From 204b394a23ad5e30944f23518e21e844614da2ff Mon Sep 17 00:00:00 2001 From: Eric Farman Date: Thu, 7 Jul 2022 15:57:37 +0200 Subject: [PATCH] vfio/ccw: Move FSM open/close to MDEV open/close Part of the confusion that has existed is the FSM lifecycle of subchannels between the common CSS driver and the vfio-ccw driver. During configuration, the FSM state goes from NOT_OPER to STANDBY to IDLE, but then back to NOT_OPER. For example: vfio_ccw_sch_probe: VFIO_CCW_STATE_NOT_OPER vfio_ccw_sch_probe: VFIO_CCW_STATE_STANDBY vfio_ccw_mdev_probe: VFIO_CCW_STATE_IDLE vfio_ccw_mdev_remove: VFIO_CCW_STATE_NOT_OPER vfio_ccw_sch_remove: VFIO_CCW_STATE_NOT_OPER vfio_ccw_sch_shutdown: VFIO_CCW_STATE_NOT_OPER Rearrange the open/close events to align with the mdev open/close, to better manage the memory and state of the devices as time progresses. Specifically, make mdev_open() perform the FSM open, and mdev_close() perform the FSM close instead of reset (which is both close and open). This makes the NOT_OPER state a dead-end path, indicating the device is probably not recoverable without fully probing and re-configuring the device. This has the nice side-effect of removing a number of special-cases where the FSM state is managed outside of the FSM itself (such as the aforementioned mdev_close() routine). Suggested-by: Jason Gunthorpe Signed-off-by: Eric Farman Reviewed-by: Jason Gunthorpe Reviewed-by: Matthew Rosato Link: https://lore.kernel.org/r/20220707135737.720765-12-farman@linux.ibm.com Signed-off-by: Alex Williamson --- drivers/s390/cio/vfio_ccw_drv.c | 11 +++-------- drivers/s390/cio/vfio_ccw_fsm.c | 34 +++++++++++++++++++++++++--------- drivers/s390/cio/vfio_ccw_ops.c | 26 +++++++++++--------------- 3 files changed, 39 insertions(+), 32 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c index f98c991..4804101 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -138,7 +138,7 @@ static struct vfio_ccw_private *vfio_ccw_alloc_private(struct subchannel *sch) private->sch = sch; mutex_init(&private->io_mutex); - private->state = VFIO_CCW_STATE_NOT_OPER; + private->state = VFIO_CCW_STATE_STANDBY; INIT_LIST_HEAD(&private->crw); INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo); INIT_WORK(&private->crw_work, vfio_ccw_crw_todo); @@ -222,21 +222,15 @@ static int vfio_ccw_sch_probe(struct subchannel *sch) dev_set_drvdata(&sch->dev, private); - vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_OPEN); - if (private->state == VFIO_CCW_STATE_NOT_OPER) - goto out_free; - ret = mdev_register_device(&sch->dev, &vfio_ccw_mdev_driver); if (ret) - goto out_disable; + goto out_free; VFIO_CCW_MSG_EVENT(4, "bound to subchannel %x.%x.%04x\n", sch->schid.cssid, sch->schid.ssid, sch->schid.sch_no); return 0; -out_disable: - cio_disable_subchannel(sch); out_free: dev_set_drvdata(&sch->dev, NULL); vfio_ccw_free_private(private); @@ -264,6 +258,7 @@ static void vfio_ccw_sch_shutdown(struct subchannel *sch) struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev); vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE); + vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER); } /** diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c index 89eb3fe..4b8b623 100644 --- a/drivers/s390/cio/vfio_ccw_fsm.c +++ b/drivers/s390/cio/vfio_ccw_fsm.c @@ -175,6 +175,9 @@ static void fsm_notoper(struct vfio_ccw_private *private, */ css_sched_sch_todo(sch, SCH_TODO_UNREG); private->state = VFIO_CCW_STATE_NOT_OPER; + + /* This is usually handled during CLOSE event */ + cp_free(&private->cp); } /* @@ -379,9 +382,16 @@ static void fsm_open(struct vfio_ccw_private *private, spin_lock_irq(sch->lock); sch->isc = VFIO_CCW_ISC; ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch); - if (!ret) - private->state = VFIO_CCW_STATE_STANDBY; + if (ret) + goto err_unlock; + + private->state = VFIO_CCW_STATE_IDLE; spin_unlock_irq(sch->lock); + return; + +err_unlock: + spin_unlock_irq(sch->lock); + vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER); } static void fsm_close(struct vfio_ccw_private *private, @@ -393,16 +403,22 @@ static void fsm_close(struct vfio_ccw_private *private, spin_lock_irq(sch->lock); if (!sch->schib.pmcw.ena) - goto out_unlock; + goto err_unlock; ret = cio_disable_subchannel(sch); if (ret == -EBUSY) vfio_ccw_sch_quiesce(sch); + if (ret) + goto err_unlock; -out_unlock: - private->state = VFIO_CCW_STATE_NOT_OPER; + private->state = VFIO_CCW_STATE_STANDBY; spin_unlock_irq(sch->lock); cp_free(&private->cp); + return; + +err_unlock: + spin_unlock_irq(sch->lock); + vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER); } /* @@ -414,16 +430,16 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = { [VFIO_CCW_EVENT_IO_REQ] = fsm_io_error, [VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_error, [VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq, - [VFIO_CCW_EVENT_OPEN] = fsm_open, + [VFIO_CCW_EVENT_OPEN] = fsm_nop, [VFIO_CCW_EVENT_CLOSE] = fsm_nop, }, [VFIO_CCW_STATE_STANDBY] = { [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper, [VFIO_CCW_EVENT_IO_REQ] = fsm_io_error, [VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_error, - [VFIO_CCW_EVENT_INTERRUPT] = fsm_irq, - [VFIO_CCW_EVENT_OPEN] = fsm_notoper, - [VFIO_CCW_EVENT_CLOSE] = fsm_close, + [VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq, + [VFIO_CCW_EVENT_OPEN] = fsm_open, + [VFIO_CCW_EVENT_CLOSE] = fsm_notoper, }, [VFIO_CCW_STATE_IDLE] = { [VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper, diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c index 4673b7d..bc21764 100644 --- a/drivers/s390/cio/vfio_ccw_ops.c +++ b/drivers/s390/cio/vfio_ccw_ops.c @@ -24,17 +24,12 @@ static int vfio_ccw_mdev_reset(struct vfio_ccw_private *private) /* * If the FSM state is seen as Not Operational after closing * and re-opening the mdev, return an error. - * - * Otherwise, change the FSM from STANDBY to IDLE which is - * normally done by vfio_ccw_mdev_probe() in current lifecycle. */ vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE); vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_OPEN); if (private->state == VFIO_CCW_STATE_NOT_OPER) return -EINVAL; - private->state = VFIO_CCW_STATE_IDLE; - return 0; } @@ -121,8 +116,6 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev) vfio_init_group_dev(&private->vdev, &mdev->dev, &vfio_ccw_dev_ops); - private->state = VFIO_CCW_STATE_IDLE; - VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: create\n", private->sch->schid.cssid, private->sch->schid.ssid, @@ -137,7 +130,6 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev) err_atomic: vfio_uninit_group_dev(&private->vdev); atomic_inc(&private->avail); - private->state = VFIO_CCW_STATE_STANDBY; return ret; } @@ -165,6 +157,10 @@ static int vfio_ccw_mdev_open_device(struct vfio_device *vdev) unsigned long events = VFIO_IOMMU_NOTIFY_DMA_UNMAP; int ret; + /* Device cannot simply be opened again from this state */ + if (private->state == VFIO_CCW_STATE_NOT_OPER) + return -EINVAL; + private->nb.notifier_call = vfio_ccw_mdev_notifier; ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY, @@ -184,6 +180,12 @@ static int vfio_ccw_mdev_open_device(struct vfio_device *vdev) if (ret) goto out_unregister; + vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_OPEN); + if (private->state == VFIO_CCW_STATE_NOT_OPER) { + ret = -EINVAL; + goto out_unregister; + } + return ret; out_unregister: @@ -197,13 +199,7 @@ static void vfio_ccw_mdev_close_device(struct vfio_device *vdev) struct vfio_ccw_private *private = container_of(vdev, struct vfio_ccw_private, vdev); - if ((private->state != VFIO_CCW_STATE_NOT_OPER) && - (private->state != VFIO_CCW_STATE_STANDBY)) { - if (!vfio_ccw_mdev_reset(private)) - private->state = VFIO_CCW_STATE_STANDBY; - /* The state will be NOT_OPER on error. */ - } - + vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE); vfio_ccw_unregister_dev_regions(private); vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &private->nb); } -- 2.7.4