466 lines
11 KiB
C
466 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Finite state machine for vfio-ccw device handling
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*
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* Copyright IBM Corp. 2017
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* Copyright Red Hat, Inc. 2019
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*
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* Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
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* Cornelia Huck <cohuck@redhat.com>
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*/
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#include <linux/vfio.h>
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#include <asm/isc.h>
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#include "ioasm.h"
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#include "vfio_ccw_private.h"
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static int fsm_io_helper(struct vfio_ccw_private *private)
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{
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struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
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union orb *orb;
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int ccode;
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__u8 lpm;
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unsigned long flags;
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int ret;
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spin_lock_irqsave(sch->lock, flags);
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orb = cp_get_orb(&private->cp, sch);
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if (!orb) {
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ret = -EIO;
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goto out;
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}
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VFIO_CCW_TRACE_EVENT(5, "stIO");
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VFIO_CCW_TRACE_EVENT(5, dev_name(&sch->dev));
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/* Issue "Start Subchannel" */
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ccode = ssch(sch->schid, orb);
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VFIO_CCW_HEX_EVENT(5, &ccode, sizeof(ccode));
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switch (ccode) {
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case 0:
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/*
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* Initialize device status information
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*/
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sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND;
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ret = 0;
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private->state = VFIO_CCW_STATE_CP_PENDING;
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break;
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case 1: /* Status pending */
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case 2: /* Busy */
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ret = -EBUSY;
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break;
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case 3: /* Device/path not operational */
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{
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lpm = orb->cmd.lpm;
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if (lpm != 0)
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sch->lpm &= ~lpm;
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else
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sch->lpm = 0;
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if (cio_update_schib(sch))
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ret = -ENODEV;
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else
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ret = sch->lpm ? -EACCES : -ENODEV;
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break;
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}
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default:
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ret = ccode;
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}
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out:
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spin_unlock_irqrestore(sch->lock, flags);
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return ret;
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}
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static int fsm_do_halt(struct vfio_ccw_private *private)
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{
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struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
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unsigned long flags;
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int ccode;
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int ret;
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spin_lock_irqsave(sch->lock, flags);
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VFIO_CCW_TRACE_EVENT(2, "haltIO");
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VFIO_CCW_TRACE_EVENT(2, dev_name(&sch->dev));
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/* Issue "Halt Subchannel" */
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ccode = hsch(sch->schid);
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VFIO_CCW_HEX_EVENT(2, &ccode, sizeof(ccode));
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switch (ccode) {
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case 0:
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/*
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* Initialize device status information
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*/
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sch->schib.scsw.cmd.actl |= SCSW_ACTL_HALT_PEND;
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ret = 0;
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break;
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case 1: /* Status pending */
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case 2: /* Busy */
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ret = -EBUSY;
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break;
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case 3: /* Device not operational */
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ret = -ENODEV;
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break;
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default:
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ret = ccode;
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}
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spin_unlock_irqrestore(sch->lock, flags);
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return ret;
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}
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static int fsm_do_clear(struct vfio_ccw_private *private)
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{
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struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
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unsigned long flags;
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int ccode;
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int ret;
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spin_lock_irqsave(sch->lock, flags);
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VFIO_CCW_TRACE_EVENT(2, "clearIO");
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VFIO_CCW_TRACE_EVENT(2, dev_name(&sch->dev));
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/* Issue "Clear Subchannel" */
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ccode = csch(sch->schid);
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VFIO_CCW_HEX_EVENT(2, &ccode, sizeof(ccode));
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switch (ccode) {
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case 0:
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/*
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* Initialize device status information
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*/
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sch->schib.scsw.cmd.actl = SCSW_ACTL_CLEAR_PEND;
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/* TODO: check what else we might need to clear */
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ret = 0;
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break;
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case 3: /* Device not operational */
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ret = -ENODEV;
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break;
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default:
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ret = ccode;
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}
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spin_unlock_irqrestore(sch->lock, flags);
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return ret;
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}
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static void fsm_notoper(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
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VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: notoper event %x state %x\n",
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sch->schid.cssid,
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sch->schid.ssid,
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sch->schid.sch_no,
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event,
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private->state);
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/*
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* TODO:
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* Probably we should send the machine check to the guest.
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*/
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css_sched_sch_todo(sch, SCH_TODO_UNREG);
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private->state = VFIO_CCW_STATE_NOT_OPER;
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/* This is usually handled during CLOSE event */
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cp_free(&private->cp);
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}
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/*
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* No operation action.
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*/
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static void fsm_nop(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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}
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static void fsm_io_error(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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pr_err("vfio-ccw: FSM: I/O request from state:%d\n", private->state);
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private->io_region->ret_code = -EIO;
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}
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static void fsm_io_busy(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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private->io_region->ret_code = -EBUSY;
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}
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static void fsm_io_retry(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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private->io_region->ret_code = -EAGAIN;
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}
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static void fsm_async_error(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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struct ccw_cmd_region *cmd_region = private->cmd_region;
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pr_err("vfio-ccw: FSM: %s request from state:%d\n",
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cmd_region->command == VFIO_CCW_ASYNC_CMD_HSCH ? "halt" :
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cmd_region->command == VFIO_CCW_ASYNC_CMD_CSCH ? "clear" :
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"<unknown>", private->state);
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cmd_region->ret_code = -EIO;
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}
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static void fsm_async_retry(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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private->cmd_region->ret_code = -EAGAIN;
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}
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static void fsm_disabled_irq(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
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/*
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* An interrupt in a disabled state means a previous disable was not
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* successful - should not happen, but we try to disable again.
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*/
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cio_disable_subchannel(sch);
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}
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inline struct subchannel_id get_schid(struct vfio_ccw_private *p)
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{
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struct subchannel *sch = to_subchannel(p->vdev.dev->parent);
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return sch->schid;
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}
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/*
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* Deal with the ccw command request from the userspace.
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*/
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static void fsm_io_request(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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union orb *orb;
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union scsw *scsw = &private->scsw;
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struct ccw_io_region *io_region = private->io_region;
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char *errstr = "request";
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struct subchannel_id schid = get_schid(private);
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private->state = VFIO_CCW_STATE_CP_PROCESSING;
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memcpy(scsw, io_region->scsw_area, sizeof(*scsw));
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if (scsw->cmd.fctl & SCSW_FCTL_START_FUNC) {
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orb = (union orb *)io_region->orb_area;
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/* Don't try to build a cp if transport mode is specified. */
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if (orb->tm.b) {
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io_region->ret_code = -EOPNOTSUPP;
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VFIO_CCW_MSG_EVENT(2,
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"sch %x.%x.%04x: transport mode\n",
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schid.cssid,
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schid.ssid, schid.sch_no);
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errstr = "transport mode";
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goto err_out;
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}
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io_region->ret_code = cp_init(&private->cp, orb);
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if (io_region->ret_code) {
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VFIO_CCW_MSG_EVENT(2,
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"sch %x.%x.%04x: cp_init=%d\n",
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schid.cssid,
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schid.ssid, schid.sch_no,
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io_region->ret_code);
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errstr = "cp init";
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goto err_out;
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}
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io_region->ret_code = cp_prefetch(&private->cp);
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if (io_region->ret_code) {
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VFIO_CCW_MSG_EVENT(2,
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"sch %x.%x.%04x: cp_prefetch=%d\n",
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schid.cssid,
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schid.ssid, schid.sch_no,
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io_region->ret_code);
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errstr = "cp prefetch";
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cp_free(&private->cp);
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goto err_out;
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}
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/* Start channel program and wait for I/O interrupt. */
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io_region->ret_code = fsm_io_helper(private);
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if (io_region->ret_code) {
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VFIO_CCW_MSG_EVENT(2,
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"sch %x.%x.%04x: fsm_io_helper=%d\n",
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schid.cssid,
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schid.ssid, schid.sch_no,
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io_region->ret_code);
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errstr = "cp fsm_io_helper";
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cp_free(&private->cp);
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goto err_out;
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}
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return;
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} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
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VFIO_CCW_MSG_EVENT(2,
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"sch %x.%x.%04x: halt on io_region\n",
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schid.cssid,
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schid.ssid, schid.sch_no);
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/* halt is handled via the async cmd region */
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io_region->ret_code = -EOPNOTSUPP;
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goto err_out;
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} else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
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VFIO_CCW_MSG_EVENT(2,
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"sch %x.%x.%04x: clear on io_region\n",
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schid.cssid,
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schid.ssid, schid.sch_no);
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/* clear is handled via the async cmd region */
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io_region->ret_code = -EOPNOTSUPP;
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goto err_out;
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}
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err_out:
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private->state = VFIO_CCW_STATE_IDLE;
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trace_vfio_ccw_fsm_io_request(scsw->cmd.fctl, schid,
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io_region->ret_code, errstr);
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}
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/*
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* Deal with an async request from userspace.
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*/
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static void fsm_async_request(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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struct ccw_cmd_region *cmd_region = private->cmd_region;
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switch (cmd_region->command) {
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case VFIO_CCW_ASYNC_CMD_HSCH:
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cmd_region->ret_code = fsm_do_halt(private);
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break;
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case VFIO_CCW_ASYNC_CMD_CSCH:
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cmd_region->ret_code = fsm_do_clear(private);
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break;
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default:
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/* should not happen? */
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cmd_region->ret_code = -EINVAL;
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}
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trace_vfio_ccw_fsm_async_request(get_schid(private),
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cmd_region->command,
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cmd_region->ret_code);
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}
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/*
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* Got an interrupt for a normal io (state busy).
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*/
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static void fsm_irq(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
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struct irb *irb = this_cpu_ptr(&cio_irb);
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VFIO_CCW_TRACE_EVENT(6, "IRQ");
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VFIO_CCW_TRACE_EVENT(6, dev_name(&sch->dev));
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memcpy(&private->irb, irb, sizeof(*irb));
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queue_work(vfio_ccw_work_q, &private->io_work);
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if (private->completion)
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complete(private->completion);
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}
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static void fsm_open(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
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int ret;
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spin_lock_irq(sch->lock);
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sch->isc = VFIO_CCW_ISC;
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ret = cio_enable_subchannel(sch, (u32)virt_to_phys(sch));
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if (ret)
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goto err_unlock;
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private->state = VFIO_CCW_STATE_IDLE;
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spin_unlock_irq(sch->lock);
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return;
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err_unlock:
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spin_unlock_irq(sch->lock);
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vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
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}
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static void fsm_close(struct vfio_ccw_private *private,
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enum vfio_ccw_event event)
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{
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struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
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int ret;
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spin_lock_irq(sch->lock);
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if (!sch->schib.pmcw.ena)
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goto err_unlock;
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ret = cio_disable_subchannel(sch);
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if (ret == -EBUSY)
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ret = vfio_ccw_sch_quiesce(sch);
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if (ret)
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goto err_unlock;
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private->state = VFIO_CCW_STATE_STANDBY;
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spin_unlock_irq(sch->lock);
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cp_free(&private->cp);
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return;
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err_unlock:
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spin_unlock_irq(sch->lock);
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vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
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}
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/*
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* Device statemachine
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*/
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fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
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[VFIO_CCW_STATE_NOT_OPER] = {
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[VFIO_CCW_EVENT_NOT_OPER] = fsm_nop,
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[VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
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[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_error,
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[VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq,
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[VFIO_CCW_EVENT_OPEN] = fsm_nop,
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[VFIO_CCW_EVENT_CLOSE] = fsm_nop,
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},
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[VFIO_CCW_STATE_STANDBY] = {
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[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
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[VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
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[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_error,
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[VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq,
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[VFIO_CCW_EVENT_OPEN] = fsm_open,
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[VFIO_CCW_EVENT_CLOSE] = fsm_notoper,
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},
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[VFIO_CCW_STATE_IDLE] = {
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[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
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[VFIO_CCW_EVENT_IO_REQ] = fsm_io_request,
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[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_request,
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[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
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[VFIO_CCW_EVENT_OPEN] = fsm_notoper,
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[VFIO_CCW_EVENT_CLOSE] = fsm_close,
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},
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[VFIO_CCW_STATE_CP_PROCESSING] = {
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[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
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[VFIO_CCW_EVENT_IO_REQ] = fsm_io_retry,
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[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_retry,
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[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
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[VFIO_CCW_EVENT_OPEN] = fsm_notoper,
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[VFIO_CCW_EVENT_CLOSE] = fsm_close,
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},
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[VFIO_CCW_STATE_CP_PENDING] = {
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[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
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[VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy,
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[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_request,
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[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
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[VFIO_CCW_EVENT_OPEN] = fsm_notoper,
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[VFIO_CCW_EVENT_CLOSE] = fsm_close,
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},
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};
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