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Commit 258287c9 authored by Tony Krowiak's avatar Tony Krowiak Committed by Christian Borntraeger
Browse files

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: default avatarTony Krowiak <akrowiak@linux.ibm.com>
Acked-by: default avatarHalil Pasic <pasic@linux.ibm.com>
Tested-by: default avatarMichael Mueller <mimu@linux.ibm.com>
Tested-by: default avatarFarhan Ali <alifm@linux.ibm.com>
Tested-by: default avatarPierre Morel <pmorel@linux.ibm.com>
Acked-by: default avatarPierre Morel <pmorel@linux.ibm.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Message-Id: <20180925231641.4954-12-akrowiak@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 42104598

arch/s390/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -258,6 +258,7 @@ struct kvm_s390_sie_block { 
	__u64	tecmc;			/* 0x00e8 */

	__u8	reservedf0[12];		/* 0x00f0 */

#define CRYCB_FORMAT_MASK 0x00000003

#define CRYCB_FORMAT0 0x00000000

#define CRYCB_FORMAT1 0x00000001

#define CRYCB_FORMAT2 0x00000003

	__u32	crycbd;			/* 0x00fc */

drivers/s390/crypto/vfio_ap_ops.c

+161 −0
Original line number Diff line number Diff line
@@ -13,6 +13,10 @@ 
#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 <asm/zcrypt.h>



#include "vfio_ap_private.h"
@@ -54,6 +58,9 @@ static int vfio_ap_mdev_remove(struct mdev_device *mdev) 
{

	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);



	if (matrix_mdev->kvm)

		return -EBUSY;



	mutex_lock(&matrix_dev->lock);

	list_del(&matrix_mdev->node);

	mutex_unlock(&matrix_dev->lock);
@@ -305,6 +312,10 @@ static ssize_t assign_adapter_store(struct device *dev, 
	struct mdev_device *mdev = mdev_from_dev(dev);

	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);



	/* If the guest is running, disallow assignment of adapter */

	if (matrix_mdev->kvm)

		return -EBUSY;



	ret = kstrtoul(buf, 0, &apid);

	if (ret)

		return ret;
@@ -367,6 +378,10 @@ static ssize_t unassign_adapter_store(struct device *dev, 
	struct mdev_device *mdev = mdev_from_dev(dev);

	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);



	/* If the guest is running, disallow un-assignment of adapter */

	if (matrix_mdev->kvm)

		return -EBUSY;



	ret = kstrtoul(buf, 0, &apid);

	if (ret)

		return ret;
@@ -444,6 +459,10 @@ static ssize_t assign_domain_store(struct device *dev, 
	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

	unsigned long max_apqi = matrix_mdev->matrix.aqm_max;



	/* If the guest is running, disallow assignment of domain */

	if (matrix_mdev->kvm)

		return -EBUSY;



	ret = kstrtoul(buf, 0, &apqi);

	if (ret)

		return ret;
@@ -501,6 +520,10 @@ static ssize_t unassign_domain_store(struct device *dev, 
	struct mdev_device *mdev = mdev_from_dev(dev);

	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);



	/* If the guest is running, disallow un-assignment of domain */

	if (matrix_mdev->kvm)

		return -EBUSY;



	ret = kstrtoul(buf, 0, &apqi);

	if (ret)

		return ret;
@@ -541,6 +564,10 @@ static ssize_t assign_control_domain_store(struct device *dev, 
	struct mdev_device *mdev = mdev_from_dev(dev);

	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);



	/* If the guest is running, disallow assignment of control domain */

	if (matrix_mdev->kvm)

		return -EBUSY;



	ret = kstrtoul(buf, 0, &id);

	if (ret)

		return ret;
@@ -587,6 +614,10 @@ static ssize_t unassign_control_domain_store(struct device *dev, 
	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

	unsigned long max_domid =  matrix_mdev->matrix.adm_max;



	/* If the guest is running, disallow un-assignment of control domain */

	if (matrix_mdev->kvm)

		return -EBUSY;



	ret = kstrtoul(buf, 0, &domid);

	if (ret)

		return ret;
@@ -696,12 +727,142 @@ static const struct attribute_group *vfio_ap_mdev_attr_groups[] = { 
	NULL

};



static void vfio_ap_mdev_copy_masks(struct ap_matrix_mdev *matrix_mdev)

{

	int nbytes;

	unsigned long *apm, *aqm, *adm;

	struct kvm_s390_crypto_cb *crycb = matrix_mdev->kvm->arch.crypto.crycb;



	switch (matrix_mdev->kvm->arch.crypto.crycbd & CRYCB_FORMAT_MASK) {

	case CRYCB_FORMAT2:

		apm = (unsigned long *)crycb->apcb1.apm;

		aqm = (unsigned long *)crycb->apcb1.aqm;

		adm = (unsigned long *)crycb->apcb1.adm;

		break;

	case CRYCB_FORMAT1:

	case CRYCB_FORMAT0:

		apm = (unsigned long *)crycb->apcb0.apm;

		aqm = (unsigned long *)crycb->apcb0.aqm;

		adm = (unsigned long *)crycb->apcb0.adm;

		break;

	default:

		/* cannot happen */

		return;

	}



	nbytes = DIV_ROUND_UP(matrix_mdev->matrix.apm_max + 1, BITS_PER_BYTE);

	memcpy(apm, matrix_mdev->matrix.apm, nbytes);

	nbytes = DIV_ROUND_UP(matrix_mdev->matrix.aqm_max + 1, BITS_PER_BYTE);

	memcpy(aqm, matrix_mdev->matrix.aqm, nbytes);

	nbytes = DIV_ROUND_UP(matrix_mdev->matrix.adm_max + 1, BITS_PER_BYTE);

	memcpy(adm, matrix_mdev->matrix.adm, nbytes);

}



/**

 * vfio_ap_mdev_set_kvm

 *

 * @matrix_mdev: a mediated matrix device

 * @kvm: reference to KVM instance

 *

 * Verifies no other mediated matrix device has @kvm and sets a reference to

 * it in @matrix_mdev->kvm.

 *

 * Return 0 if no other mediated matrix device has a reference to @kvm;

 * otherwise, returns an -EPERM.

 */

static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev *matrix_mdev,

				struct kvm *kvm)

{

	struct ap_matrix_mdev *m;



	mutex_lock(&matrix_dev->lock);



	list_for_each_entry(m, &matrix_dev->mdev_list, node) {

		if ((m != matrix_mdev) && (m->kvm == kvm)) {

			mutex_unlock(&matrix_dev->lock);

			return -EPERM;

		}

	}



	matrix_mdev->kvm = kvm;

	mutex_unlock(&matrix_dev->lock);



	return 0;

}



static int vfio_ap_mdev_group_notifier(struct notifier_block *nb,

				       unsigned long action, void *data)

{

	int ret;

	struct ap_matrix_mdev *matrix_mdev;



	if (action != VFIO_GROUP_NOTIFY_SET_KVM)

		return NOTIFY_OK;



	matrix_mdev = container_of(nb, struct ap_matrix_mdev, group_notifier);



	if (!data) {

		matrix_mdev->kvm = NULL;

		return NOTIFY_OK;

	}



	ret = vfio_ap_mdev_set_kvm(matrix_mdev, data);

	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)

		return NOTIFY_DONE;



	vfio_ap_mdev_copy_masks(matrix_mdev);



	return NOTIFY_OK;

}



static int vfio_ap_mdev_open(struct mdev_device *mdev)

{

	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

	unsigned long events;

	int ret;





	if (!try_module_get(THIS_MODULE))

		return -ENODEV;



	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) {

		module_put(THIS_MODULE);

		return ret;

	}



	return 0;

}



static void vfio_ap_mdev_release(struct mdev_device *mdev)

{

	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);



	if (matrix_mdev->kvm)

		kvm_arch_crypto_clear_masks(matrix_mdev->kvm);



	vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,

				 &matrix_mdev->group_notifier);

	matrix_mdev->kvm = NULL;

	module_put(THIS_MODULE);

}



static const struct mdev_parent_ops vfio_ap_matrix_ops = {

	.owner			= THIS_MODULE,

	.supported_type_groups	= vfio_ap_mdev_type_groups,

	.mdev_attr_groups	= vfio_ap_mdev_attr_groups,

	.create			= vfio_ap_mdev_create,

	.remove			= vfio_ap_mdev_remove,

	.open			= vfio_ap_mdev_open,

	.release		= vfio_ap_mdev_release,

};



int vfio_ap_mdev_register(void)

drivers/s390/crypto/vfio_ap_private.h

+5 −0
Original line number Diff line number Diff line
@@ -71,10 +71,15 @@ 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.

 * @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

 */

struct ap_matrix_mdev {

	struct list_head node;

	struct ap_matrix matrix;

	struct notifier_block group_notifier;

	struct kvm *kvm;

};



extern int vfio_ap_mdev_register(void);