1 // SPDX-License-Identifier: GPL-2.0
3 * Finite state machine for vfio-ccw device handling
5 * Copyright IBM Corp. 2017
7 * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
10 #include <linux/vfio.h>
11 #include <linux/mdev.h>
14 #include "vfio_ccw_private.h"
16 static int fsm_io_helper(struct vfio_ccw_private *private)
18 struct subchannel *sch;
26 spin_lock_irqsave(sch->lock, flags);
27 private->state = VFIO_CCW_STATE_BUSY;
28 spin_unlock_irqrestore(sch->lock, flags);
30 orb = cp_get_orb(&private->cp, (u32)(addr_t)sch, sch->lpm);
32 /* Issue "Start Subchannel" */
33 ccode = ssch(sch->schid, orb);
38 * Initialize device status information
40 sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND;
42 case 1: /* Status pending */
45 case 3: /* Device/path not operational */
53 if (cio_update_schib(sch))
56 return sch->lpm ? -EACCES : -ENODEV;
63 static void fsm_notoper(struct vfio_ccw_private *private,
64 enum vfio_ccw_event event)
66 struct subchannel *sch = private->sch;
70 * Probably we should send the machine check to the guest.
72 css_sched_sch_todo(sch, SCH_TODO_UNREG);
73 private->state = VFIO_CCW_STATE_NOT_OPER;
77 * No operation action.
79 static void fsm_nop(struct vfio_ccw_private *private,
80 enum vfio_ccw_event event)
84 static void fsm_io_error(struct vfio_ccw_private *private,
85 enum vfio_ccw_event event)
87 pr_err("vfio-ccw: FSM: I/O request from state:%d\n", private->state);
88 private->io_region.ret_code = -EIO;
91 static void fsm_io_busy(struct vfio_ccw_private *private,
92 enum vfio_ccw_event event)
94 private->io_region.ret_code = -EBUSY;
97 static void fsm_disabled_irq(struct vfio_ccw_private *private,
98 enum vfio_ccw_event event)
100 struct subchannel *sch = private->sch;
103 * An interrupt in a disabled state means a previous disable was not
104 * successful - should not happen, but we try to disable again.
106 cio_disable_subchannel(sch);
110 * Deal with the ccw command request from the userspace.
112 static void fsm_io_request(struct vfio_ccw_private *private,
113 enum vfio_ccw_event event)
116 union scsw *scsw = &private->scsw;
117 struct ccw_io_region *io_region = &private->io_region;
118 struct mdev_device *mdev = private->mdev;
120 private->state = VFIO_CCW_STATE_BOXED;
122 memcpy(scsw, io_region->scsw_area, sizeof(*scsw));
124 if (scsw->cmd.fctl & SCSW_FCTL_START_FUNC) {
125 orb = (union orb *)io_region->orb_area;
127 /* Don't try to build a cp if transport mode is specified. */
129 io_region->ret_code = -EOPNOTSUPP;
132 io_region->ret_code = cp_init(&private->cp, mdev_dev(mdev),
134 if (io_region->ret_code)
137 io_region->ret_code = cp_prefetch(&private->cp);
138 if (io_region->ret_code) {
139 cp_free(&private->cp);
143 /* Start channel program and wait for I/O interrupt. */
144 io_region->ret_code = fsm_io_helper(private);
145 if (io_region->ret_code) {
146 cp_free(&private->cp);
150 } else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
151 /* XXX: Handle halt. */
152 io_region->ret_code = -EOPNOTSUPP;
154 } else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
155 /* XXX: Handle clear. */
156 io_region->ret_code = -EOPNOTSUPP;
161 private->state = VFIO_CCW_STATE_IDLE;
165 * Got an interrupt for a normal io (state busy).
167 static void fsm_irq(struct vfio_ccw_private *private,
168 enum vfio_ccw_event event)
170 struct irb *irb = this_cpu_ptr(&cio_irb);
172 memcpy(&private->irb, irb, sizeof(*irb));
174 queue_work(vfio_ccw_work_q, &private->io_work);
176 if (private->completion)
177 complete(private->completion);
181 * Device statemachine
183 fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
184 [VFIO_CCW_STATE_NOT_OPER] = {
185 [VFIO_CCW_EVENT_NOT_OPER] = fsm_nop,
186 [VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
187 [VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq,
189 [VFIO_CCW_STATE_STANDBY] = {
190 [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
191 [VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
192 [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
194 [VFIO_CCW_STATE_IDLE] = {
195 [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
196 [VFIO_CCW_EVENT_IO_REQ] = fsm_io_request,
197 [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
199 [VFIO_CCW_STATE_BOXED] = {
200 [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
201 [VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy,
202 [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
204 [VFIO_CCW_STATE_BUSY] = {
205 [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
206 [VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy,
207 [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,