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vfio-ccw: add handling for async channel instructions 

Add a region to the vfio-ccw device that can be used to submit
asynchronous I/O instructions. ssch continues to be handled by the
existing I/O region; the new region handles hsch and csch.

Interrupt status continues to be reported through the same channels
as for ssch.

Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
Cornelia Huck 2018-07-23 16:03:27 +02:00
parent b094085737
commit d5afd5d135
8 changed files with 270 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/s390/cio/Makefile
View File

@ -20,5 +20,6 @@ obj-$(CONFIG_CCWGROUP) += ccwgroup.o
qdio-objs := qdio_main.o qdio_thinint.o qdio_debug.o qdio_setup.o
obj-$(CONFIG_QDIO) += qdio.o
vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o vfio_ccw_ops.o vfio_ccw_fsm.o
vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o vfio_ccw_ops.o vfio_ccw_fsm.o \
vfio_ccw_async.o
obj-$(CONFIG_VFIO_CCW) += vfio_ccw.o

88
drivers/s390/cio/vfio_ccw_async.c Normal file
View File

@ -0,0 +1,88 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Async I/O region for vfio_ccw
*
* Copyright Red Hat, Inc. 2019
*
* Author(s): Cornelia Huck <cohuck@redhat.com>
*/
#include <linux/vfio.h>
#include <linux/mdev.h>
#include "vfio_ccw_private.h"
static ssize_t vfio_ccw_async_region_read(struct vfio_ccw_private *private,
char __user *buf, size_t count,
loff_t *ppos)
{
unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
struct ccw_cmd_region *region;
int ret;
if (pos + count > sizeof(*region))
return -EINVAL;
mutex_lock(&private->io_mutex);
region = private->region[i].data;
if (copy_to_user(buf, (void *)region + pos, count))
ret = -EFAULT;
else
ret = count;
mutex_unlock(&private->io_mutex);
return ret;
}
static ssize_t vfio_ccw_async_region_write(struct vfio_ccw_private *private,
const char __user *buf, size_t count,
loff_t *ppos)
{
unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
struct ccw_cmd_region *region;
int ret;
if (pos + count > sizeof(*region))
return -EINVAL;
if (!mutex_trylock(&private->io_mutex))
return -EAGAIN;
region = private->region[i].data;
if (copy_from_user((void *)region + pos, buf, count)) {
ret = -EFAULT;
goto out_unlock;
}
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_ASYNC_REQ);
ret = region->ret_code ? region->ret_code : count;
out_unlock:
mutex_unlock(&private->io_mutex);
return ret;
}
static void vfio_ccw_async_region_release(struct vfio_ccw_private *private,
struct vfio_ccw_region *region)
{
}
const struct vfio_ccw_regops vfio_ccw_async_region_ops = {
.read = vfio_ccw_async_region_read,
.write = vfio_ccw_async_region_write,
.release = vfio_ccw_async_region_release,
};
int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private)
{
return vfio_ccw_register_dev_region(private,
VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD,
&vfio_ccw_async_region_ops,
sizeof(struct ccw_cmd_region),
VFIO_REGION_INFO_FLAG_READ |
VFIO_REGION_INFO_FLAG_WRITE,
private->cmd_region);
}

44
drivers/s390/cio/vfio_ccw_drv.c
View File

@ -3,9 +3,11 @@
* VFIO based Physical Subchannel device driver
*
* Copyright IBM Corp. 2017
* Copyright Red Hat, Inc. 2019
*
* Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
* Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
* Cornelia Huck <cohuck@redhat.com>
*/
#include <linux/module.h>
@ -23,6 +25,7 @@
struct workqueue_struct *vfio_ccw_work_q;
static struct kmem_cache *vfio_ccw_io_region;
static struct kmem_cache *vfio_ccw_cmd_region;
/*
* Helpers
@ -110,7 +113,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
{
struct pmcw *pmcw = &sch->schib.pmcw;
struct vfio_ccw_private *private;
int ret;
int ret = -ENOMEM;
if (pmcw->qf) {
dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
@ -124,10 +127,13 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
private->io_region = kmem_cache_zalloc(vfio_ccw_io_region,
GFP_KERNEL | GFP_DMA);
if (!private->io_region) {
kfree(private);
return -ENOMEM;
}
if (!private->io_region)
goto out_free;
private->cmd_region = kmem_cache_zalloc(vfio_ccw_cmd_region,
GFP_KERNEL | GFP_DMA);
if (!private->cmd_region)
goto out_free;
private->sch = sch;
dev_set_drvdata(&sch->dev, private);
@ -155,6 +161,9 @@ out_disable:
cio_disable_subchannel(sch);
out_free:
dev_set_drvdata(&sch->dev, NULL);
if (private->cmd_region)
kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
if (private->io_region)
kmem_cache_free(vfio_ccw_io_region, private->io_region);
kfree(private);
return ret;
@ -170,6 +179,7 @@ static int vfio_ccw_sch_remove(struct subchannel *sch)
dev_set_drvdata(&sch->dev, NULL);
kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
kmem_cache_free(vfio_ccw_io_region, private->io_region);
kfree(private);
@ -244,7 +254,7 @@ static struct css_driver vfio_ccw_sch_driver = {
static int __init vfio_ccw_sch_init(void)
{
int ret;
int ret = -ENOMEM;
vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
if (!vfio_ccw_work_q)
@ -254,20 +264,30 @@ static int __init vfio_ccw_sch_init(void)
sizeof(struct ccw_io_region), 0,
SLAB_ACCOUNT, 0,
sizeof(struct ccw_io_region), NULL);
if (!vfio_ccw_io_region) {
destroy_workqueue(vfio_ccw_work_q);
return -ENOMEM;
}
if (!vfio_ccw_io_region)
goto out_err;
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)
goto out_err;
isc_register(VFIO_CCW_ISC);
ret = css_driver_register(&vfio_ccw_sch_driver);
if (ret) {
isc_unregister(VFIO_CCW_ISC);
kmem_cache_destroy(vfio_ccw_io_region);
destroy_workqueue(vfio_ccw_work_q);
goto out_err;
}
return ret;
out_err:
kmem_cache_destroy(vfio_ccw_cmd_region);
kmem_cache_destroy(vfio_ccw_io_region);
destroy_workqueue(vfio_ccw_work_q);
return ret;
}
static void __exit vfio_ccw_sch_exit(void)

119
drivers/s390/cio/vfio_ccw_fsm.c
View File

@ -3,8 +3,10 @@
* Finite state machine for vfio-ccw device handling
*
* Copyright IBM Corp. 2017
* Copyright Red Hat, Inc. 2019
*
* Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
* Cornelia Huck <cohuck@redhat.com>
*/
#include <linux/vfio.h>
@ -73,6 +75,75 @@ out:
return ret;
}
static int fsm_do_halt(struct vfio_ccw_private *private)
{
struct subchannel *sch;
unsigned long flags;
int ccode;
int ret;
sch = private->sch;
spin_lock_irqsave(sch->lock, flags);
/* Issue "Halt Subchannel" */
ccode = hsch(sch->schid);
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;
unsigned long flags;
int ccode;
int ret;
sch = private->sch;
spin_lock_irqsave(sch->lock, flags);
/* Issue "Clear Subchannel" */
ccode = csch(sch->schid);
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)
{
@ -113,6 +184,24 @@ static void fsm_io_retry(struct vfio_ccw_private *private,
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)
{
@ -176,11 +265,11 @@ static void fsm_io_request(struct vfio_ccw_private *private,
}
return;
} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
/* XXX: Handle halt. */
/* 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) {
/* XXX: Handle clear. */
/* clear is handled via the async cmd region */
io_region->ret_code = -EOPNOTSUPP;
goto err_out;
}
@ -190,6 +279,27 @@ err_out:
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;
}
}
/*
* Got an interrupt for a normal io (state busy).
*/
@ -213,26 +323,31 @@ 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_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_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_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_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,
},
};

11
drivers/s390/cio/vfio_ccw_ops.c
View File

@ -150,11 +150,20 @@ static int vfio_ccw_mdev_open(struct mdev_device *mdev)
struct vfio_ccw_private *private =
dev_get_drvdata(mdev_parent_dev(mdev));
unsigned long events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
int ret;
private->nb.notifier_call = vfio_ccw_mdev_notifier;
return vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
&events, &private->nb);
if (ret)
return ret;
ret = vfio_ccw_register_async_dev_regions(private);
if (ret)
vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
&private->nb);
return ret;
}
static void vfio_ccw_mdev_release(struct mdev_device *mdev)

5
drivers/s390/cio/vfio_ccw_private.h
View File

@ -53,6 +53,8 @@ int vfio_ccw_register_dev_region(struct vfio_ccw_private *private,
const struct vfio_ccw_regops *ops,
size_t size, u32 flags, void *data);
int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private);
/**
* struct vfio_ccw_private
* @sch: pointer to the subchannel
@ -64,6 +66,7 @@ int vfio_ccw_register_dev_region(struct vfio_ccw_private *private,
* @io_region: MMIO region to input/output I/O arguments/results
* @io_mutex: protect against concurrent update of I/O regions
* @region: additional regions for other subchannel operations
* @cmd_region: MMIO region for asynchronous I/O commands other than START
* @num_regions: number of additional regions
* @cp: channel program for the current I/O operation
* @irb: irb info received from interrupt
@ -81,6 +84,7 @@ struct vfio_ccw_private {
struct ccw_io_region *io_region;
struct mutex io_mutex;
struct vfio_ccw_region *region;
struct ccw_cmd_region *cmd_region;
int num_regions;
struct channel_program cp;
@ -116,6 +120,7 @@ enum vfio_ccw_event {
VFIO_CCW_EVENT_NOT_OPER,
VFIO_CCW_EVENT_IO_REQ,
VFIO_CCW_EVENT_INTERRUPT,
VFIO_CCW_EVENT_ASYNC_REQ,
/* last element! */
NR_VFIO_CCW_EVENTS
};

2
include/uapi/linux/vfio.h
View File

@ -354,6 +354,8 @@ struct vfio_region_gfx_edid {
};
#define VFIO_REGION_TYPE_CCW (2)
/* ccw sub-types */
#define VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD (1)
/*
* 10de vendor sub-type

12
include/uapi/linux/vfio_ccw.h
View File

@ -12,6 +12,7 @@
#include <linux/types.h>
/* used for START SUBCHANNEL, always present */
struct ccw_io_region {
#define ORB_AREA_SIZE 12
__u8 orb_area[ORB_AREA_SIZE];
@ -22,4 +23,15 @@ struct ccw_io_region {
__u32 ret_code;
} __packed;
/*
* used for processing commands that trigger asynchronous actions
* Note: this is controlled by a capability
*/
#define VFIO_CCW_ASYNC_CMD_HSCH (1 << 0)
#define VFIO_CCW_ASYNC_CMD_CSCH (1 << 1)
struct ccw_cmd_region {
__u32 command;
__u32 ret_code;
} __packed;
#endif