ASR_BASE

Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/drivers/s390/crypto/vfio_ap_ops.c b/marvell/linux/drivers/s390/crypto/vfio_ap_ops.c
new file mode 100644
index 0000000..1ec0114
--- /dev/null
+++ b/marvell/linux/drivers/s390/crypto/vfio_ap_ops.c
@@ -0,0 +1,1328 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Adjunct processor matrix VFIO device driver callbacks.
+ *
+ * Copyright IBM Corp. 2018
+ *
+ * Author(s): Tony Krowiak <akrowiak@linux.ibm.com>
+ *	      Halil Pasic <pasic@linux.ibm.com>
+ *	      Pierre Morel <pmorel@linux.ibm.com>
+ */
+#include <linux/string.h>
+#include <linux/vfio.h>
+#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"
+
+#define VFIO_AP_MDEV_TYPE_HWVIRT "passthrough"
+#define VFIO_AP_MDEV_NAME_HWVIRT "VFIO AP Passthrough Device"
+
+static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);
+static struct vfio_ap_queue *vfio_ap_find_queue(int apqn);
+
+static int match_apqn(struct device *dev, const void *data)
+{
+	struct vfio_ap_queue *q = dev_get_drvdata(dev);
+
+	return (q->apqn == *(int *)(data)) ? 1 : 0;
+}
+
+/**
+ * vfio_ap_get_queue: Retrieve a queue with a specific APQN from a list
+ * @matrix_mdev: the associated mediated matrix
+ * @apqn: The queue APQN
+ *
+ * Retrieve a queue with a specific APQN from the list of the
+ * devices of the vfio_ap_drv.
+ * Verify that the APID and the APQI are set in the matrix.
+ *
+ * Returns the pointer to the associated vfio_ap_queue
+ */
+static struct vfio_ap_queue *vfio_ap_get_queue(
+					struct ap_matrix_mdev *matrix_mdev,
+					int apqn)
+{
+	struct vfio_ap_queue *q;
+
+	if (!test_bit_inv(AP_QID_CARD(apqn), matrix_mdev->matrix.apm))
+		return NULL;
+	if (!test_bit_inv(AP_QID_QUEUE(apqn), matrix_mdev->matrix.aqm))
+		return NULL;
+
+	q = vfio_ap_find_queue(apqn);
+	if (q)
+		q->matrix_mdev = matrix_mdev;
+
+	return q;
+}
+
+/**
+ * vfio_ap_wait_for_irqclear
+ * @apqn: The AP Queue number
+ *
+ * Checks the IRQ bit for the status of this APQN using ap_tapq.
+ * Returns if the ap_tapq function succeeded and the bit is clear.
+ * Returns if ap_tapq function failed with invalid, deconfigured or
+ * checkstopped AP.
+ * Otherwise retries up to 5 times after waiting 20ms.
+ *
+ */
+static void vfio_ap_wait_for_irqclear(int apqn)
+{
+	struct ap_queue_status status;
+	int retry = 5;
+
+	do {
+		status = ap_tapq(apqn, NULL);
+		switch (status.response_code) {
+		case AP_RESPONSE_NORMAL:
+		case AP_RESPONSE_RESET_IN_PROGRESS:
+			if (!status.irq_enabled)
+				return;
+			/* Fall through */
+		case AP_RESPONSE_BUSY:
+			msleep(20);
+			break;
+		case AP_RESPONSE_Q_NOT_AVAIL:
+		case AP_RESPONSE_DECONFIGURED:
+		case AP_RESPONSE_CHECKSTOPPED:
+		default:
+			WARN_ONCE(1, "%s: tapq rc %02x: %04x\n", __func__,
+				  status.response_code, apqn);
+			return;
+		}
+	} while (--retry);
+
+	WARN_ONCE(1, "%s: tapq rc %02x: %04x could not clear IR bit\n",
+		  __func__, status.response_code, apqn);
+}
+
+/**
+ * vfio_ap_free_aqic_resources
+ * @q: The vfio_ap_queue
+ *
+ * Unregisters the ISC in the GIB when the saved ISC not invalid.
+ * Unpin the guest's page holding the NIB when it exist.
+ * Reset the saved_pfn and saved_isc to invalid values.
+ *
+ */
+static void vfio_ap_free_aqic_resources(struct vfio_ap_queue *q)
+{
+	if (!q)
+		return;
+	if (q->saved_isc != VFIO_AP_ISC_INVALID &&
+	    !WARN_ON(!(q->matrix_mdev && q->matrix_mdev->kvm))) {
+		kvm_s390_gisc_unregister(q->matrix_mdev->kvm, q->saved_isc);
+		q->saved_isc = VFIO_AP_ISC_INVALID;
+	}
+	if (q->saved_pfn && !WARN_ON(!q->matrix_mdev)) {
+		vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev),
+				 &q->saved_pfn, 1);
+		q->saved_pfn = 0;
+	}
+}
+
+/**
+ * vfio_ap_irq_disable
+ * @q: The vfio_ap_queue
+ *
+ * Uses ap_aqic to disable the interruption and in case of success, reset
+ * in progress or IRQ disable command already proceeded: calls
+ * vfio_ap_wait_for_irqclear() to check for the IRQ bit to be clear
+ * and calls vfio_ap_free_aqic_resources() to free the resources associated
+ * with the AP interrupt handling.
+ *
+ * In the case the AP is busy, or a reset is in progress,
+ * retries after 20ms, up to 5 times.
+ *
+ * Returns if ap_aqic function failed with invalid, deconfigured or
+ * checkstopped AP.
+ */
+static struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q)
+{
+	struct ap_qirq_ctrl aqic_gisa = {};
+	struct ap_queue_status status;
+	int retries = 5;
+
+	do {
+		status = ap_aqic(q->apqn, aqic_gisa, NULL);
+		switch (status.response_code) {
+		case AP_RESPONSE_OTHERWISE_CHANGED:
+		case AP_RESPONSE_NORMAL:
+			vfio_ap_wait_for_irqclear(q->apqn);
+			goto end_free;
+		case AP_RESPONSE_RESET_IN_PROGRESS:
+		case AP_RESPONSE_BUSY:
+			msleep(20);
+			break;
+		case AP_RESPONSE_Q_NOT_AVAIL:
+		case AP_RESPONSE_DECONFIGURED:
+		case AP_RESPONSE_CHECKSTOPPED:
+		case AP_RESPONSE_INVALID_ADDRESS:
+		default:
+			/* All cases in default means AP not operational */
+			WARN_ONCE(1, "%s: ap_aqic status %d\n", __func__,
+				  status.response_code);
+			goto end_free;
+		}
+	} while (retries--);
+
+	WARN_ONCE(1, "%s: ap_aqic status %d\n", __func__,
+		  status.response_code);
+end_free:
+	vfio_ap_free_aqic_resources(q);
+	q->matrix_mdev = NULL;
+	return status;
+}
+
+/**
+ * vfio_ap_setirq: Enable Interruption for a APQN
+ *
+ * @dev: the device associated with the ap_queue
+ * @q:	 the vfio_ap_queue holding AQIC parameters
+ *
+ * Pin the NIB saved in *q
+ * Register the guest ISC to GIB interface and retrieve the
+ * host ISC to issue the host side PQAP/AQIC
+ *
+ * Response.status may be set to AP_RESPONSE_INVALID_ADDRESS in case the
+ * vfio_pin_pages failed.
+ *
+ * Otherwise return the ap_queue_status returned by the ap_aqic(),
+ * all retry handling will be done by the guest.
+ */
+static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q,
+						 int isc,
+						 unsigned long nib)
+{
+	struct ap_qirq_ctrl aqic_gisa = {};
+	struct ap_queue_status status = {};
+	struct kvm_s390_gisa *gisa;
+	struct kvm *kvm;
+	unsigned long h_nib, g_pfn, h_pfn;
+	int ret;
+
+	g_pfn = nib >> PAGE_SHIFT;
+	ret = vfio_pin_pages(mdev_dev(q->matrix_mdev->mdev), &g_pfn, 1,
+			     IOMMU_READ | IOMMU_WRITE, &h_pfn);
+	switch (ret) {
+	case 1:
+		break;
+	default:
+		status.response_code = AP_RESPONSE_INVALID_ADDRESS;
+		return status;
+	}
+
+	kvm = q->matrix_mdev->kvm;
+	gisa = kvm->arch.gisa_int.origin;
+
+	h_nib = (h_pfn << PAGE_SHIFT) | (nib & ~PAGE_MASK);
+	aqic_gisa.gisc = isc;
+	aqic_gisa.isc = kvm_s390_gisc_register(kvm, isc);
+	aqic_gisa.ir = 1;
+	aqic_gisa.gisa = (uint64_t)gisa >> 4;
+
+	status = ap_aqic(q->apqn, aqic_gisa, (void *)h_nib);
+	switch (status.response_code) {
+	case AP_RESPONSE_NORMAL:
+		/* See if we did clear older IRQ configuration */
+		vfio_ap_free_aqic_resources(q);
+		q->saved_pfn = g_pfn;
+		q->saved_isc = isc;
+		break;
+	case AP_RESPONSE_OTHERWISE_CHANGED:
+		/* We could not modify IRQ setings: clear new configuration */
+		vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev), &g_pfn, 1);
+		kvm_s390_gisc_unregister(kvm, isc);
+		break;
+	default:
+		pr_warn("%s: apqn %04x: response: %02x\n", __func__, q->apqn,
+			status.response_code);
+		vfio_ap_irq_disable(q);
+		break;
+	}
+
+	return status;
+}
+
+/**
+ * handle_pqap: PQAP instruction callback
+ *
+ * @vcpu: The vcpu on which we received the PQAP instruction
+ *
+ * Get the general register contents to initialize internal variables.
+ * REG[0]: APQN
+ * REG[1]: IR and ISC
+ * REG[2]: NIB
+ *
+ * Response.status may be set to following Response Code:
+ * - AP_RESPONSE_Q_NOT_AVAIL: if the queue is not available
+ * - AP_RESPONSE_DECONFIGURED: if the queue is not configured
+ * - AP_RESPONSE_NORMAL (0) : in case of successs
+ *   Check vfio_ap_setirq() and vfio_ap_clrirq() for other possible RC.
+ * We take the matrix_dev lock to ensure serialization on queues and
+ * mediated device access.
+ *
+ * Return 0 if we could handle the request inside KVM.
+ * otherwise, returns -EOPNOTSUPP to let QEMU handle the fault.
+ */
+static int handle_pqap(struct kvm_vcpu *vcpu)
+{
+	uint64_t status;
+	uint16_t apqn;
+	struct vfio_ap_queue *q;
+	struct ap_queue_status qstatus = {
+			       .response_code = AP_RESPONSE_Q_NOT_AVAIL, };
+	struct ap_matrix_mdev *matrix_mdev;
+
+	/* If we do not use the AIV facility just go to userland */
+	if (!(vcpu->arch.sie_block->eca & ECA_AIV))
+		return -EOPNOTSUPP;
+
+	apqn = vcpu->run->s.regs.gprs[0] & 0xffff;
+	mutex_lock(&matrix_dev->lock);
+
+	if (!vcpu->kvm->arch.crypto.pqap_hook)
+		goto out_unlock;
+	matrix_mdev = container_of(vcpu->kvm->arch.crypto.pqap_hook,
+				   struct ap_matrix_mdev, pqap_hook);
+
+	q = vfio_ap_get_queue(matrix_mdev, apqn);
+	if (!q)
+		goto out_unlock;
+
+	status = vcpu->run->s.regs.gprs[1];
+
+	/* If IR bit(16) is set we enable the interrupt */
+	if ((status >> (63 - 16)) & 0x01)
+		qstatus = vfio_ap_irq_enable(q, status & 0x07,
+					     vcpu->run->s.regs.gprs[2]);
+	else
+		qstatus = vfio_ap_irq_disable(q);
+
+out_unlock:
+	memcpy(&vcpu->run->s.regs.gprs[1], &qstatus, sizeof(qstatus));
+	vcpu->run->s.regs.gprs[1] >>= 32;
+	mutex_unlock(&matrix_dev->lock);
+	return 0;
+}
+
+static void vfio_ap_matrix_init(struct ap_config_info *info,
+				struct ap_matrix *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 int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
+{
+	struct ap_matrix_mdev *matrix_mdev;
+
+	if ((atomic_dec_if_positive(&matrix_dev->available_instances) < 0))
+		return -EPERM;
+
+	matrix_mdev = kzalloc(sizeof(*matrix_mdev), GFP_KERNEL);
+	if (!matrix_mdev) {
+		atomic_inc(&matrix_dev->available_instances);
+		return -ENOMEM;
+	}
+
+	matrix_mdev->mdev = mdev;
+	vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix);
+	mdev_set_drvdata(mdev, matrix_mdev);
+	matrix_mdev->pqap_hook.hook = handle_pqap;
+	matrix_mdev->pqap_hook.owner = THIS_MODULE;
+	mutex_lock(&matrix_dev->lock);
+	list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
+	mutex_unlock(&matrix_dev->lock);
+
+	return 0;
+}
+
+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);
+	vfio_ap_mdev_reset_queues(mdev);
+	list_del(&matrix_mdev->node);
+	mutex_unlock(&matrix_dev->lock);
+
+	kfree(matrix_mdev);
+	mdev_set_drvdata(mdev, NULL);
+	atomic_inc(&matrix_dev->available_instances);
+
+	return 0;
+}
+
+static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)
+{
+	return sprintf(buf, "%s\n", VFIO_AP_MDEV_NAME_HWVIRT);
+}
+
+static MDEV_TYPE_ATTR_RO(name);
+
+static ssize_t available_instances_show(struct kobject *kobj,
+					struct device *dev, char *buf)
+{
+	return sprintf(buf, "%d\n",
+		       atomic_read(&matrix_dev->available_instances));
+}
+
+static MDEV_TYPE_ATTR_RO(available_instances);
+
+static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
+			       char *buf)
+{
+	return sprintf(buf, "%s\n", VFIO_DEVICE_API_AP_STRING);
+}
+
+static MDEV_TYPE_ATTR_RO(device_api);
+
+static struct attribute *vfio_ap_mdev_type_attrs[] = {
+	&mdev_type_attr_name.attr,
+	&mdev_type_attr_device_api.attr,
+	&mdev_type_attr_available_instances.attr,
+	NULL,
+};
+
+static struct attribute_group vfio_ap_mdev_hwvirt_type_group = {
+	.name = VFIO_AP_MDEV_TYPE_HWVIRT,
+	.attrs = vfio_ap_mdev_type_attrs,
+};
+
+static struct attribute_group *vfio_ap_mdev_type_groups[] = {
+	&vfio_ap_mdev_hwvirt_type_group,
+	NULL,
+};
+
+struct vfio_ap_queue_reserved {
+	unsigned long *apid;
+	unsigned long *apqi;
+	bool reserved;
+};
+
+/**
+ * vfio_ap_has_queue
+ *
+ * @dev: an AP queue device
+ * @data: a struct vfio_ap_queue_reserved reference
+ *
+ * Flags whether the AP queue device (@dev) has a queue ID containing the APQN,
+ * apid or apqi specified in @data:
+ *
+ * - If @data contains both an apid and apqi value, then @data will be flagged
+ *   as reserved if the APID and APQI fields for the AP queue device matches
+ *
+ * - If @data contains only an apid value, @data will be flagged as
+ *   reserved if the APID field in the AP queue device matches
+ *
+ * - If @data contains only an apqi value, @data will be flagged as
+ *   reserved if the APQI field in the AP queue device matches
+ *
+ * Returns 0 to indicate the input to function succeeded. Returns -EINVAL if
+ * @data does not contain either an apid or apqi.
+ */
+static int vfio_ap_has_queue(struct device *dev, void *data)
+{
+	struct vfio_ap_queue_reserved *qres = data;
+	struct ap_queue *ap_queue = to_ap_queue(dev);
+	ap_qid_t qid;
+	unsigned long id;
+
+	if (qres->apid && qres->apqi) {
+		qid = AP_MKQID(*qres->apid, *qres->apqi);
+		if (qid == ap_queue->qid)
+			qres->reserved = true;
+	} else if (qres->apid && !qres->apqi) {
+		id = AP_QID_CARD(ap_queue->qid);
+		if (id == *qres->apid)
+			qres->reserved = true;
+	} else if (!qres->apid && qres->apqi) {
+		id = AP_QID_QUEUE(ap_queue->qid);
+		if (id == *qres->apqi)
+			qres->reserved = true;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * vfio_ap_verify_queue_reserved
+ *
+ * @matrix_dev: a mediated matrix device
+ * @apid: an AP adapter ID
+ * @apqi: an AP queue index
+ *
+ * Verifies that the AP queue with @apid/@apqi is reserved by the VFIO AP device
+ * driver according to the following rules:
+ *
+ * - If both @apid and @apqi are not NULL, then there must be an AP queue
+ *   device bound to the vfio_ap driver with the APQN identified by @apid and
+ *   @apqi
+ *
+ * - If only @apid is not NULL, then there must be an AP queue device bound
+ *   to the vfio_ap driver with an APQN containing @apid
+ *
+ * - If only @apqi is not NULL, then there must be an AP queue device bound
+ *   to the vfio_ap driver with an APQN containing @apqi
+ *
+ * Returns 0 if the AP queue is reserved; otherwise, returns -EADDRNOTAVAIL.
+ */
+static int vfio_ap_verify_queue_reserved(unsigned long *apid,
+					 unsigned long *apqi)
+{
+	int ret;
+	struct vfio_ap_queue_reserved qres;
+
+	qres.apid = apid;
+	qres.apqi = apqi;
+	qres.reserved = false;
+
+	ret = driver_for_each_device(&matrix_dev->vfio_ap_drv->driver, NULL,
+				     &qres, vfio_ap_has_queue);
+	if (ret)
+		return ret;
+
+	if (qres.reserved)
+		return 0;
+
+	return -EADDRNOTAVAIL;
+}
+
+static int
+vfio_ap_mdev_verify_queues_reserved_for_apid(struct ap_matrix_mdev *matrix_mdev,
+					     unsigned long apid)
+{
+	int ret;
+	unsigned long apqi;
+	unsigned long nbits = matrix_mdev->matrix.aqm_max + 1;
+
+	if (find_first_bit_inv(matrix_mdev->matrix.aqm, nbits) >= nbits)
+		return vfio_ap_verify_queue_reserved(&apid, NULL);
+
+	for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, nbits) {
+		ret = vfio_ap_verify_queue_reserved(&apid, &apqi);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * vfio_ap_mdev_verify_no_sharing
+ *
+ * Verifies that the APQNs derived from the cross product of the AP adapter IDs
+ * and AP queue indexes comprising the AP matrix are not configured for another
+ * mediated device. AP queue sharing is not allowed.
+ *
+ * @matrix_mdev: the mediated matrix device
+ *
+ * Returns 0 if the APQNs are not shared, otherwise; returns -EADDRINUSE.
+ */
+static int vfio_ap_mdev_verify_no_sharing(struct ap_matrix_mdev *matrix_mdev)
+{
+	struct ap_matrix_mdev *lstdev;
+	DECLARE_BITMAP(apm, AP_DEVICES);
+	DECLARE_BITMAP(aqm, AP_DOMAINS);
+
+	list_for_each_entry(lstdev, &matrix_dev->mdev_list, node) {
+		if (matrix_mdev == lstdev)
+			continue;
+
+		memset(apm, 0, sizeof(apm));
+		memset(aqm, 0, sizeof(aqm));
+
+		/*
+		 * We work on full longs, as we can only exclude the leftover
+		 * bits in non-inverse order. The leftover is all zeros.
+		 */
+		if (!bitmap_and(apm, matrix_mdev->matrix.apm,
+				lstdev->matrix.apm, AP_DEVICES))
+			continue;
+
+		if (!bitmap_and(aqm, matrix_mdev->matrix.aqm,
+				lstdev->matrix.aqm, AP_DOMAINS))
+			continue;
+
+		return -EADDRINUSE;
+	}
+
+	return 0;
+}
+
+/**
+ * assign_adapter_store
+ *
+ * @dev:	the matrix device
+ * @attr:	the mediated matrix device's assign_adapter attribute
+ * @buf:	a buffer containing the AP adapter number (APID) to
+ *		be assigned
+ * @count:	the number of bytes in @buf
+ *
+ * Parses the APID from @buf and sets the corresponding bit in the mediated
+ * matrix device's APM.
+ *
+ * Returns the number of bytes processed if the APID is valid; otherwise,
+ * returns one of the following errors:
+ *
+ *	1. -EINVAL
+ *	   The APID is not a valid number
+ *
+ *	2. -ENODEV
+ *	   The APID exceeds the maximum value configured for the system
+ *
+ *	3. -EADDRNOTAVAIL
+ *	   An APQN derived from the cross product of the APID being assigned
+ *	   and the APQIs previously assigned is not bound to the vfio_ap device
+ *	   driver; or, if no APQIs have yet been assigned, the APID is not
+ *	   contained in an APQN bound to the vfio_ap device driver.
+ *
+ *	4. -EADDRINUSE
+ *	   An APQN derived from the cross product of the APID being assigned
+ *	   and the APQIs previously assigned is being used by another mediated
+ *	   matrix device
+ */
+static ssize_t assign_adapter_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	int ret;
+	unsigned long apid;
+	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;
+
+	if (apid > matrix_mdev->matrix.apm_max)
+		return -ENODEV;
+
+	/*
+	 * Set the bit in the AP mask (APM) corresponding to the AP adapter
+	 * number (APID). The bits in the mask, from most significant to least
+	 * significant bit, correspond to APIDs 0-255.
+	 */
+	mutex_lock(&matrix_dev->lock);
+
+	ret = vfio_ap_mdev_verify_queues_reserved_for_apid(matrix_mdev, apid);
+	if (ret)
+		goto done;
+
+	set_bit_inv(apid, matrix_mdev->matrix.apm);
+
+	ret = vfio_ap_mdev_verify_no_sharing(matrix_mdev);
+	if (ret)
+		goto share_err;
+
+	ret = count;
+	goto done;
+
+share_err:
+	clear_bit_inv(apid, matrix_mdev->matrix.apm);
+done:
+	mutex_unlock(&matrix_dev->lock);
+
+	return ret;
+}
+static DEVICE_ATTR_WO(assign_adapter);
+
+/**
+ * unassign_adapter_store
+ *
+ * @dev:	the matrix device
+ * @attr:	the mediated matrix device's unassign_adapter attribute
+ * @buf:	a buffer containing the adapter number (APID) to be unassigned
+ * @count:	the number of bytes in @buf
+ *
+ * Parses the APID from @buf and clears the corresponding bit in the mediated
+ * matrix device's APM.
+ *
+ * Returns the number of bytes processed if the APID is valid; otherwise,
+ * returns one of the following errors:
+ *	-EINVAL if the APID is not a number
+ *	-ENODEV if the APID it exceeds the maximum value configured for the
+ *		system
+ */
+static ssize_t unassign_adapter_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	int ret;
+	unsigned long apid;
+	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;
+
+	if (apid > matrix_mdev->matrix.apm_max)
+		return -ENODEV;
+
+	mutex_lock(&matrix_dev->lock);
+	clear_bit_inv((unsigned long)apid, matrix_mdev->matrix.apm);
+	mutex_unlock(&matrix_dev->lock);
+
+	return count;
+}
+static DEVICE_ATTR_WO(unassign_adapter);
+
+static int
+vfio_ap_mdev_verify_queues_reserved_for_apqi(struct ap_matrix_mdev *matrix_mdev,
+					     unsigned long apqi)
+{
+	int ret;
+	unsigned long apid;
+	unsigned long nbits = matrix_mdev->matrix.apm_max + 1;
+
+	if (find_first_bit_inv(matrix_mdev->matrix.apm, nbits) >= nbits)
+		return vfio_ap_verify_queue_reserved(NULL, &apqi);
+
+	for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, nbits) {
+		ret = vfio_ap_verify_queue_reserved(&apid, &apqi);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * assign_domain_store
+ *
+ * @dev:	the matrix device
+ * @attr:	the mediated matrix device's assign_domain attribute
+ * @buf:	a buffer containing the AP queue index (APQI) of the domain to
+ *		be assigned
+ * @count:	the number of bytes in @buf
+ *
+ * Parses the APQI from @buf and sets the corresponding bit in the mediated
+ * matrix device's AQM.
+ *
+ * Returns the number of bytes processed if the APQI is valid; otherwise returns
+ * one of the following errors:
+ *
+ *	1. -EINVAL
+ *	   The APQI is not a valid number
+ *
+ *	2. -ENODEV
+ *	   The APQI exceeds the maximum value configured for the system
+ *
+ *	3. -EADDRNOTAVAIL
+ *	   An APQN derived from the cross product of the APQI being assigned
+ *	   and the APIDs previously assigned is not bound to the vfio_ap device
+ *	   driver; or, if no APIDs have yet been assigned, the APQI is not
+ *	   contained in an APQN bound to the vfio_ap device driver.
+ *
+ *	4. -EADDRINUSE
+ *	   An APQN derived from the cross product of the APQI being assigned
+ *	   and the APIDs previously assigned is being used by another mediated
+ *	   matrix device
+ */
+static ssize_t assign_domain_store(struct device *dev,
+				   struct device_attribute *attr,
+				   const char *buf, size_t count)
+{
+	int ret;
+	unsigned long apqi;
+	struct mdev_device *mdev = mdev_from_dev(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;
+	if (apqi > max_apqi)
+		return -ENODEV;
+
+	mutex_lock(&matrix_dev->lock);
+
+	ret = vfio_ap_mdev_verify_queues_reserved_for_apqi(matrix_mdev, apqi);
+	if (ret)
+		goto done;
+
+	set_bit_inv(apqi, matrix_mdev->matrix.aqm);
+
+	ret = vfio_ap_mdev_verify_no_sharing(matrix_mdev);
+	if (ret)
+		goto share_err;
+
+	ret = count;
+	goto done;
+
+share_err:
+	clear_bit_inv(apqi, matrix_mdev->matrix.aqm);
+done:
+	mutex_unlock(&matrix_dev->lock);
+
+	return ret;
+}
+static DEVICE_ATTR_WO(assign_domain);
+
+
+/**
+ * unassign_domain_store
+ *
+ * @dev:	the matrix device
+ * @attr:	the mediated matrix device's unassign_domain attribute
+ * @buf:	a buffer containing the AP queue index (APQI) of the domain to
+ *		be unassigned
+ * @count:	the number of bytes in @buf
+ *
+ * Parses the APQI from @buf and clears the corresponding bit in the
+ * mediated matrix device's AQM.
+ *
+ * Returns the number of bytes processed if the APQI is valid; otherwise,
+ * returns one of the following errors:
+ *	-EINVAL if the APQI is not a number
+ *	-ENODEV if the APQI exceeds the maximum value configured for the system
+ */
+static ssize_t unassign_domain_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	int ret;
+	unsigned long apqi;
+	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;
+
+	if (apqi > matrix_mdev->matrix.aqm_max)
+		return -ENODEV;
+
+	mutex_lock(&matrix_dev->lock);
+	clear_bit_inv((unsigned long)apqi, matrix_mdev->matrix.aqm);
+	mutex_unlock(&matrix_dev->lock);
+
+	return count;
+}
+static DEVICE_ATTR_WO(unassign_domain);
+
+/**
+ * assign_control_domain_store
+ *
+ * @dev:	the matrix device
+ * @attr:	the mediated matrix device's assign_control_domain attribute
+ * @buf:	a buffer containing the domain ID to be assigned
+ * @count:	the number of bytes in @buf
+ *
+ * Parses the domain ID from @buf and sets the corresponding bit in the mediated
+ * matrix device's ADM.
+ *
+ * Returns the number of bytes processed if the domain ID is valid; otherwise,
+ * returns one of the following errors:
+ *	-EINVAL if the ID is not a number
+ *	-ENODEV if the ID exceeds the maximum value configured for the system
+ */
+static ssize_t assign_control_domain_store(struct device *dev,
+					   struct device_attribute *attr,
+					   const char *buf, size_t count)
+{
+	int ret;
+	unsigned long id;
+	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;
+
+	if (id > matrix_mdev->matrix.adm_max)
+		return -ENODEV;
+
+	/* Set the bit in the ADM (bitmask) corresponding to the AP control
+	 * domain number (id). The bits in the mask, from most significant to
+	 * least significant, correspond to IDs 0 up to the one less than the
+	 * number of control domains that can be assigned.
+	 */
+	mutex_lock(&matrix_dev->lock);
+	set_bit_inv(id, matrix_mdev->matrix.adm);
+	mutex_unlock(&matrix_dev->lock);
+
+	return count;
+}
+static DEVICE_ATTR_WO(assign_control_domain);
+
+/**
+ * unassign_control_domain_store
+ *
+ * @dev:	the matrix device
+ * @attr:	the mediated matrix device's unassign_control_domain attribute
+ * @buf:	a buffer containing the domain ID to be unassigned
+ * @count:	the number of bytes in @buf
+ *
+ * Parses the domain ID from @buf and clears the corresponding bit in the
+ * mediated matrix device's ADM.
+ *
+ * Returns the number of bytes processed if the domain ID is valid; otherwise,
+ * returns one of the following errors:
+ *	-EINVAL if the ID is not a number
+ *	-ENODEV if the ID exceeds the maximum value configured for the system
+ */
+static ssize_t unassign_control_domain_store(struct device *dev,
+					     struct device_attribute *attr,
+					     const char *buf, size_t count)
+{
+	int ret;
+	unsigned long domid;
+	struct mdev_device *mdev = mdev_from_dev(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;
+	if (domid > max_domid)
+		return -ENODEV;
+
+	mutex_lock(&matrix_dev->lock);
+	clear_bit_inv(domid, matrix_mdev->matrix.adm);
+	mutex_unlock(&matrix_dev->lock);
+
+	return count;
+}
+static DEVICE_ATTR_WO(unassign_control_domain);
+
+static ssize_t control_domains_show(struct device *dev,
+				    struct device_attribute *dev_attr,
+				    char *buf)
+{
+	unsigned long id;
+	int nchars = 0;
+	int n;
+	char *bufpos = buf;
+	struct mdev_device *mdev = mdev_from_dev(dev);
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	unsigned long max_domid = matrix_mdev->matrix.adm_max;
+
+	mutex_lock(&matrix_dev->lock);
+	for_each_set_bit_inv(id, matrix_mdev->matrix.adm, max_domid + 1) {
+		n = sprintf(bufpos, "%04lx\n", id);
+		bufpos += n;
+		nchars += n;
+	}
+	mutex_unlock(&matrix_dev->lock);
+
+	return nchars;
+}
+static DEVICE_ATTR_RO(control_domains);
+
+static ssize_t matrix_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct mdev_device *mdev = mdev_from_dev(dev);
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	char *bufpos = buf;
+	unsigned long apid;
+	unsigned long apqi;
+	unsigned long apid1;
+	unsigned long apqi1;
+	unsigned long napm_bits = matrix_mdev->matrix.apm_max + 1;
+	unsigned long naqm_bits = matrix_mdev->matrix.aqm_max + 1;
+	int nchars = 0;
+	int n;
+
+	apid1 = find_first_bit_inv(matrix_mdev->matrix.apm, napm_bits);
+	apqi1 = find_first_bit_inv(matrix_mdev->matrix.aqm, naqm_bits);
+
+	mutex_lock(&matrix_dev->lock);
+
+	if ((apid1 < napm_bits) && (apqi1 < naqm_bits)) {
+		for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, napm_bits) {
+			for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm,
+					     naqm_bits) {
+				n = sprintf(bufpos, "%02lx.%04lx\n", apid,
+					    apqi);
+				bufpos += n;
+				nchars += n;
+			}
+		}
+	} else if (apid1 < napm_bits) {
+		for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, napm_bits) {
+			n = sprintf(bufpos, "%02lx.\n", apid);
+			bufpos += n;
+			nchars += n;
+		}
+	} else if (apqi1 < naqm_bits) {
+		for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, naqm_bits) {
+			n = sprintf(bufpos, ".%04lx\n", apqi);
+			bufpos += n;
+			nchars += n;
+		}
+	}
+
+	mutex_unlock(&matrix_dev->lock);
+
+	return nchars;
+}
+static DEVICE_ATTR_RO(matrix);
+
+static struct attribute *vfio_ap_mdev_attrs[] = {
+	&dev_attr_assign_adapter.attr,
+	&dev_attr_unassign_adapter.attr,
+	&dev_attr_assign_domain.attr,
+	&dev_attr_unassign_domain.attr,
+	&dev_attr_assign_control_domain.attr,
+	&dev_attr_unassign_control_domain.attr,
+	&dev_attr_control_domains.attr,
+	&dev_attr_matrix.attr,
+	NULL,
+};
+
+static struct attribute_group vfio_ap_mdev_attr_group = {
+	.attrs = vfio_ap_mdev_attrs
+};
+
+static const struct attribute_group *vfio_ap_mdev_attr_groups[] = {
+	&vfio_ap_mdev_attr_group,
+	NULL
+};
+
+/**
+ * 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;
+	kvm_get_kvm(kvm);
+	kvm->arch.crypto.pqap_hook = &matrix_mdev->pqap_hook;
+	mutex_unlock(&matrix_dev->lock);
+
+	return 0;
+}
+
+/*
+ * vfio_ap_mdev_iommu_notifier: IOMMU notifier callback
+ *
+ * @nb: The notifier block
+ * @action: Action to be taken
+ * @data: data associated with the request
+ *
+ * For an UNMAP request, unpin the guest IOVA (the NIB guest address we
+ * pinned before). Other requests are ignored.
+ *
+ */
+static int vfio_ap_mdev_iommu_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, iommu_notifier);
+
+	if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP) {
+		struct vfio_iommu_type1_dma_unmap *unmap = data;
+		unsigned long g_pfn = unmap->iova >> PAGE_SHIFT;
+
+		vfio_unpin_pages(mdev_dev(matrix_mdev->mdev), &g_pfn, 1);
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
+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;
+
+	kvm_arch_crypto_set_masks(matrix_mdev->kvm, matrix_mdev->matrix.apm,
+				  matrix_mdev->matrix.aqm,
+				  matrix_mdev->matrix.adm);
+
+	return NOTIFY_OK;
+}
+
+static struct vfio_ap_queue *vfio_ap_find_queue(int apqn)
+{
+	struct device *dev;
+	struct vfio_ap_queue *q = NULL;
+
+	dev = driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL,
+				 &apqn, match_apqn);
+	if (dev) {
+		q = dev_get_drvdata(dev);
+		put_device(dev);
+	}
+
+	return q;
+}
+
+int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,
+			     unsigned int retry)
+{
+	struct ap_queue_status status;
+	int ret;
+	int retry2 = 2;
+
+	if (!q)
+		return 0;
+
+retry_zapq:
+	status = ap_zapq(q->apqn);
+	switch (status.response_code) {
+	case AP_RESPONSE_NORMAL:
+		ret = 0;
+		break;
+	case AP_RESPONSE_RESET_IN_PROGRESS:
+		if (retry--) {
+			msleep(20);
+			goto retry_zapq;
+		}
+		ret = -EBUSY;
+		break;
+	case AP_RESPONSE_Q_NOT_AVAIL:
+	case AP_RESPONSE_DECONFIGURED:
+	case AP_RESPONSE_CHECKSTOPPED:
+		WARN_ON_ONCE(status.irq_enabled);
+		ret = -EBUSY;
+		goto free_resources;
+	default:
+		/* things are really broken, give up */
+		WARN(true, "PQAP/ZAPQ completed with invalid rc (%x)\n",
+		     status.response_code);
+		return -EIO;
+	}
+
+	/* wait for the reset to take effect */
+	while (retry2--) {
+		if (status.queue_empty && !status.irq_enabled)
+			break;
+		msleep(20);
+		status = ap_tapq(q->apqn, NULL);
+	}
+	WARN_ON_ONCE(retry2 <= 0);
+
+free_resources:
+	vfio_ap_free_aqic_resources(q);
+
+	return ret;
+}
+
+static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
+{
+	int ret;
+	int rc = 0;
+	unsigned long apid, apqi;
+	struct vfio_ap_queue *q;
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+
+	for_each_set_bit_inv(apid, matrix_mdev->matrix.apm,
+			     matrix_mdev->matrix.apm_max + 1) {
+		for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm,
+				     matrix_mdev->matrix.aqm_max + 1) {
+			q = vfio_ap_find_queue(AP_MKQID(apid, apqi));
+			ret = vfio_ap_mdev_reset_queue(q, 1);
+			/*
+			 * Regardless whether a queue turns out to be busy, or
+			 * is not operational, we need to continue resetting
+			 * the remaining queues.
+			 */
+			if (ret)
+				rc = ret;
+		}
+	}
+
+	return rc;
+}
+
+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;
+	}
+
+	matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier;
+	events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
+	ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
+				     &events, &matrix_mdev->iommu_notifier);
+	if (!ret)
+		return ret;
+
+	vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
+				 &matrix_mdev->group_notifier);
+	module_put(THIS_MODULE);
+	return ret;
+}
+
+static void vfio_ap_mdev_release(struct mdev_device *mdev)
+{
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+
+	mutex_lock(&matrix_dev->lock);
+	if (matrix_mdev->kvm) {
+		kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
+		matrix_mdev->kvm->arch.crypto.pqap_hook = NULL;
+		vfio_ap_mdev_reset_queues(mdev);
+		kvm_put_kvm(matrix_mdev->kvm);
+		matrix_mdev->kvm = NULL;
+	}
+	mutex_unlock(&matrix_dev->lock);
+
+	vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
+				 &matrix_mdev->iommu_notifier);
+	vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
+				 &matrix_mdev->group_notifier);
+	module_put(THIS_MODULE);
+}
+
+static int vfio_ap_mdev_get_device_info(unsigned long arg)
+{
+	unsigned long minsz;
+	struct vfio_device_info info;
+
+	minsz = offsetofend(struct vfio_device_info, num_irqs);
+
+	if (copy_from_user(&info, (void __user *)arg, minsz))
+		return -EFAULT;
+
+	if (info.argsz < minsz)
+		return -EINVAL;
+
+	info.flags = VFIO_DEVICE_FLAGS_AP | VFIO_DEVICE_FLAGS_RESET;
+	info.num_regions = 0;
+	info.num_irqs = 0;
+
+	return copy_to_user((void __user *)arg, &info, minsz) ? -EFAULT : 0;
+}
+
+static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev,
+				    unsigned int cmd, unsigned long arg)
+{
+	int ret;
+
+	mutex_lock(&matrix_dev->lock);
+	switch (cmd) {
+	case VFIO_DEVICE_GET_INFO:
+		ret = vfio_ap_mdev_get_device_info(arg);
+		break;
+	case VFIO_DEVICE_RESET:
+		ret = vfio_ap_mdev_reset_queues(mdev);
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+	mutex_unlock(&matrix_dev->lock);
+
+	return ret;
+}
+
+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,
+	.ioctl			= vfio_ap_mdev_ioctl,
+};
+
+int vfio_ap_mdev_register(void)
+{
+	atomic_set(&matrix_dev->available_instances, MAX_ZDEV_ENTRIES_EXT);
+
+	return mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_ops);
+}
+
+void vfio_ap_mdev_unregister(void)
+{
+	mdev_unregister_device(&matrix_dev->device);
+}