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
Cornelia Huck
parent
aec390b937
commit
63f1934d56
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@ -672,6 +672,16 @@ config EADM_SCH
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To compile this driver as a module, choose M here: the
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module will be called eadm_sch.
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config VFIO_CCW
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def_tristate n
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prompt "Support for VFIO-CCW subchannels"
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depends on S390_CCW_IOMMU && VFIO
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help
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This driver allows usage of I/O subchannels via VFIO-CCW.
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To compile this driver as a module, choose M here: the
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module will be called vfio_ccw.
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endmenu
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menu "Dump support"
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@ -16,6 +16,7 @@
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#define CONSOLE_ISC 1 /* console I/O subchannel */
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#define EADM_SCH_ISC 4 /* EADM subchannels */
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#define CHSC_SCH_ISC 7 /* CHSC subchannels */
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#define VFIO_CCW_ISC IO_SCH_ISC /* VFIO-CCW I/O subchannels */
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/* Adapter interrupts. */
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#define QDIO_AIRQ_ISC IO_SCH_ISC /* I/O subchannel in qdio mode */
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#define PCI_ISC 2 /* PCI I/O subchannels */
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@ -327,6 +327,14 @@ config S390_IOMMU
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help
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Support for the IOMMU API for s390 PCI devices.
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config S390_CCW_IOMMU
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bool "S390 CCW IOMMU Support"
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depends on S390 && CCW
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select IOMMU_API
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help
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Enables bits of IOMMU API required by VFIO. The iommu_ops
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is not implemented as it is not necessary for VFIO.
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config MTK_IOMMU
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bool "MTK IOMMU Support"
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depends on ARM || ARM64
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@ -17,3 +17,6 @@ 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
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obj-$(CONFIG_VFIO_CCW) += vfio_ccw.o
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@ -0,0 +1,262 @@
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/*
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* VFIO based Physical Subchannel device driver
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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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* Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/slab.h>
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#include <asm/isc.h>
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#include "vfio_ccw_private.h"
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/*
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* Helpers
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*/
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static int vfio_ccw_sch_quiesce(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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DECLARE_COMPLETION_ONSTACK(completion);
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int iretry, ret = 0;
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spin_lock_irq(sch->lock);
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if (!sch->schib.pmcw.ena)
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goto out_unlock;
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ret = cio_disable_subchannel(sch);
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if (ret != -EBUSY)
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goto out_unlock;
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do {
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iretry = 255;
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ret = cio_cancel_halt_clear(sch, &iretry);
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while (ret == -EBUSY) {
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/*
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* Flush all I/O and wait for
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* cancel/halt/clear completion.
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*/
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private->completion = &completion;
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spin_unlock_irq(sch->lock);
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wait_for_completion_timeout(&completion, 3*HZ);
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spin_lock_irq(sch->lock);
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private->completion = NULL;
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ret = cio_cancel_halt_clear(sch, &iretry);
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};
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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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spin_unlock_irq(sch->lock);
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return ret;
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}
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/*
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* Sysfs interfaces
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*/
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static ssize_t chpids_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct subchannel *sch = to_subchannel(dev);
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struct chsc_ssd_info *ssd = &sch->ssd_info;
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ssize_t ret = 0;
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int chp;
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int mask;
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for (chp = 0; chp < 8; chp++) {
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mask = 0x80 >> chp;
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if (ssd->path_mask & mask)
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ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
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else
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ret += sprintf(buf + ret, "00 ");
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}
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ret += sprintf(buf+ret, "\n");
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return ret;
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}
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static ssize_t pimpampom_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct subchannel *sch = to_subchannel(dev);
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struct pmcw *pmcw = &sch->schib.pmcw;
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return sprintf(buf, "%02x %02x %02x\n",
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pmcw->pim, pmcw->pam, pmcw->pom);
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}
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static DEVICE_ATTR(chpids, 0444, chpids_show, NULL);
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static DEVICE_ATTR(pimpampom, 0444, pimpampom_show, NULL);
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static struct attribute *vfio_subchannel_attrs[] = {
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&dev_attr_chpids.attr,
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&dev_attr_pimpampom.attr,
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NULL,
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};
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static struct attribute_group vfio_subchannel_attr_group = {
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.attrs = vfio_subchannel_attrs,
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};
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/*
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* Css driver callbacks
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*/
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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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inc_irq_stat(IRQIO_CIO);
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if (!private)
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return;
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if (private->completion)
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complete(private->completion);
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}
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static int vfio_ccw_sch_probe(struct subchannel *sch)
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{
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struct pmcw *pmcw = &sch->schib.pmcw;
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struct vfio_ccw_private *private;
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int ret;
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if (pmcw->qf) {
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dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
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dev_name(&sch->dev));
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return -ENODEV;
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}
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private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
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if (!private)
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return -ENOMEM;
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private->sch = sch;
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dev_set_drvdata(&sch->dev, private);
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spin_lock_irq(sch->lock);
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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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if (ret)
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goto out_free;
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ret = sysfs_create_group(&sch->dev.kobj, &vfio_subchannel_attr_group);
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if (ret)
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goto out_disable;
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return 0;
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out_disable:
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cio_disable_subchannel(sch);
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out_free:
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dev_set_drvdata(&sch->dev, NULL);
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kfree(private);
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return ret;
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}
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static int vfio_ccw_sch_remove(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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vfio_ccw_sch_quiesce(sch);
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sysfs_remove_group(&sch->dev.kobj, &vfio_subchannel_attr_group);
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dev_set_drvdata(&sch->dev, NULL);
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kfree(private);
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return 0;
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}
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static void vfio_ccw_sch_shutdown(struct subchannel *sch)
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{
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vfio_ccw_sch_quiesce(sch);
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}
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/**
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* vfio_ccw_sch_event - process subchannel event
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* @sch: subchannel
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* @process: non-zero if function is called in process context
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*
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* An unspecified event occurred for this subchannel. Adjust data according
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* to the current operational state of the subchannel. Return zero when the
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* event has been handled sufficiently or -EAGAIN when this function should
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* be called again in process context.
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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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unsigned long flags;
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spin_lock_irqsave(sch->lock, flags);
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if (!device_is_registered(&sch->dev))
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goto out_unlock;
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if (work_pending(&sch->todo_work))
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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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goto out_unlock;
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}
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out_unlock:
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spin_unlock_irqrestore(sch->lock, flags);
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return 0;
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}
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static struct css_device_id vfio_ccw_sch_ids[] = {
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{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
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{ /* end of list */ },
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};
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MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
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static struct css_driver vfio_ccw_sch_driver = {
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.drv = {
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.name = "vfio_ccw",
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.owner = THIS_MODULE,
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},
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.subchannel_type = vfio_ccw_sch_ids,
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.irq = vfio_ccw_sch_irq,
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.probe = vfio_ccw_sch_probe,
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.remove = vfio_ccw_sch_remove,
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.shutdown = vfio_ccw_sch_shutdown,
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.sch_event = vfio_ccw_sch_event,
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};
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static int __init vfio_ccw_sch_init(void)
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{
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int ret;
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isc_register(VFIO_CCW_ISC);
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ret = css_driver_register(&vfio_ccw_sch_driver);
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if (ret)
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isc_unregister(VFIO_CCW_ISC);
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return ret;
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}
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static void __exit vfio_ccw_sch_exit(void)
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{
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css_driver_unregister(&vfio_ccw_sch_driver);
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isc_unregister(VFIO_CCW_ISC);
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}
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module_init(vfio_ccw_sch_init);
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module_exit(vfio_ccw_sch_exit);
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MODULE_LICENSE("GPL v2");
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@ -0,0 +1,25 @@
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/*
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* Private stuff for vfio_ccw driver
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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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* Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
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*/
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#ifndef _VFIO_CCW_PRIVATE_H_
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#define _VFIO_CCW_PRIVATE_H_
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#include "css.h"
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/**
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* struct vfio_ccw_private
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* @sch: pointer to the subchannel
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* @completion: synchronization helper of the I/O completion
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*/
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struct vfio_ccw_private {
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struct subchannel *sch;
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struct completion *completion;
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} __aligned(8);
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#endif
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