drivers/s390/cio/vfio_ccw_fsm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Finite state machine for vfio-ccw device handling
   4  *
   5  * Copyright IBM Corp. 2017
   6  *
   7  * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
   8  */
   9
  10 #include <linux/vfio.h>
  11 #include <linux/mdev.h>
  12
  13 #include "ioasm.h"
  14 #include "vfio_ccw_private.h"
  15
  16 #define CREATE_TRACE_POINTS
  17 #include "vfio_ccw_trace.h"
  18
  19 static int fsm_io_helper(struct vfio_ccw_private *private)
  20 {
  21         struct subchannel *sch;
  22         union orb *orb;
  23         int ccode;
  24         __u8 lpm;
  25         unsigned long flags;
  26         int ret;
  27
  28         sch = private->sch;
  29
  30         spin_lock_irqsave(sch->lock, flags);
  31         private->state = VFIO_CCW_STATE_BUSY;
  32
  33         orb = cp_get_orb(&private->cp, (u32)(addr_t)sch, sch->lpm);
  34
  35         /* Issue "Start Subchannel" */
  36         ccode = ssch(sch->schid, orb);
  37
  38         switch (ccode) {
  39         case 0:
  40                 /*
  41                  * Initialize device status information
  42                  */
  43                 sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND;
  44                 ret = 0;
  45                 break;
  46         case 1:         /* Status pending */
  47         case 2:         /* Busy */
  48                 ret = -EBUSY;
  49                 break;
  50         case 3:         /* Device/path not operational */
  51         {
  52                 lpm = orb->cmd.lpm;
  53                 if (lpm != 0)
  54                         sch->lpm &= ~lpm;
  55                 else
  56                         sch->lpm = 0;
  57
  58                 if (cio_update_schib(sch))
  59                         ret = -ENODEV;
  60                 else
  61                         ret = sch->lpm ? -EACCES : -ENODEV;
  62                 break;
  63         }
  64         default:
  65                 ret = ccode;
  66         }
  67         spin_unlock_irqrestore(sch->lock, flags);
  68         return ret;
  69 }
  70
  71 static void fsm_notoper(struct vfio_ccw_private *private,
  72                         enum vfio_ccw_event event)
  73 {
  74         struct subchannel *sch = private->sch;
  75
  76         /*
  77          * TODO:
  78          * Probably we should send the machine check to the guest.
  79          */
  80         css_sched_sch_todo(sch, SCH_TODO_UNREG);
  81         private->state = VFIO_CCW_STATE_NOT_OPER;
  82 }
  83
  84 /*
  85  * No operation action.
  86  */
  87 static void fsm_nop(struct vfio_ccw_private *private,
  88                     enum vfio_ccw_event event)
  89 {
  90 }
  91
  92 static void fsm_io_error(struct vfio_ccw_private *private,
  93                          enum vfio_ccw_event event)
  94 {
  95         pr_err("vfio-ccw: FSM: I/O request from state:%d\n", private->state);
  96         private->io_region->ret_code = -EIO;
  97 }
  98
  99 static void fsm_io_busy(struct vfio_ccw_private *private,
 100                         enum vfio_ccw_event event)
 101 {
 102         private->io_region->ret_code = -EBUSY;
 103 }
 104
 105 static void fsm_disabled_irq(struct vfio_ccw_private *private,
 106                              enum vfio_ccw_event event)
 107 {
 108         struct subchannel *sch = private->sch;
 109
 110         /*
 111          * An interrupt in a disabled state means a previous disable was not
 112          * successful - should not happen, but we try to disable again.
 113          */
 114         cio_disable_subchannel(sch);
 115 }
 116 inline struct subchannel_id get_schid(struct vfio_ccw_private *p)
 117 {
 118         return p->sch->schid;
 119 }
 120
 121 /*
 122  * Deal with the ccw command request from the userspace.
 123  */
 124 static void fsm_io_request(struct vfio_ccw_private *private,
 125                            enum vfio_ccw_event event)
 126 {
 127         union orb *orb;
 128         union scsw *scsw = &private->scsw;
 129         struct ccw_io_region *io_region = private->io_region;
 130         struct mdev_device *mdev = private->mdev;
 131         char *errstr = "request";
 132
 133         private->state = VFIO_CCW_STATE_BOXED;
 134
 135         memcpy(scsw, io_region->scsw_area, sizeof(*scsw));
 136
 137         if (scsw->cmd.fctl & SCSW_FCTL_START_FUNC) {
 138                 orb = (union orb *)io_region->orb_area;
 139
 140                 /* Don't try to build a cp if transport mode is specified. */
 141                 if (orb->tm.b) {
 142                         io_region->ret_code = -EOPNOTSUPP;
 143                         errstr = "transport mode";
 144                         goto err_out;
 145                 }
 146                 io_region->ret_code = cp_init(&private->cp, mdev_dev(mdev),
 147                                               orb);
 148                 if (io_region->ret_code) {
 149                         errstr = "cp init";
 150                         goto err_out;
 151                 }
 152
 153                 io_region->ret_code = cp_prefetch(&private->cp);
 154                 if (io_region->ret_code) {
 155                         errstr = "cp prefetch";
 156                         cp_free(&private->cp);
 157                         goto err_out;
 158                 }
 159
 160                 /* Start channel program and wait for I/O interrupt. */
 161                 io_region->ret_code = fsm_io_helper(private);
 162                 if (io_region->ret_code) {
 163                         errstr = "cp fsm_io_helper";
 164                         cp_free(&private->cp);
 165                         goto err_out;
 166                 }
 167                 return;
 168         } else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
 169                 /* XXX: Handle halt. */
 170                 io_region->ret_code = -EOPNOTSUPP;
 171                 goto err_out;
 172         } else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
 173                 /* XXX: Handle clear. */
 174                 io_region->ret_code = -EOPNOTSUPP;
 175                 goto err_out;
 176         }
 177
 178 err_out:
 179         private->state = VFIO_CCW_STATE_IDLE;
 180         trace_vfio_ccw_io_fctl(scsw->cmd.fctl, get_schid(private),
 181                                io_region->ret_code, errstr);
 182 }
 183
 184 /*
 185  * Got an interrupt for a normal io (state busy).
 186  */
 187 static void fsm_irq(struct vfio_ccw_private *private,
 188                     enum vfio_ccw_event event)
 189 {
 190         struct irb *irb = this_cpu_ptr(&cio_irb);
 191
 192         memcpy(&private->irb, irb, sizeof(*irb));
 193
 194         queue_work(vfio_ccw_work_q, &private->io_work);
 195
 196         if (private->completion)
 197                 complete(private->completion);
 198 }
 199
 200 /*
 201  * Device statemachine
 202  */
 203 fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
 204         [VFIO_CCW_STATE_NOT_OPER] = {
 205                 [VFIO_CCW_EVENT_NOT_OPER]       = fsm_nop,
 206                 [VFIO_CCW_EVENT_IO_REQ]         = fsm_io_error,
 207                 [VFIO_CCW_EVENT_INTERRUPT]      = fsm_disabled_irq,
 208         },
 209         [VFIO_CCW_STATE_STANDBY] = {
 210                 [VFIO_CCW_EVENT_NOT_OPER]       = fsm_notoper,
 211                 [VFIO_CCW_EVENT_IO_REQ]         = fsm_io_error,
 212                 [VFIO_CCW_EVENT_INTERRUPT]      = fsm_irq,
 213         },
 214         [VFIO_CCW_STATE_IDLE] = {
 215                 [VFIO_CCW_EVENT_NOT_OPER]       = fsm_notoper,
 216                 [VFIO_CCW_EVENT_IO_REQ]         = fsm_io_request,
 217                 [VFIO_CCW_EVENT_INTERRUPT]      = fsm_irq,
 218         },
 219         [VFIO_CCW_STATE_BOXED] = {
 220                 [VFIO_CCW_EVENT_NOT_OPER]       = fsm_notoper,
 221                 [VFIO_CCW_EVENT_IO_REQ]         = fsm_io_busy,
 222                 [VFIO_CCW_EVENT_INTERRUPT]      = fsm_irq,
 223         },
 224         [VFIO_CCW_STATE_BUSY] = {
 225                 [VFIO_CCW_EVENT_NOT_OPER]       = fsm_notoper,
 226                 [VFIO_CCW_EVENT_IO_REQ]         = fsm_io_busy,
 227                 [VFIO_CCW_EVENT_INTERRUPT]      = fsm_irq,
 228         },
 229 };