drivers/s390/cio/vfio_ccw_drv.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * VFIO based Physical Subchannel device driver
   4  *
   5  * Copyright IBM Corp. 2017
   6  *
   7  * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
   8  *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/device.h>
  14 #include <linux/slab.h>
  15 #include <linux/uuid.h>
  16 #include <linux/mdev.h>
  17
  18 #include <asm/isc.h>
  19
  20 #include "ioasm.h"
  21 #include "css.h"
  22 #include "vfio_ccw_private.h"
  23
  24 struct workqueue_struct *vfio_ccw_work_q;
  25
  26 /*
  27  * Helpers
  28  */
  29 int vfio_ccw_sch_quiesce(struct subchannel *sch)
  30 {
  31         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
  32         DECLARE_COMPLETION_ONSTACK(completion);
  33         int iretry, ret = 0;
  34
  35         spin_lock_irq(sch->lock);
  36         if (!sch->schib.pmcw.ena)
  37                 goto out_unlock;
  38         ret = cio_disable_subchannel(sch);
  39         if (ret != -EBUSY)
  40                 goto out_unlock;
  41
  42         do {
  43                 iretry = 255;
  44
  45                 ret = cio_cancel_halt_clear(sch, &iretry);
  46                 while (ret == -EBUSY) {
  47                         /*
  48                          * Flush all I/O and wait for
  49                          * cancel/halt/clear completion.
  50                          */
  51                         private->completion = &completion;
  52                         spin_unlock_irq(sch->lock);
  53
  54                         wait_for_completion_timeout(&completion, 3*HZ);
  55
  56                         spin_lock_irq(sch->lock);
  57                         private->completion = NULL;
  58                         flush_workqueue(vfio_ccw_work_q);
  59                         ret = cio_cancel_halt_clear(sch, &iretry);
  60                 };
  61
  62                 ret = cio_disable_subchannel(sch);
  63         } while (ret == -EBUSY);
  64 out_unlock:
  65         private->state = VFIO_CCW_STATE_NOT_OPER;
  66         spin_unlock_irq(sch->lock);
  67         return ret;
  68 }
  69
  70 static void vfio_ccw_sch_io_todo(struct work_struct *work)
  71 {
  72         struct vfio_ccw_private *private;
  73         struct irb *irb;
  74
  75         private = container_of(work, struct vfio_ccw_private, io_work);
  76         irb = &private->irb;
  77
  78         if (scsw_is_solicited(&irb->scsw)) {
  79                 cp_update_scsw(&private->cp, &irb->scsw);
  80                 cp_free(&private->cp);
  81         }
  82         memcpy(private->io_region.irb_area, irb, sizeof(*irb));
  83
  84         if (private->io_trigger)
  85                 eventfd_signal(private->io_trigger, 1);
  86
  87         if (private->mdev)
  88                 private->state = VFIO_CCW_STATE_IDLE;
  89 }
  90
  91 /*
  92  * Css driver callbacks
  93  */
  94 static void vfio_ccw_sch_irq(struct subchannel *sch)
  95 {
  96         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
  97
  98         inc_irq_stat(IRQIO_CIO);
  99         vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
 100 }
 101
 102 static int vfio_ccw_sch_probe(struct subchannel *sch)
 103 {
 104         struct pmcw *pmcw = &sch->schib.pmcw;
 105         struct vfio_ccw_private *private;
 106         int ret;
 107
 108         if (pmcw->qf) {
 109                 dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
 110                          dev_name(&sch->dev));
 111                 return -ENODEV;
 112         }
 113
 114         private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
 115         if (!private)
 116                 return -ENOMEM;
 117         private->sch = sch;
 118         dev_set_drvdata(&sch->dev, private);
 119
 120         spin_lock_irq(sch->lock);
 121         private->state = VFIO_CCW_STATE_NOT_OPER;
 122         sch->isc = VFIO_CCW_ISC;
 123         ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
 124         spin_unlock_irq(sch->lock);
 125         if (ret)
 126                 goto out_free;
 127
 128         ret = vfio_ccw_mdev_reg(sch);
 129         if (ret)
 130                 goto out_disable;
 131
 132         INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
 133         atomic_set(&private->avail, 1);
 134         private->state = VFIO_CCW_STATE_STANDBY;
 135
 136         return 0;
 137
 138 out_disable:
 139         cio_disable_subchannel(sch);
 140 out_free:
 141         dev_set_drvdata(&sch->dev, NULL);
 142         kfree(private);
 143         return ret;
 144 }
 145
 146 static int vfio_ccw_sch_remove(struct subchannel *sch)
 147 {
 148         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 149
 150         vfio_ccw_sch_quiesce(sch);
 151
 152         vfio_ccw_mdev_unreg(sch);
 153
 154         dev_set_drvdata(&sch->dev, NULL);
 155
 156         kfree(private);
 157
 158         return 0;
 159 }
 160
 161 static void vfio_ccw_sch_shutdown(struct subchannel *sch)
 162 {
 163         vfio_ccw_sch_quiesce(sch);
 164 }
 165
 166 /**
 167  * vfio_ccw_sch_event - process subchannel event
 168  * @sch: subchannel
 169  * @process: non-zero if function is called in process context
 170  *
 171  * An unspecified event occurred for this subchannel. Adjust data according
 172  * to the current operational state of the subchannel. Return zero when the
 173  * event has been handled sufficiently or -EAGAIN when this function should
 174  * be called again in process context.
 175  */
 176 static int vfio_ccw_sch_event(struct subchannel *sch, int process)
 177 {
 178         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 179         unsigned long flags;
 180         int rc = -EAGAIN;
 181
 182         spin_lock_irqsave(sch->lock, flags);
 183         if (!device_is_registered(&sch->dev))
 184                 goto out_unlock;
 185
 186         if (work_pending(&sch->todo_work))
 187                 goto out_unlock;
 188
 189         if (cio_update_schib(sch)) {
 190                 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
 191                 rc = 0;
 192                 goto out_unlock;
 193         }
 194
 195         private = dev_get_drvdata(&sch->dev);
 196         if (private->state == VFIO_CCW_STATE_NOT_OPER) {
 197                 private->state = private->mdev ? VFIO_CCW_STATE_IDLE :
 198                                  VFIO_CCW_STATE_STANDBY;
 199         }
 200         rc = 0;
 201
 202 out_unlock:
 203         spin_unlock_irqrestore(sch->lock, flags);
 204
 205         return rc;
 206 }
 207
 208 static struct css_device_id vfio_ccw_sch_ids[] = {
 209         { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
 210         { /* end of list */ },
 211 };
 212 MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
 213
 214 static struct css_driver vfio_ccw_sch_driver = {
 215         .drv = {
 216                 .name = "vfio_ccw",
 217                 .owner = THIS_MODULE,
 218         },
 219         .subchannel_type = vfio_ccw_sch_ids,
 220         .irq = vfio_ccw_sch_irq,
 221         .probe = vfio_ccw_sch_probe,
 222         .remove = vfio_ccw_sch_remove,
 223         .shutdown = vfio_ccw_sch_shutdown,
 224         .sch_event = vfio_ccw_sch_event,
 225 };
 226
 227 static int __init vfio_ccw_sch_init(void)
 228 {
 229         int ret;
 230
 231         vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
 232         if (!vfio_ccw_work_q)
 233                 return -ENOMEM;
 234
 235         isc_register(VFIO_CCW_ISC);
 236         ret = css_driver_register(&vfio_ccw_sch_driver);
 237         if (ret) {
 238                 isc_unregister(VFIO_CCW_ISC);
 239                 destroy_workqueue(vfio_ccw_work_q);
 240         }
 241
 242         return ret;
 243 }
 244
 245 static void __exit vfio_ccw_sch_exit(void)
 246 {
 247         css_driver_unregister(&vfio_ccw_sch_driver);
 248         isc_unregister(VFIO_CCW_ISC);
 249         destroy_workqueue(vfio_ccw_work_q);
 250 }
 251 module_init(vfio_ccw_sch_init);
 252 module_exit(vfio_ccw_sch_exit);
 253
 254 MODULE_LICENSE("GPL v2");