// SPDX-License-Identifier: GPL-2.0
/*
* VFIO based Physical Subchannel device driver
*
* Copyright IBM Corp. 2017
* Copyright Red Hat, Inc. 2019
*
* Author(s): Dong Jia Shi <[email protected]>
* Xiao Feng Ren <[email protected]>
* Cornelia Huck <[email protected]>
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/mdev.h>
#include <asm/isc.h>
#include "chp.h"
#include "ioasm.h"
#include "css.h"
#include "vfio_ccw_private.h"
struct workqueue_struct *vfio_ccw_work_q;
struct kmem_cache *vfio_ccw_io_region;
struct kmem_cache *vfio_ccw_cmd_region;
struct kmem_cache *vfio_ccw_schib_region;
struct kmem_cache *vfio_ccw_crw_region;
debug_info_t *vfio_ccw_debug_msg_id;
debug_info_t *vfio_ccw_debug_trace_id;
/*
* Helpers
*/
int vfio_ccw_sch_quiesce(struct subchannel *sch)
{
struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
DECLARE_COMPLETION_ONSTACK(completion);
int iretry, ret = 0;
/*
* Probably an impossible situation, after being called through
* FSM callbacks. But in the event it did, register a warning
* and return as if things were fine.
*/
if (WARN_ON(!private))
return 0;
iretry = 255;
do {
ret = cio_cancel_halt_clear(sch, &iretry);
if (ret == -EIO) {
pr_err("vfio_ccw: could not quiesce subchannel 0.%x.%04x!\n",
sch->schid.ssid, sch->schid.sch_no);
break;
}
/*
* Flush all I/O and wait for
* cancel/halt/clear completion.
*/
private->completion = &completion;
spin_unlock_irq(&sch->lock);
if (ret == -EBUSY)
wait_for_completion_timeout(&completion, 3*HZ);
private->completion = NULL;
flush_workqueue(vfio_ccw_work_q);
spin_lock_irq(&sch->lock);
ret = cio_disable_subchannel(sch);
} while (ret == -EBUSY);
return ret;
}
void vfio_ccw_sch_io_todo(struct work_struct *work)
{
struct vfio_ccw_private *private;
struct irb *irb;
bool is_final;
bool cp_is_finished = false;
private = container_of(work, struct vfio_ccw_private, io_work);
irb = &private->irb;
is_final = !(scsw_actl(&irb->scsw) &
(SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
if (scsw_is_solicited(&irb->scsw)) {
cp_update_scsw(&private->cp, &irb->scsw);
if (is_final && private->state == VFIO_CCW_STATE_CP_PENDING) {
cp_free(&private->cp);
cp_is_finished = true;
}
}
mutex_lock(&private->io_mutex);
memcpy(private->io_region->irb_area, irb, sizeof(*irb));
mutex_unlock(&private->io_mutex);
/*
* Reset to IDLE only if processing of a channel program
* has finished. Do not overwrite a possible processing
* state if the interrupt was unsolicited, or if the final
* interrupt was for HSCH or CSCH.
*/
if (cp_is_finished)
private->state = VFIO_CCW_STATE_IDLE;
if (private->io_trigger)
eventfd_signal(private->io_trigger);
}
void vfio_ccw_crw_todo(struct work_struct *work)
{
struct vfio_ccw_private *private;
private = container_of(work, struct vfio_ccw_private, crw_work);
if (!list_empty(&private->crw) && private->crw_trigger)
eventfd_signal(private->crw_trigger);
}
/*
* Css driver callbacks
*/
static void vfio_ccw_sch_irq(struct subchannel *sch)
{
struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
/*
* The subchannel should still be disabled at this point,
* so an interrupt would be quite surprising. As with an
* interrupt while the FSM is closed, let's attempt to
* disable the subchannel again.
*/
if (!private) {
VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: unexpected interrupt\n",
sch->schid.cssid, sch->schid.ssid,
sch->schid.sch_no);
cio_disable_subchannel(sch);
return;
}
inc_irq_stat(IRQIO_CIO);
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
}
static void vfio_ccw_free_parent(struct device *dev)
{
struct vfio_ccw_parent *parent = container_of(dev, struct vfio_ccw_parent, dev);
kfree(parent);
}
static int vfio_ccw_sch_probe(struct subchannel *sch)
{
struct pmcw *pmcw = &sch->schib.pmcw;
struct vfio_ccw_parent *parent;
int ret = -ENOMEM;
if (pmcw->qf) {
dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
dev_name(&sch->dev));
return -ENODEV;
}
parent = kzalloc(struct_size(parent, mdev_types, 1), GFP_KERNEL);
if (!parent)
return -ENOMEM;
dev_set_name(&parent->dev, "parent");
parent->dev.parent = &sch->dev;
parent->dev.release = &vfio_ccw_free_parent;
ret = device_register(&parent->dev);
if (ret)
goto out_free;
dev_set_drvdata(&sch->dev, parent);
parent->mdev_type.sysfs_name = "io";
parent->mdev_type.pretty_name = "I/O subchannel (Non-QDIO)";
parent->mdev_types[0] = &parent->mdev_type;
ret = mdev_register_parent(&parent->parent, &sch->dev,
&vfio_ccw_mdev_driver,
parent->mdev_types, 1);
if (ret)
goto out_unreg;
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_unreg:
device_del(&parent->dev);
out_free:
put_device(&parent->dev);
dev_set_drvdata(&sch->dev, NULL);
return ret;
}
static void vfio_ccw_sch_remove(struct subchannel *sch)
{
struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
mdev_unregister_parent(&parent->parent);
device_unregister(&parent->dev);
dev_set_drvdata(&sch->dev, NULL);
VFIO_CCW_MSG_EVENT(4, "unbound from subchannel %x.%x.%04x\n",
sch->schid.cssid, sch->schid.ssid,
sch->schid.sch_no);
}
static void vfio_ccw_sch_shutdown(struct subchannel *sch)
{
struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
if (!private)
return;
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
}
/**
* vfio_ccw_sch_event - process subchannel event
* @sch: subchannel
* @process: non-zero if function is called in process context
*
* An unspecified event occurred for this subchannel. Adjust data according
* to the current operational state of the subchannel. Return zero when the
* event has been handled sufficiently or -EAGAIN when this function should
* be called again in process context.
*/
static int vfio_ccw_sch_event(struct subchannel *sch, int process)
{
struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
unsigned long flags;
int rc = -EAGAIN;
spin_lock_irqsave(&sch->lock, flags);
if (!device_is_registered(&sch->dev))
goto out_unlock;
if (work_pending(&sch->todo_work))
goto out_unlock;
rc = 0;
if (cio_update_schib(sch)) {
if (private)
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
}
out_unlock:
spin_unlock_irqrestore(&sch->lock, flags);
return rc;
}
static void vfio_ccw_queue_crw(struct vfio_ccw_private *private,
unsigned int rsc,
unsigned int erc,
unsigned int rsid)
{
struct vfio_ccw_crw *crw;
/*
* If unable to allocate a CRW, just drop the event and
* carry on. The guest will either see a later one or
* learn when it issues its own store subchannel.
*/
crw = kzalloc(sizeof(*crw), GFP_ATOMIC);
if (!crw)
return;
/*
* Build the CRW based on the inputs given to us.
*/
crw->crw.rsc = rsc;
crw->crw.erc = erc;
crw->crw.rsid = rsid;
list_add_tail(&crw->next, &private->crw);
queue_work(vfio_ccw_work_q, &private->crw_work);
}
static int vfio_ccw_chp_event(struct subchannel *sch,
struct chp_link *link, int event)
{
struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
int mask = chp_ssd_get_mask(&sch->ssd_info, link);
int retry = 255;
if (!private || !mask)
return 0;
trace_vfio_ccw_chp_event(sch->schid, mask, event);
VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: mask=0x%x event=%d\n",
sch->schid.cssid,
sch->schid.ssid, sch->schid.sch_no,
mask, event);
if (cio_update_schib(sch))
return -ENODEV;
switch (event) {
case CHP_VARY_OFF:
/* Path logically turned off */
sch->opm &= ~mask;
sch->lpm &= ~mask;
if (sch->schib.pmcw.lpum & mask)
cio_cancel_halt_clear(sch, &retry);
break;
case CHP_OFFLINE:
/* Path is gone */
if (sch->schib.pmcw.lpum & mask)
cio_cancel_halt_clear(sch, &retry);
vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_PERRN,
link->chpid.id);
break;
case CHP_VARY_ON:
/* Path logically turned on */
sch->opm |= mask;
sch->lpm |= mask;
break;
case CHP_ONLINE:
/* Path became available */
sch->lpm |= mask & sch->opm;
vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_INIT,
link->chpid.id);
break;
}
return 0;
}
static struct css_device_id vfio_ccw_sch_ids[] = {
{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
{ /* end of list */ },
};
MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
static struct css_driver vfio_ccw_sch_driver = {
.drv = {
.name = "vfio_ccw",
.owner = THIS_MODULE,
},
.subchannel_type = vfio_ccw_sch_ids,
.irq = vfio_ccw_sch_irq,
.probe = vfio_ccw_sch_probe,
.remove = vfio_ccw_sch_remove,
.shutdown = vfio_ccw_sch_shutdown,
.sch_event = vfio_ccw_sch_event,
.chp_event = vfio_ccw_chp_event,
};
static int __init vfio_ccw_debug_init(void)
{
vfio_ccw_debug_msg_id = debug_register("vfio_ccw_msg", 16, 1,
11 * sizeof(long));
if (!vfio_ccw_debug_msg_id)
goto out_unregister;
debug_register_view(vfio_ccw_debug_msg_id, &debug_sprintf_view);
debug_set_level(vfio_ccw_debug_msg_id, 2);
vfio_ccw_debug_trace_id = debug_register("vfio_ccw_trace", 16, 1, 16);
if (!vfio_ccw_debug_trace_id)
goto out_unregister;
debug_register_view(vfio_ccw_debug_trace_id, &debug_hex_ascii_view);
debug_set_level(vfio_ccw_debug_trace_id, 2);
return 0;
out_unregister:
debug_unregister(vfio_ccw_debug_msg_id);
debug_unregister(vfio_ccw_debug_trace_id);
return -1;
}
static void vfio_ccw_debug_exit(void)
{
debug_unregister(vfio_ccw_debug_msg_id);
debug_unregister(vfio_ccw_debug_trace_id);
}
static void vfio_ccw_destroy_regions(void)
{
kmem_cache_destroy(vfio_ccw_crw_region);
kmem_cache_destroy(vfio_ccw_schib_region);
kmem_cache_destroy(vfio_ccw_cmd_region);
kmem_cache_destroy(vfio_ccw_io_region);
}
static int __init vfio_ccw_sch_init(void)
{
int ret;
ret = vfio_ccw_debug_init();
if (ret)
return ret;
vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
if (!vfio_ccw_work_q) {
ret = -ENOMEM;
goto out_regions;
}
vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
sizeof(struct ccw_io_region), 0,
SLAB_ACCOUNT, 0,
sizeof(struct ccw_io_region), NULL);
if (!vfio_ccw_io_region) {
ret = -ENOMEM;
goto out_regions;
}
vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
sizeof(struct ccw_cmd_region), 0,
SLAB_ACCOUNT, 0,
sizeof(struct ccw_cmd_region), NULL);
if (!vfio_ccw_cmd_region) {
ret = -ENOMEM;
goto out_regions;
}
vfio_ccw_schib_region = kmem_cache_create_usercopy("vfio_ccw_schib_region",
sizeof(struct ccw_schib_region), 0,
SLAB_ACCOUNT, 0,
sizeof(struct ccw_schib_region), NULL);
if (!vfio_ccw_schib_region) {
ret = -ENOMEM;
goto out_regions;
}
vfio_ccw_crw_region = kmem_cache_create_usercopy("vfio_ccw_crw_region",
sizeof(struct ccw_crw_region), 0,
SLAB_ACCOUNT, 0,
sizeof(struct ccw_crw_region), NULL);
if (!vfio_ccw_crw_region) {
ret = -ENOMEM;
goto out_regions;
}
ret = mdev_register_driver(&vfio_ccw_mdev_driver);
if (ret)
goto out_regions;
isc_register(VFIO_CCW_ISC);
ret = css_driver_register(&vfio_ccw_sch_driver);
if (ret) {
isc_unregister(VFIO_CCW_ISC);
goto out_driver;
}
return ret;
out_driver:
mdev_unregister_driver(&vfio_ccw_mdev_driver);
out_regions:
vfio_ccw_destroy_regions();
destroy_workqueue(vfio_ccw_work_q);
vfio_ccw_debug_exit();
return ret;
}
static void __exit vfio_ccw_sch_exit(void)
{
css_driver_unregister(&vfio_ccw_sch_driver);
mdev_unregister_driver(&vfio_ccw_mdev_driver);
isc_unregister(VFIO_CCW_ISC);
vfio_ccw_destroy_regions();
destroy_workqueue(vfio_ccw_work_q);
vfio_ccw_debug_exit();
}
module_init(vfio_ccw_sch_init);
module_exit(vfio_ccw_sch_exit);
MODULE_DESCRIPTION("VFIO based Subchannel device driver");
MODULE_LICENSE("GPL v2");
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