vfio: ccw: basic implementation for vfio_ccw driver

To make vfio support subchannel devices, we need a css driver for
the vfio subchannels. This patch adds a basic vfio-ccw subchannel
driver for this purpose.

To enable VFIO for vfio-ccw, enable S390_CCW_IOMMU config option
and configure VFIO as required.

Acked-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Message-Id: <20170317031743.40128-5-bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
This commit is contained in:
Dong Jia Shi 2017-03-17 04:17:31 +01:00 коммит произвёл Cornelia Huck
Родитель aec390b937
Коммит 63f1934d56
6 изменённых файлов: 309 добавлений и 0 удалений

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@ -672,6 +672,16 @@ config EADM_SCH
To compile this driver as a module, choose M here: the
module will be called eadm_sch.
config VFIO_CCW
def_tristate n
prompt "Support for VFIO-CCW subchannels"
depends on S390_CCW_IOMMU && VFIO
help
This driver allows usage of I/O subchannels via VFIO-CCW.
To compile this driver as a module, choose M here: the
module will be called vfio_ccw.
endmenu
menu "Dump support"

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@ -16,6 +16,7 @@
#define CONSOLE_ISC 1 /* console I/O subchannel */
#define EADM_SCH_ISC 4 /* EADM subchannels */
#define CHSC_SCH_ISC 7 /* CHSC subchannels */
#define VFIO_CCW_ISC IO_SCH_ISC /* VFIO-CCW I/O subchannels */
/* Adapter interrupts. */
#define QDIO_AIRQ_ISC IO_SCH_ISC /* I/O subchannel in qdio mode */
#define PCI_ISC 2 /* PCI I/O subchannels */

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@ -327,6 +327,14 @@ config S390_IOMMU
help
Support for the IOMMU API for s390 PCI devices.
config S390_CCW_IOMMU
bool "S390 CCW IOMMU Support"
depends on S390 && CCW
select IOMMU_API
help
Enables bits of IOMMU API required by VFIO. The iommu_ops
is not implemented as it is not necessary for VFIO.
config MTK_IOMMU
bool "MTK IOMMU Support"
depends on ARM || ARM64

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@ -17,3 +17,6 @@ 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
obj-$(CONFIG_VFIO_CCW) += vfio_ccw.o

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@ -0,0 +1,262 @@
/*
* VFIO based Physical Subchannel device driver
*
* Copyright IBM Corp. 2017
*
* Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
* Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <asm/isc.h>
#include "vfio_ccw_private.h"
/*
* Helpers
*/
static int vfio_ccw_sch_quiesce(struct subchannel *sch)
{
struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
DECLARE_COMPLETION_ONSTACK(completion);
int iretry, ret = 0;
spin_lock_irq(sch->lock);
if (!sch->schib.pmcw.ena)
goto out_unlock;
ret = cio_disable_subchannel(sch);
if (ret != -EBUSY)
goto out_unlock;
do {
iretry = 255;
ret = cio_cancel_halt_clear(sch, &iretry);
while (ret == -EBUSY) {
/*
* Flush all I/O and wait for
* cancel/halt/clear completion.
*/
private->completion = &completion;
spin_unlock_irq(sch->lock);
wait_for_completion_timeout(&completion, 3*HZ);
spin_lock_irq(sch->lock);
private->completion = NULL;
ret = cio_cancel_halt_clear(sch, &iretry);
};
ret = cio_disable_subchannel(sch);
} while (ret == -EBUSY);
out_unlock:
spin_unlock_irq(sch->lock);
return ret;
}
/*
* Sysfs interfaces
*/
static ssize_t chpids_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct subchannel *sch = to_subchannel(dev);
struct chsc_ssd_info *ssd = &sch->ssd_info;
ssize_t ret = 0;
int chp;
int mask;
for (chp = 0; chp < 8; chp++) {
mask = 0x80 >> chp;
if (ssd->path_mask & mask)
ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
else
ret += sprintf(buf + ret, "00 ");
}
ret += sprintf(buf+ret, "\n");
return ret;
}
static ssize_t pimpampom_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct subchannel *sch = to_subchannel(dev);
struct pmcw *pmcw = &sch->schib.pmcw;
return sprintf(buf, "%02x %02x %02x\n",
pmcw->pim, pmcw->pam, pmcw->pom);
}
static DEVICE_ATTR(chpids, 0444, chpids_show, NULL);
static DEVICE_ATTR(pimpampom, 0444, pimpampom_show, NULL);
static struct attribute *vfio_subchannel_attrs[] = {
&dev_attr_chpids.attr,
&dev_attr_pimpampom.attr,
NULL,
};
static struct attribute_group vfio_subchannel_attr_group = {
.attrs = vfio_subchannel_attrs,
};
/*
* Css driver callbacks
*/
static void vfio_ccw_sch_irq(struct subchannel *sch)
{
struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
inc_irq_stat(IRQIO_CIO);
if (!private)
return;
if (private->completion)
complete(private->completion);
}
static int vfio_ccw_sch_probe(struct subchannel *sch)
{
struct pmcw *pmcw = &sch->schib.pmcw;
struct vfio_ccw_private *private;
int ret;
if (pmcw->qf) {
dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
dev_name(&sch->dev));
return -ENODEV;
}
private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
if (!private)
return -ENOMEM;
private->sch = sch;
dev_set_drvdata(&sch->dev, private);
spin_lock_irq(sch->lock);
sch->isc = VFIO_CCW_ISC;
ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
spin_unlock_irq(sch->lock);
if (ret)
goto out_free;
ret = sysfs_create_group(&sch->dev.kobj, &vfio_subchannel_attr_group);
if (ret)
goto out_disable;
return 0;
out_disable:
cio_disable_subchannel(sch);
out_free:
dev_set_drvdata(&sch->dev, NULL);
kfree(private);
return ret;
}
static int vfio_ccw_sch_remove(struct subchannel *sch)
{
struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
vfio_ccw_sch_quiesce(sch);
sysfs_remove_group(&sch->dev.kobj, &vfio_subchannel_attr_group);
dev_set_drvdata(&sch->dev, NULL);
kfree(private);
return 0;
}
static void vfio_ccw_sch_shutdown(struct subchannel *sch)
{
vfio_ccw_sch_quiesce(sch);
}
/**
* 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)
{
unsigned long flags;
spin_lock_irqsave(sch->lock, flags);
if (!device_is_registered(&sch->dev))
goto out_unlock;
if (work_pending(&sch->todo_work))
goto out_unlock;
if (cio_update_schib(sch)) {
/* Not operational. */
css_sched_sch_todo(sch, SCH_TODO_UNREG);
/*
* TODO:
* Probably we should send the machine check to the guest.
*/
goto out_unlock;
}
out_unlock:
spin_unlock_irqrestore(sch->lock, flags);
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,
};
static int __init vfio_ccw_sch_init(void)
{
int ret;
isc_register(VFIO_CCW_ISC);
ret = css_driver_register(&vfio_ccw_sch_driver);
if (ret)
isc_unregister(VFIO_CCW_ISC);
return ret;
}
static void __exit vfio_ccw_sch_exit(void)
{
css_driver_unregister(&vfio_ccw_sch_driver);
isc_unregister(VFIO_CCW_ISC);
}
module_init(vfio_ccw_sch_init);
module_exit(vfio_ccw_sch_exit);
MODULE_LICENSE("GPL v2");

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@ -0,0 +1,25 @@
/*
* Private stuff for vfio_ccw driver
*
* Copyright IBM Corp. 2017
*
* Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
* Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
*/
#ifndef _VFIO_CCW_PRIVATE_H_
#define _VFIO_CCW_PRIVATE_H_
#include "css.h"
/**
* struct vfio_ccw_private
* @sch: pointer to the subchannel
* @completion: synchronization helper of the I/O completion
*/
struct vfio_ccw_private {
struct subchannel *sch;
struct completion *completion;
} __aligned(8);
#endif