diff options
Diffstat (limited to 'drivers/s390/cio/vfio_ccw_fsm.c')
| -rw-r--r-- | drivers/s390/cio/vfio_ccw_fsm.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c new file mode 100644 index 000000000000..80a0559cd7ce --- /dev/null +++ b/drivers/s390/cio/vfio_ccw_fsm.c @@ -0,0 +1,203 @@ +/* + * Finite state machine for vfio-ccw device handling + * + * Copyright IBM Corp. 2017 + * + * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> + */ + +#include <linux/vfio.h> +#include <linux/mdev.h> + +#include "ioasm.h" +#include "vfio_ccw_private.h" + +static int fsm_io_helper(struct vfio_ccw_private *private) +{ + struct subchannel *sch; + union orb *orb; + int ccode; + __u8 lpm; + unsigned long flags; + + sch = private->sch; + + spin_lock_irqsave(sch->lock, flags); + private->state = VFIO_CCW_STATE_BUSY; + spin_unlock_irqrestore(sch->lock, flags); + + orb = cp_get_orb(&private->cp, (u32)(addr_t)sch, sch->lpm); + + /* Issue "Start Subchannel" */ + ccode = ssch(sch->schid, orb); + + switch (ccode) { + case 0: + /* + * Initialize device status information + */ + sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND; + return 0; + case 1: /* Status pending */ + case 2: /* Busy */ + return -EBUSY; + case 3: /* Device/path not operational */ + { + lpm = orb->cmd.lpm; + if (lpm != 0) + sch->lpm &= ~lpm; + else + sch->lpm = 0; + + if (cio_update_schib(sch)) + return -ENODEV; + + return sch->lpm ? -EACCES : -ENODEV; + } + default: + return ccode; + } +} + +static void fsm_notoper(struct vfio_ccw_private *private, + enum vfio_ccw_event event) +{ + struct subchannel *sch = private->sch; + + /* + * TODO: + * Probably we should send the machine check to the guest. + */ + css_sched_sch_todo(sch, SCH_TODO_UNREG); + private->state = VFIO_CCW_STATE_NOT_OPER; +} + +/* + * No operation action. + */ +static void fsm_nop(struct vfio_ccw_private *private, + enum vfio_ccw_event event) +{ +} + +static void fsm_io_error(struct vfio_ccw_private *private, + enum vfio_ccw_event event) +{ + pr_err("vfio-ccw: FSM: I/O request from state:%d\n", private->state); + private->io_region.ret_code = -EIO; +} + +static void fsm_io_busy(struct vfio_ccw_private *private, + enum vfio_ccw_event event) +{ + private->io_region.ret_code = -EBUSY; +} + +static void fsm_disabled_irq(struct vfio_ccw_private *private, + enum vfio_ccw_event event) +{ + struct subchannel *sch = private->sch; + + /* + * An interrupt in a disabled state means a previous disable was not + * successful - should not happen, but we try to disable again. + */ + cio_disable_subchannel(sch); +} + +/* + * Deal with the ccw command request from the userspace. + */ +static void fsm_io_request(struct vfio_ccw_private *private, + enum vfio_ccw_event event) +{ + union orb *orb; + union scsw *scsw = &private->scsw; + struct ccw_io_region *io_region = &private->io_region; + struct mdev_device *mdev = private->mdev; + + private->state = VFIO_CCW_STATE_BOXED; + + memcpy(scsw, io_region->scsw_area, sizeof(*scsw)); + + if (scsw->cmd.fctl & SCSW_FCTL_START_FUNC) { + orb = (union orb *)io_region->orb_area; + + io_region->ret_code = cp_init(&private->cp, mdev_dev(mdev), + orb); + if (io_region->ret_code) + goto err_out; + + io_region->ret_code = cp_prefetch(&private->cp); + if (io_region->ret_code) { + cp_free(&private->cp); + goto err_out; + } + + /* Start channel program and wait for I/O interrupt. */ + io_region->ret_code = fsm_io_helper(private); + if (io_region->ret_code) { + cp_free(&private->cp); + goto err_out; + } + return; + } else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) { + /* XXX: Handle halt. */ + io_region->ret_code = -EOPNOTSUPP; + goto err_out; + } else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) { + /* XXX: Handle clear. */ + io_region->ret_code = -EOPNOTSUPP; + goto err_out; + } + +err_out: + private->state = VFIO_CCW_STATE_IDLE; +} + +/* + * Got an interrupt for a normal io (state busy). + */ +static void fsm_irq(struct vfio_ccw_private *private, + enum vfio_ccw_event event) +{ + struct irb *irb = this_cpu_ptr(&cio_irb); + + memcpy(&private->irb, irb, sizeof(*irb)); + + queue_work(vfio_ccw_work_q, &private->io_work); + + if (private->completion) + complete(private->completion); +} + +/* + * Device statemachine + */ +fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = { + [VFIO_CCW_STATE_NOT_OPER] = { + [VFIO_CCW_EVENT_NOT_OPER] = fsm_nop, + [VFIO_CCW_EVENT_IO_REQ] = fsm_io_error, + [VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq, + }, + [VFIO_CCW_STATE_STANDBY] = { + [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper, + [VFIO_CCW_EVENT_IO_REQ] = fsm_io_error, + [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq, + }, + [VFIO_CCW_STATE_IDLE] = { + [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper, + [VFIO_CCW_EVENT_IO_REQ] = fsm_io_request, + [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq, + }, + [VFIO_CCW_STATE_BOXED] = { + [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper, + [VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy, + [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq, + }, + [VFIO_CCW_STATE_BUSY] = { + [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper, + [VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy, + [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq, + }, +}; |