// SPDX-License-Identifier: GPL-2.0
/*
* Finite state machine for vfio-ccw device handling
*
* Copyright IBM Corp. 2017
* Copyright Red Hat, Inc. 2019
*
* Author(s): Dong Jia Shi <[email protected]>
* Cornelia Huck <[email protected]>
*/
#include <linux/vfio.h>
#include <asm/isc.h>
#include "ioasm.h"
#include "vfio_ccw_private.h"
static int fsm_io_helper(struct vfio_ccw_private *private)
{
struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
union orb *orb;
int ccode;
__u8 lpm;
unsigned long flags;
int ret;
spin_lock_irqsave(&sch->lock, flags);
orb = cp_get_orb(&private->cp, sch);
if (!orb) {
ret = -EIO;
goto out;
}
VFIO_CCW_TRACE_EVENT(5, "stIO");
VFIO_CCW_TRACE_EVENT(5, dev_name(&sch->dev));
/* Issue "Start Subchannel" */
ccode = ssch(sch->schid, orb);
VFIO_CCW_HEX_EVENT(5, &ccode, sizeof(ccode));
switch (ccode) {
case 0:
/*
* Initialize device status information
*/
sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND;
ret = 0;
private->state = VFIO_CCW_STATE_CP_PENDING;
break;
case 1: /* Status pending */
case 2: /* Busy */
ret = -EBUSY;
break;
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))
ret = -ENODEV;
else
ret = sch->lpm ? -EACCES : -ENODEV;
break;
}
default:
ret = ccode;
}
out:
spin_unlock_irqrestore(&sch->lock, flags);
return ret;
}
static int fsm_do_halt(struct vfio_ccw_private *private)
{
struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
unsigned long flags;
int ccode;
int ret;
spin_lock_irqsave(&sch->lock, flags);
VFIO_CCW_TRACE_EVENT(2, "haltIO");
VFIO_CCW_TRACE_EVENT(2, dev_name(&sch->dev));
/* Issue "Halt Subchannel" */
ccode = hsch(sch->schid);
VFIO_CCW_HEX_EVENT(2, &ccode, sizeof(ccode));
switch (ccode) {
case 0:
/*
* Initialize device status information
*/
sch->schib.scsw.cmd.actl |= SCSW_ACTL_HALT_PEND;
ret = 0;
break;
case 1: /* Status pending */
case 2: /* Busy */
ret = -EBUSY;
break;
case 3: /* Device not operational */
ret = -ENODEV;
break;
default:
ret = ccode;
}
spin_unlock_irqrestore(&sch->lock, flags);
return ret;
}
static int fsm_do_clear(struct vfio_ccw_private *private)
{
struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
unsigned long flags;
int ccode;
int ret;
spin_lock_irqsave(&sch->lock, flags);
VFIO_CCW_TRACE_EVENT(2, "clearIO");
VFIO_CCW_TRACE_EVENT(2, dev_name(&sch->dev));
/* Issue "Clear Subchannel" */
ccode = csch(sch->schid);
VFIO_CCW_HEX_EVENT(2, &ccode, sizeof(ccode));
switch (ccode) {
case 0:
/*
* Initialize device status information
*/
sch->schib.scsw.cmd.actl = SCSW_ACTL_CLEAR_PEND;
/* TODO: check what else we might need to clear */
ret = 0;
break;
case 3: /* Device not operational */
ret = -ENODEV;
break;
default:
ret = ccode;
}
spin_unlock_irqrestore(&sch->lock, flags);
return ret;
}
static void fsm_notoper(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: notoper event %x state %x\n",
sch->schid.cssid,
sch->schid.ssid,
sch->schid.sch_no,
event,
private->state);
/*
* 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;
/* This is usually handled during CLOSE event */
cp_free(&private->cp);
}
/*
* 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_io_retry(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
private->io_region->ret_code = -EAGAIN;
}
static void fsm_async_error(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
struct ccw_cmd_region *cmd_region = private->cmd_region;
pr_err("vfio-ccw: FSM: %s request from state:%d\n",
cmd_region->command == VFIO_CCW_ASYNC_CMD_HSCH ? "halt" :
cmd_region->command == VFIO_CCW_ASYNC_CMD_CSCH ? "clear" :
"<unknown>", private->state);
cmd_region->ret_code = -EIO;
}
static void fsm_async_retry(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
private->cmd_region->ret_code = -EAGAIN;
}
static void fsm_disabled_irq(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
/*
* 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);
}
inline struct subchannel_id get_schid(struct vfio_ccw_private *p)
{
struct subchannel *sch = to_subchannel(p->vdev.dev->parent);
return sch->schid;
}
/*
* 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;
char *errstr = "request";
struct subchannel_id schid = get_schid(private);
private->state = VFIO_CCW_STATE_CP_PROCESSING;
memcpy(scsw, io_region->scsw_area, sizeof(*scsw));
if (scsw->cmd.fctl & SCSW_FCTL_START_FUNC) {
orb = (union orb *)io_region->orb_area;
/* Don't try to build a cp if transport mode is specified. */
if (orb->tm.b) {
io_region->ret_code = -EOPNOTSUPP;
VFIO_CCW_MSG_EVENT(2,
"sch %x.%x.%04x: transport mode\n",
schid.cssid,
schid.ssid, schid.sch_no);
errstr = "transport mode";
goto err_out;
}
io_region->ret_code = cp_init(&private->cp, orb);
if (io_region->ret_code) {
VFIO_CCW_MSG_EVENT(2,
"sch %x.%x.%04x: cp_init=%d\n",
schid.cssid,
schid.ssid, schid.sch_no,
io_region->ret_code);
errstr = "cp init";
goto err_out;
}
io_region->ret_code = cp_prefetch(&private->cp);
if (io_region->ret_code) {
VFIO_CCW_MSG_EVENT(2,
"sch %x.%x.%04x: cp_prefetch=%d\n",
schid.cssid,
schid.ssid, schid.sch_no,
io_region->ret_code);
errstr = "cp prefetch";
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) {
VFIO_CCW_MSG_EVENT(2,
"sch %x.%x.%04x: fsm_io_helper=%d\n",
schid.cssid,
schid.ssid, schid.sch_no,
io_region->ret_code);
errstr = "cp fsm_io_helper";
cp_free(&private->cp);
goto err_out;
}
return;
} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
VFIO_CCW_MSG_EVENT(2,
"sch %x.%x.%04x: halt on io_region\n",
schid.cssid,
schid.ssid, schid.sch_no);
/* halt is handled via the async cmd region */
io_region->ret_code = -EOPNOTSUPP;
goto err_out;
} else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
VFIO_CCW_MSG_EVENT(2,
"sch %x.%x.%04x: clear on io_region\n",
schid.cssid,
schid.ssid, schid.sch_no);
/* clear is handled via the async cmd region */
io_region->ret_code = -EOPNOTSUPP;
goto err_out;
}
err_out:
private->state = VFIO_CCW_STATE_IDLE;
trace_vfio_ccw_fsm_io_request(scsw->cmd.fctl, schid,
io_region->ret_code, errstr);
}
/*
* Deal with an async request from userspace.
*/
static void fsm_async_request(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
struct ccw_cmd_region *cmd_region = private->cmd_region;
switch (cmd_region->command) {
case VFIO_CCW_ASYNC_CMD_HSCH:
cmd_region->ret_code = fsm_do_halt(private);
break;
case VFIO_CCW_ASYNC_CMD_CSCH:
cmd_region->ret_code = fsm_do_clear(private);
break;
default:
/* should not happen? */
cmd_region->ret_code = -EINVAL;
}
trace_vfio_ccw_fsm_async_request(get_schid(private),
cmd_region->command,
cmd_region->ret_code);
}
/*
* Got an interrupt for a normal io (state busy).
*/
static void fsm_irq(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
struct irb *irb = this_cpu_ptr(&cio_irb);
VFIO_CCW_TRACE_EVENT(6, "IRQ");
VFIO_CCW_TRACE_EVENT(6, dev_name(&sch->dev));
memcpy(&private->irb, irb, sizeof(*irb));
queue_work(vfio_ccw_work_q, &private->io_work);
if (private->completion)
complete(private->completion);
}
static void fsm_open(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
int ret;
spin_lock_irq(&sch->lock);
sch->isc = VFIO_CCW_ISC;
ret = cio_enable_subchannel(sch, (u32)virt_to_phys(sch));
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,
enum vfio_ccw_event event)
{
struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
int ret;
spin_lock_irq(&sch->lock);
if (!sch->schib.pmcw.ena)
goto err_unlock;
ret = cio_disable_subchannel(sch);
if (ret == -EBUSY)
ret = vfio_ccw_sch_quiesce(sch);
if (ret)
goto err_unlock;
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);
}
/*
* 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_ASYNC_REQ] = fsm_async_error,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq,
[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_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,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_request,
[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_request,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
[VFIO_CCW_EVENT_OPEN] = fsm_notoper,
[VFIO_CCW_EVENT_CLOSE] = fsm_close,
},
[VFIO_CCW_STATE_CP_PROCESSING] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_retry,
[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_retry,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
[VFIO_CCW_EVENT_OPEN] = fsm_notoper,
[VFIO_CCW_EVENT_CLOSE] = fsm_close,
},
[VFIO_CCW_STATE_CP_PENDING] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy,
[VFIO_CCW_EVENT_ASYNC_REQ] = fsm_async_request,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
[VFIO_CCW_EVENT_OPEN] = fsm_notoper,
[VFIO_CCW_EVENT_CLOSE] = fsm_close,
},
};
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