1 files changed, 491 insertions, 0 deletions

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
new file mode 100644
index 000000000..ff538a086
--- /dev/null
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -0,0 +1,491 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * VFIO based Physical Subchannel device driver
+ *
+ * Copyright IBM Corp. 2017
+ * Copyright Red Hat, Inc. 2019
+ *
+ * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
+ *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
+ *            Cornelia Huck <cohuck@redhat.com>
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/mdev.h>
+
+#include <asm/isc.h>
+
+#include "chp.h"
+#include "ioasm.h"
+#include "css.h"
+#include "vfio_ccw_private.h"
+
+struct workqueue_struct *vfio_ccw_work_q;
+struct kmem_cache *vfio_ccw_io_region;
+struct kmem_cache *vfio_ccw_cmd_region;
+struct kmem_cache *vfio_ccw_schib_region;
+struct kmem_cache *vfio_ccw_crw_region;
+
+debug_info_t *vfio_ccw_debug_msg_id;
+debug_info_t *vfio_ccw_debug_trace_id;
+
+/*
+ * Helpers
+ */
+int vfio_ccw_sch_quiesce(struct subchannel *sch)
+{
+	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
+	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
+	DECLARE_COMPLETION_ONSTACK(completion);
+	int iretry, ret = 0;
+
+	/*
+	 * Probably an impossible situation, after being called through
+	 * FSM callbacks. But in the event it did, register a warning
+	 * and return as if things were fine.
+	 */
+	if (WARN_ON(!private))
+		return 0;
+
+	iretry = 255;
+	do {
+
+		ret = cio_cancel_halt_clear(sch, &iretry);
+
+		if (ret == -EIO) {
+			pr_err("vfio_ccw: could not quiesce subchannel 0.%x.%04x!\n",
+			       sch->schid.ssid, sch->schid.sch_no);
+			break;
+		}
+
+		/*
+		 * Flush all I/O and wait for
+		 * cancel/halt/clear completion.
+		 */
+		private->completion = &completion;
+		spin_unlock_irq(sch->lock);
+
+		if (ret == -EBUSY)
+			wait_for_completion_timeout(&completion, 3*HZ);
+
+		private->completion = NULL;
+		flush_workqueue(vfio_ccw_work_q);
+		spin_lock_irq(sch->lock);
+		ret = cio_disable_subchannel(sch);
+	} while (ret == -EBUSY);
+
+	return ret;
+}
+
+void vfio_ccw_sch_io_todo(struct work_struct *work)
+{
+	struct vfio_ccw_private *private;
+	struct irb *irb;
+	bool is_final;
+	bool cp_is_finished = false;
+
+	private = container_of(work, struct vfio_ccw_private, io_work);
+	irb = &private->irb;
+
+	is_final = !(scsw_actl(&irb->scsw) &
+		     (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
+	if (scsw_is_solicited(&irb->scsw)) {
+		cp_update_scsw(&private->cp, &irb->scsw);
+		if (is_final && private->state == VFIO_CCW_STATE_CP_PENDING) {
+			cp_free(&private->cp);
+			cp_is_finished = true;
+		}
+	}
+	mutex_lock(&private->io_mutex);
+	memcpy(private->io_region->irb_area, irb, sizeof(*irb));
+	mutex_unlock(&private->io_mutex);
+
+	/*
+	 * Reset to IDLE only if processing of a channel program
+	 * has finished. Do not overwrite a possible processing
+	 * state if the interrupt was unsolicited, or if the final
+	 * interrupt was for HSCH or CSCH.
+	 */
+	if (cp_is_finished)
+		private->state = VFIO_CCW_STATE_IDLE;
+
+	if (private->io_trigger)
+		eventfd_signal(private->io_trigger, 1);
+}
+
+void vfio_ccw_crw_todo(struct work_struct *work)
+{
+	struct vfio_ccw_private *private;
+
+	private = container_of(work, struct vfio_ccw_private, crw_work);
+
+	if (!list_empty(&private->crw) && private->crw_trigger)
+		eventfd_signal(private->crw_trigger, 1);
+}
+
+/*
+ * Css driver callbacks
+ */
+static void vfio_ccw_sch_irq(struct subchannel *sch)
+{
+	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
+	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
+
+	/*
+	 * The subchannel should still be disabled at this point,
+	 * so an interrupt would be quite surprising. As with an
+	 * interrupt while the FSM is closed, let's attempt to
+	 * disable the subchannel again.
+	 */
+	if (!private) {
+		VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: unexpected interrupt\n",
+				   sch->schid.cssid, sch->schid.ssid,
+				   sch->schid.sch_no);
+
+		cio_disable_subchannel(sch);
+		return;
+	}
+
+	inc_irq_stat(IRQIO_CIO);
+	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
+}
+
+static void vfio_ccw_free_parent(struct device *dev)
+{
+	struct vfio_ccw_parent *parent = container_of(dev, struct vfio_ccw_parent, dev);
+
+	kfree(parent);
+}
+
+static int vfio_ccw_sch_probe(struct subchannel *sch)
+{
+	struct pmcw *pmcw = &sch->schib.pmcw;
+	struct vfio_ccw_parent *parent;
+	int ret = -ENOMEM;
+
+	if (pmcw->qf) {
+		dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
+			 dev_name(&sch->dev));
+		return -ENODEV;
+	}
+
+	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
+	if (!parent)
+		return -ENOMEM;
+
+	dev_set_name(&parent->dev, "parent");
+	parent->dev.parent = &sch->dev;
+	parent->dev.release = &vfio_ccw_free_parent;
+	ret = device_register(&parent->dev);
+	if (ret)
+		goto out_free;
+
+	dev_set_drvdata(&sch->dev, parent);
+
+	parent->mdev_type.sysfs_name = "io";
+	parent->mdev_type.pretty_name = "I/O subchannel (Non-QDIO)";
+	parent->mdev_types[0] = &parent->mdev_type;
+	ret = mdev_register_parent(&parent->parent, &sch->dev,
+				   &vfio_ccw_mdev_driver,
+				   parent->mdev_types, 1);
+	if (ret)
+		goto out_unreg;
+
+	VFIO_CCW_MSG_EVENT(4, "bound to subchannel %x.%x.%04x\n",
+			   sch->schid.cssid, sch->schid.ssid,
+			   sch->schid.sch_no);
+	return 0;
+
+out_unreg:
+	device_del(&parent->dev);
+out_free:
+	put_device(&parent->dev);
+	dev_set_drvdata(&sch->dev, NULL);
+	return ret;
+}
+
+static void vfio_ccw_sch_remove(struct subchannel *sch)
+{
+	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
+
+	mdev_unregister_parent(&parent->parent);
+
+	device_unregister(&parent->dev);
+	dev_set_drvdata(&sch->dev, NULL);
+
+	VFIO_CCW_MSG_EVENT(4, "unbound from subchannel %x.%x.%04x\n",
+			   sch->schid.cssid, sch->schid.ssid,
+			   sch->schid.sch_no);
+}
+
+static void vfio_ccw_sch_shutdown(struct subchannel *sch)
+{
+	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
+	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
+
+	if (!private)
+		return;
+
+	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
+	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
+}
+
+/**
+ * vfio_ccw_sch_event - process subchannel event
+ * @sch: subchannel
+ * @process: non-zero if function is called in process context
+ *
+ * An unspecified event occurred for this subchannel. Adjust data according
+ * to the current operational state of the subchannel. Return zero when the
+ * event has been handled sufficiently or -EAGAIN when this function should
+ * be called again in process context.
+ */
+static int vfio_ccw_sch_event(struct subchannel *sch, int process)
+{
+	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
+	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
+	unsigned long flags;
+	int rc = -EAGAIN;
+
+	spin_lock_irqsave(sch->lock, flags);
+	if (!device_is_registered(&sch->dev))
+		goto out_unlock;
+
+	if (work_pending(&sch->todo_work))
+		goto out_unlock;
+
+	rc = 0;
+
+	if (cio_update_schib(sch)) {
+		if (private)
+			vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
+	}
+
+out_unlock:
+	spin_unlock_irqrestore(sch->lock, flags);
+
+	return rc;
+}
+
+static void vfio_ccw_queue_crw(struct vfio_ccw_private *private,
+			       unsigned int rsc,
+			       unsigned int erc,
+			       unsigned int rsid)
+{
+	struct vfio_ccw_crw *crw;
+
+	/*
+	 * If unable to allocate a CRW, just drop the event and
+	 * carry on.  The guest will either see a later one or
+	 * learn when it issues its own store subchannel.
+	 */
+	crw = kzalloc(sizeof(*crw), GFP_ATOMIC);
+	if (!crw)
+		return;
+
+	/*
+	 * Build the CRW based on the inputs given to us.
+	 */
+	crw->crw.rsc = rsc;
+	crw->crw.erc = erc;
+	crw->crw.rsid = rsid;
+
+	list_add_tail(&crw->next, &private->crw);
+	queue_work(vfio_ccw_work_q, &private->crw_work);
+}
+
+static int vfio_ccw_chp_event(struct subchannel *sch,
+			      struct chp_link *link, int event)
+{
+	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
+	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
+	int mask = chp_ssd_get_mask(&sch->ssd_info, link);
+	int retry = 255;
+
+	if (!private || !mask)
+		return 0;
+
+	trace_vfio_ccw_chp_event(sch->schid, mask, event);
+	VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: mask=0x%x event=%d\n",
+			   sch->schid.cssid,
+			   sch->schid.ssid, sch->schid.sch_no,
+			   mask, event);
+
+	if (cio_update_schib(sch))
+		return -ENODEV;
+
+	switch (event) {
+	case CHP_VARY_OFF:
+		/* Path logically turned off */
+		sch->opm &= ~mask;
+		sch->lpm &= ~mask;
+		if (sch->schib.pmcw.lpum & mask)
+			cio_cancel_halt_clear(sch, &retry);
+		break;
+	case CHP_OFFLINE:
+		/* Path is gone */
+		if (sch->schib.pmcw.lpum & mask)
+			cio_cancel_halt_clear(sch, &retry);
+		vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_PERRN,
+				   link->chpid.id);
+		break;
+	case CHP_VARY_ON:
+		/* Path logically turned on */
+		sch->opm |= mask;
+		sch->lpm |= mask;
+		break;
+	case CHP_ONLINE:
+		/* Path became available */
+		sch->lpm |= mask & sch->opm;
+		vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_INIT,
+				   link->chpid.id);
+		break;
+	}
+
+	return 0;
+}
+
+static struct css_device_id vfio_ccw_sch_ids[] = {
+	{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
+	{ /* end of list */ },
+};
+MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
+
+static struct css_driver vfio_ccw_sch_driver = {
+	.drv = {
+		.name = "vfio_ccw",
+		.owner = THIS_MODULE,
+	},
+	.subchannel_type = vfio_ccw_sch_ids,
+	.irq = vfio_ccw_sch_irq,
+	.probe = vfio_ccw_sch_probe,
+	.remove = vfio_ccw_sch_remove,
+	.shutdown = vfio_ccw_sch_shutdown,
+	.sch_event = vfio_ccw_sch_event,
+	.chp_event = vfio_ccw_chp_event,
+};
+
+static int __init vfio_ccw_debug_init(void)
+{
+	vfio_ccw_debug_msg_id = debug_register("vfio_ccw_msg", 16, 1,
+					       11 * sizeof(long));
+	if (!vfio_ccw_debug_msg_id)
+		goto out_unregister;
+	debug_register_view(vfio_ccw_debug_msg_id, &debug_sprintf_view);
+	debug_set_level(vfio_ccw_debug_msg_id, 2);
+	vfio_ccw_debug_trace_id = debug_register("vfio_ccw_trace", 16, 1, 16);
+	if (!vfio_ccw_debug_trace_id)
+		goto out_unregister;
+	debug_register_view(vfio_ccw_debug_trace_id, &debug_hex_ascii_view);
+	debug_set_level(vfio_ccw_debug_trace_id, 2);
+	return 0;
+
+out_unregister:
+	debug_unregister(vfio_ccw_debug_msg_id);
+	debug_unregister(vfio_ccw_debug_trace_id);
+	return -1;
+}
+
+static void vfio_ccw_debug_exit(void)
+{
+	debug_unregister(vfio_ccw_debug_msg_id);
+	debug_unregister(vfio_ccw_debug_trace_id);
+}
+
+static void vfio_ccw_destroy_regions(void)
+{
+	kmem_cache_destroy(vfio_ccw_crw_region);
+	kmem_cache_destroy(vfio_ccw_schib_region);
+	kmem_cache_destroy(vfio_ccw_cmd_region);
+	kmem_cache_destroy(vfio_ccw_io_region);
+}
+
+static int __init vfio_ccw_sch_init(void)
+{
+	int ret;
+
+	ret = vfio_ccw_debug_init();
+	if (ret)
+		return ret;
+
+	vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
+	if (!vfio_ccw_work_q) {
+		ret = -ENOMEM;
+		goto out_regions;
+	}
+
+	vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
+					sizeof(struct ccw_io_region), 0,
+					SLAB_ACCOUNT, 0,
+					sizeof(struct ccw_io_region), NULL);
+	if (!vfio_ccw_io_region) {
+		ret = -ENOMEM;
+		goto out_regions;
+	}
+
+	vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
+					sizeof(struct ccw_cmd_region), 0,
+					SLAB_ACCOUNT, 0,
+					sizeof(struct ccw_cmd_region), NULL);
+	if (!vfio_ccw_cmd_region) {
+		ret = -ENOMEM;
+		goto out_regions;
+	}
+
+	vfio_ccw_schib_region = kmem_cache_create_usercopy("vfio_ccw_schib_region",
+					sizeof(struct ccw_schib_region), 0,
+					SLAB_ACCOUNT, 0,
+					sizeof(struct ccw_schib_region), NULL);
+
+	if (!vfio_ccw_schib_region) {
+		ret = -ENOMEM;
+		goto out_regions;
+	}
+
+	vfio_ccw_crw_region = kmem_cache_create_usercopy("vfio_ccw_crw_region",
+					sizeof(struct ccw_crw_region), 0,
+					SLAB_ACCOUNT, 0,
+					sizeof(struct ccw_crw_region), NULL);
+
+	if (!vfio_ccw_crw_region) {
+		ret = -ENOMEM;
+		goto out_regions;
+	}
+
+	ret = mdev_register_driver(&vfio_ccw_mdev_driver);
+	if (ret)
+		goto out_regions;
+
+	isc_register(VFIO_CCW_ISC);
+	ret = css_driver_register(&vfio_ccw_sch_driver);
+	if (ret) {
+		isc_unregister(VFIO_CCW_ISC);
+		goto out_driver;
+	}
+
+	return ret;
+
+out_driver:
+	mdev_unregister_driver(&vfio_ccw_mdev_driver);
+out_regions:
+	vfio_ccw_destroy_regions();
+	destroy_workqueue(vfio_ccw_work_q);
+	vfio_ccw_debug_exit();
+	return ret;
+}
+
+static void __exit vfio_ccw_sch_exit(void)
+{
+	css_driver_unregister(&vfio_ccw_sch_driver);
+	mdev_unregister_driver(&vfio_ccw_mdev_driver);
+	isc_unregister(VFIO_CCW_ISC);
+	vfio_ccw_destroy_regions();
+	destroy_workqueue(vfio_ccw_work_q);
+	vfio_ccw_debug_exit();
+}
+module_init(vfio_ccw_sch_init);
+module_exit(vfio_ccw_sch_exit);
+
+MODULE_LICENSE("GPL v2");