list: allows the ap_matrix_mdev struct to be added to a list
7272
* @matrix: the adapters, usage domains and control domains assigned to the
7373
* mediated matrix device.
74+
* @group_notifier: notifier block used for specifying callback function for
75+
* handling the VFIO_GROUP_NOTIFY_SET_KVM event
76+
* @kvm: the struct holding guest's state
7477
*/
7578
struct ap_matrix_mdev {
7679
struct list_head node;
7780
struct ap_matrix matrix;
81+
struct notifier_block group_notifier;
82+
struct kvm *kvm;
7883
};
7984

8085
extern int vfio_ap_mdev_register(void);

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