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;
27 spin_lock_irqsave(sch->lock, flags);
28 private->state = VFIO_CCW_STATE_BUSY;
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;
43 case 1: /* Status pending */
47 case 3: /* Device/path not operational */
55 if (cio_update_schib(sch))
58 ret = sch->lpm ? -EACCES : -ENODEV;
64 spin_unlock_irqrestore(sch->lock, flags);
68 static void fsm_notoper(struct vfio_ccw_private *private,
69 enum vfio_ccw_event event)
71 struct subchannel *sch = private->sch;
75 * Probably we should send the machine check to the guest.
77 css_sched_sch_todo(sch, SCH_TODO_UNREG);
78 private->state = VFIO_CCW_STATE_NOT_OPER;
82 * No operation action.
84 static void fsm_nop(struct vfio_ccw_private *private,
85 enum vfio_ccw_event event)
89 static void fsm_io_error(struct vfio_ccw_private *private,
90 enum vfio_ccw_event event)
92 pr_err("vfio-ccw: FSM: I/O request from state:%d\n", private->state);
93 private->io_region.ret_code = -EIO;
96 static void fsm_io_busy(struct vfio_ccw_private *private,
97 enum vfio_ccw_event event)
99 private->io_region.ret_code = -EBUSY;
102 static void fsm_disabled_irq(struct vfio_ccw_private *private,
103 enum vfio_ccw_event event)
105 struct subchannel *sch = private->sch;
108 * An interrupt in a disabled state means a previous disable was not
109 * successful - should not happen, but we try to disable again.
111 cio_disable_subchannel(sch);
115 * Deal with the ccw command request from the userspace.
117 static void fsm_io_request(struct vfio_ccw_private *private,
118 enum vfio_ccw_event event)
121 union scsw *scsw = &private->scsw;
122 struct ccw_io_region *io_region = &private->io_region;
123 struct mdev_device *mdev = private->mdev;
125 private->state = VFIO_CCW_STATE_BOXED;
127 memcpy(scsw, io_region->scsw_area, sizeof(*scsw));
129 if (scsw->cmd.fctl & SCSW_FCTL_START_FUNC) {
130 orb = (union orb *)io_region->orb_area;
132 /* Don't try to build a cp if transport mode is specified. */
134 io_region->ret_code = -EOPNOTSUPP;
137 io_region->ret_code = cp_init(&private->cp, mdev_dev(mdev),
139 if (io_region->ret_code)
142 io_region->ret_code = cp_prefetch(&private->cp);
143 if (io_region->ret_code) {
144 cp_free(&private->cp);
148 /* Start channel program and wait for I/O interrupt. */
149 io_region->ret_code = fsm_io_helper(private);
150 if (io_region->ret_code) {
151 cp_free(&private->cp);
155 } else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
156 /* XXX: Handle halt. */
157 io_region->ret_code = -EOPNOTSUPP;
159 } else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
160 /* XXX: Handle clear. */
161 io_region->ret_code = -EOPNOTSUPP;
166 private->state = VFIO_CCW_STATE_IDLE;
170 * Got an interrupt for a normal io (state busy).
172 static void fsm_irq(struct vfio_ccw_private *private,
173 enum vfio_ccw_event event)
175 struct irb *irb = this_cpu_ptr(&cio_irb);
177 memcpy(&private->irb, irb, sizeof(*irb));
179 queue_work(vfio_ccw_work_q, &private->io_work);
181 if (private->completion)
182 complete(private->completion);
186 * Device statemachine
188 fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
189 [VFIO_CCW_STATE_NOT_OPER] = {
190 [VFIO_CCW_EVENT_NOT_OPER] = fsm_nop,
191 [VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
192 [VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq,
194 [VFIO_CCW_STATE_STANDBY] = {
195 [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
196 [VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
197 [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
199 [VFIO_CCW_STATE_IDLE] = {
200 [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
201 [VFIO_CCW_EVENT_IO_REQ] = fsm_io_request,
202 [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
204 [VFIO_CCW_STATE_BOXED] = {
205 [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
206 [VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy,
207 [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
209 [VFIO_CCW_STATE_BUSY] = {
210 [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
211 [VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy,
212 [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,