vfio: ccw: introduce a finite state machine
The current implementation doesn't check if the subchannel is in a proper device state when handling an event. Let's introduce a finite state machine to manage the state/event change. Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Message-Id: <20170317031743.40128-14-bjsdjshi@linux.vnet.ibm.com> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
This commit is contained in:
Dong Jia Shi
Cornelia Huck
Родитель
e5f84dbaea
Коммит
bbe37e4cb8
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@ -18,5 +18,5 @@ obj-$(CONFIG_CCWGROUP) += ccwgroup.o
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qdio-objs := qdio_main.o qdio_thinint.o qdio_debug.o qdio_setup.o
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obj-$(CONFIG_QDIO) += qdio.o
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vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o vfio_ccw_ops.o
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vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o vfio_ccw_ops.o vfio_ccw_fsm.o
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obj-$(CONFIG_VFIO_CCW) += vfio_ccw.o
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@ -60,54 +60,12 @@ int vfio_ccw_sch_quiesce(struct subchannel *sch)
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ret = cio_disable_subchannel(sch);
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} while (ret == -EBUSY);
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out_unlock:
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private->state = VFIO_CCW_STATE_NOT_OPER;
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spin_unlock_irq(sch->lock);
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return ret;
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}
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static int vfio_ccw_sch_io_helper(struct vfio_ccw_private *private)
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{
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struct subchannel *sch;
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union orb *orb;
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int ccode;
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__u8 lpm;
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sch = private->sch;
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orb = cp_get_orb(&private->cp, (u32)(addr_t)sch, sch->lpm);
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/* Issue "Start Subchannel" */
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ccode = ssch(sch->schid, orb);
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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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return 0;
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case 1: /* Status pending */
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case 2: /* Busy */
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return -EBUSY;
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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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return -ENODEV;
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return sch->lpm ? -EACCES : -ENODEV;
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}
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default:
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return ccode;
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}
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}
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static void vfio_ccw_sch_io_todo(struct work_struct *work)
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{
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struct vfio_ccw_private *private;
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@ -126,47 +84,9 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work)
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if (private->io_trigger)
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eventfd_signal(private->io_trigger, 1);
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}
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/* Deal with the ccw command request from the userspace. */
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int vfio_ccw_sch_cmd_request(struct vfio_ccw_private *private)
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{
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struct mdev_device *mdev = private->mdev;
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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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int ret;
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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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ret = cp_init(&private->cp, mdev_dev(mdev), orb);
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if (ret)
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return ret;
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ret = cp_prefetch(&private->cp);
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if (ret) {
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cp_free(&private->cp);
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return ret;
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}
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/* Start channel program and wait for I/O interrupt. */
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ret = vfio_ccw_sch_io_helper(private);
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if (!ret)
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cp_free(&private->cp);
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} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
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/* XXX: Handle halt. */
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ret = -EOPNOTSUPP;
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} else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
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/* XXX: Handle clear. */
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ret = -EOPNOTSUPP;
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} else {
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ret = -EOPNOTSUPP;
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}
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return ret;
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if (private->mdev)
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private->state = VFIO_CCW_STATE_IDLE;
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}
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/*
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@ -223,20 +143,9 @@ static struct attribute_group vfio_subchannel_attr_group = {
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static void vfio_ccw_sch_irq(struct subchannel *sch)
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{
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struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
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struct irb *irb;
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inc_irq_stat(IRQIO_CIO);
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if (!private)
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return;
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irb = this_cpu_ptr(&cio_irb);
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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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vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
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}
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static int vfio_ccw_sch_probe(struct subchannel *sch)
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@ -258,6 +167,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
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dev_set_drvdata(&sch->dev, private);
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spin_lock_irq(sch->lock);
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private->state = VFIO_CCW_STATE_NOT_OPER;
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sch->isc = VFIO_CCW_ISC;
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ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
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spin_unlock_irq(sch->lock);
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@ -274,6 +184,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
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INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
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atomic_set(&private->avail, 1);
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private->state = VFIO_CCW_STATE_STANDBY;
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return 0;
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@ -321,6 +232,7 @@ static void vfio_ccw_sch_shutdown(struct subchannel *sch)
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*/
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static int vfio_ccw_sch_event(struct subchannel *sch, int process)
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{
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struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
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unsigned long flags;
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spin_lock_irqsave(sch->lock, flags);
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@ -331,16 +243,16 @@ static int vfio_ccw_sch_event(struct subchannel *sch, int process)
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goto out_unlock;
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if (cio_update_schib(sch)) {
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/* Not operational. */
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css_sched_sch_todo(sch, SCH_TODO_UNREG);
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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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vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
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goto out_unlock;
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}
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private = dev_get_drvdata(&sch->dev);
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if (private->state == VFIO_CCW_STATE_NOT_OPER) {
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private->state = private->mdev ? VFIO_CCW_STATE_IDLE :
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VFIO_CCW_STATE_STANDBY;
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}
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out_unlock:
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spin_unlock_irqrestore(sch->lock, flags);
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@ -0,0 +1,207 @@
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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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*
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* Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
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*/
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#include <linux/vfio.h>
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#include <linux/mdev.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;
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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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sch = private->sch;
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spin_lock_irqsave(sch->lock, flags);
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private->state = VFIO_CCW_STATE_BUSY;
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spin_unlock_irqrestore(sch->lock, flags);
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orb = cp_get_orb(&private->cp, (u32)(addr_t)sch, sch->lpm);
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/* Issue "Start Subchannel" */
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ccode = ssch(sch->schid, orb);
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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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return 0;
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case 1: /* Status pending */
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case 2: /* Busy */
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return -EBUSY;
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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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return -ENODEV;
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return sch->lpm ? -EACCES : -ENODEV;
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}
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default:
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return ccode;
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}
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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 = private->sch;
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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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}
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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_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 = private->sch;
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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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/*
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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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struct mdev_device *mdev = private->mdev;
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private->state = VFIO_CCW_STATE_BOXED;
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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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io_region->ret_code = cp_init(&private->cp, mdev_dev(mdev),
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orb);
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if (io_region->ret_code)
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goto err_out;
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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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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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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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/* XXX: Handle halt. */
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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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/* XXX: Handle clear. */
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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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}
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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 irb *irb;
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if (!private)
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return;
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irb = this_cpu_ptr(&cio_irb);
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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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/*
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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_INTERRUPT] = fsm_disabled_irq,
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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_INTERRUPT] = fsm_irq,
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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_INTERRUPT] = fsm_irq,
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},
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[VFIO_CCW_STATE_BOXED] = {
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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_INTERRUPT] = fsm_irq,
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},
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[VFIO_CCW_STATE_BUSY] = {
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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_INTERRUPT] = fsm_irq,
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},
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};
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@ -35,7 +35,11 @@ static int vfio_ccw_mdev_reset(struct mdev_device *mdev)
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if (ret)
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return ret;
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return cio_enable_subchannel(sch, (u32)(unsigned long)sch);
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ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
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if (!ret)
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private->state = VFIO_CCW_STATE_IDLE;
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return ret;
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}
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static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
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@ -112,10 +116,14 @@ static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
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struct vfio_ccw_private *private =
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dev_get_drvdata(mdev_parent_dev(mdev));
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if (private->state == VFIO_CCW_STATE_NOT_OPER)
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return -ENODEV;
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if (atomic_dec_if_positive(&private->avail) < 0)
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return -EPERM;
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private->mdev = mdev;
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private->state = VFIO_CCW_STATE_IDLE;
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return 0;
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}
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@ -126,10 +134,20 @@ static int vfio_ccw_mdev_remove(struct mdev_device *mdev)
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dev_get_drvdata(mdev_parent_dev(mdev));
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int ret;
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if (!private)
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goto out;
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if ((private->state == VFIO_CCW_STATE_NOT_OPER) ||
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(private->state == VFIO_CCW_STATE_STANDBY))
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goto out;
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ret = vfio_ccw_mdev_reset(mdev);
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if (ret)
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return ret;
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private->state = VFIO_CCW_STATE_STANDBY;
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out:
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private->mdev = NULL;
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atomic_inc(&private->avail);
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@ -193,14 +211,18 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
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private = dev_get_drvdata(mdev_parent_dev(mdev));
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if (!private)
|
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return -ENODEV;
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if (private->state != VFIO_CCW_STATE_IDLE)
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return -EACCES;
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region = &private->io_region;
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if (copy_from_user((void *)region + *ppos, buf, count))
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return -EFAULT;
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region->ret_code = vfio_ccw_sch_cmd_request(private);
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if (region->ret_code != 0)
|
||||
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_IO_REQ);
|
||||
if (region->ret_code != 0) {
|
||||
private->state = VFIO_CCW_STATE_IDLE;
|
||||
return region->ret_code;
|
||||
}
|
||||
|
||||
return count;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -21,6 +21,7 @@
|
|||
/**
|
||||
* struct vfio_ccw_private
|
||||
* @sch: pointer to the subchannel
|
||||
* @state: internal state of the device
|
||||
* @completion: synchronization helper of the I/O completion
|
||||
* @avail: available for creating a mediated device
|
||||
* @mdev: pointer to the mediated device
|
||||
|
|
@ -34,6 +35,7 @@
|
|||
*/
|
||||
struct vfio_ccw_private {
|
||||
struct subchannel *sch;
|
||||
int state;
|
||||
struct completion *completion;
|
||||
atomic_t avail;
|
||||
struct mdev_device *mdev;
|
||||
|
|
@ -52,6 +54,43 @@ extern int vfio_ccw_mdev_reg(struct subchannel *sch);
|
|||
extern void vfio_ccw_mdev_unreg(struct subchannel *sch);
|
||||
|
||||
extern int vfio_ccw_sch_quiesce(struct subchannel *sch);
|
||||
extern int vfio_ccw_sch_cmd_request(struct vfio_ccw_private *private);
|
||||
|
||||
/*
|
||||
* States of the device statemachine.
|
||||
*/
|
||||
enum vfio_ccw_state {
|
||||
VFIO_CCW_STATE_NOT_OPER,
|
||||
VFIO_CCW_STATE_STANDBY,
|
||||
VFIO_CCW_STATE_IDLE,
|
||||
VFIO_CCW_STATE_BOXED,
|
||||
VFIO_CCW_STATE_BUSY,
|
||||
/* last element! */
|
||||
NR_VFIO_CCW_STATES
|
||||
};
|
||||
|
||||
/*
|
||||
* Asynchronous events of the device statemachine.
|
||||
*/
|
||||
enum vfio_ccw_event {
|
||||
VFIO_CCW_EVENT_NOT_OPER,
|
||||
VFIO_CCW_EVENT_IO_REQ,
|
||||
VFIO_CCW_EVENT_INTERRUPT,
|
||||
/* last element! */
|
||||
NR_VFIO_CCW_EVENTS
|
||||
};
|
||||
|
||||
/*
|
||||
* Action called through jumptable.
|
||||
*/
|
||||
typedef void (fsm_func_t)(struct vfio_ccw_private *, enum vfio_ccw_event);
|
||||
extern fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS];
|
||||
|
||||
static inline void vfio_ccw_fsm_event(struct vfio_ccw_private *private,
|
||||
int event)
|
||||
{
|
||||
vfio_ccw_jumptable[private->state][event](private, event);
|
||||
}
|
||||
|
||||
extern struct workqueue_struct *vfio_ccw_work_q;
|
||||
|
||||
#endif
|
||||
|
|
|
|||
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