[PATCH RFC v2 08/15] vfio: ccw: handle ccw command request

Dong Jia Shi
2017-01-12T07:19:40Z

We implement the basic ccw command handling infrastructure
here:
1. Translate the ccw commands.
2. Issue the translated ccw commands to the device.
3. Once we get the execution result, update the guest SCSW
with it.

Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Acked-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
---
drivers/s390/cio/vfio_ccw_drv.c | 115 ++++++++++++++++++++++++++++++++++++
drivers/s390/cio/vfio_ccw_ops.c | 24 ++++++--
drivers/s390/cio/vfio_ccw_private.h | 14 +++++
3 files changed, 149 insertions(+), 4 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index ef34b15..595dcb4 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -15,9 +15,13 @@
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
+#include <linux/uuid.h>
+#include <linux/mdev.h>

#include <asm/isc.h>

+#include "ioasm.h"
+#include "css.h"
#include "vfio_ccw_private.h"

/*
@@ -63,6 +67,109 @@ int vfio_ccw_sch_quiesce(struct subchannel *sch)
return ret;
}

+static int doing_io(struct vfio_ccw_private *private, u32 intparm)
+{
+ return (private->intparm == intparm);
+}
+
+static int vfio_ccw_sch_io_helper(struct vfio_ccw_private *private)
+{
+ struct subchannel *sch;
+ union orb *orb;
+ int ccode;
+ __u8 lpm;
+ u32 intparm;
+
+ sch = private->sch;
+
+ orb = cp_get_orb(&private->cp, (u32)(addr_t)sch, sch->lpm);
+
+ /* Issue "Start Subchannel" */
+ ccode = ssch(sch->schid, orb);
+
+ switch (ccode) {
+ case 0:
+ /*
+ * Initialize device status information
+ */
+ sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND;
+ break;
+ case 1: /* Status pending */
+ case 2: /* Busy */
+ return -EBUSY;
+ 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))
+ return -ENODEV;
+
+ return sch->lpm ? -EACCES : -ENODEV;
+ }
+ default:
+ return ccode;
+ }
+
+ intparm = (u32)(addr_t)sch;
+ private->intparm = 0;
+ wait_event(private->wait_q, doing_io(private, intparm));
+
+ if (scsw_is_solicited(&private->irb.scsw))
+ cp_update_scsw(&private->cp, &private->irb.scsw);
+
+ return 0;
+}
+
+/* Deal with the ccw command request from the userspace. */
+int vfio_ccw_sch_cmd_request(struct vfio_ccw_private *private)
+{
+ struct mdev_device *mdev = private->mdev;
+ union orb *orb;
+ union scsw *scsw = &private->scsw;
+ struct irb *irb = &private->irb;
+ struct ccw_io_region *io_region = &private->io_region;
+ int ret;
+
+ memcpy(scsw, io_region->scsw_area, sizeof(*scsw));
+
+ if (scsw->cmd.fctl & SCSW_FCTL_START_FUNC) {
+ orb = (union orb *)io_region->orb_area;
+
+ ret = cp_init(&private->cp, &mdev->dev, orb);
+ if (ret)
+ return ret;
+
+ ret = cp_prefetch(&private->cp);
+ if (ret) {
+ cp_free(&private->cp);
+ return ret;
+ }
+
+ /* Start channel program and wait for I/O interrupt. */
+ ret = vfio_ccw_sch_io_helper(private);
+ if (!ret) {
+ /* Get irb info and copy it to irb_area. */
+ memcpy(io_region->irb_area, irb, sizeof(*irb));
+ }
+
+ cp_free(&private->cp);
+ } else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
+ /* XXX: Handle halt. */
+ ret = -EOPNOTSUPP;
+ } else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
+ /* XXX: Handle clear. */
+ ret = -EOPNOTSUPP;
+ } else {
+ ret = -EOPNOTSUPP;
+ }
+
+ return ret;
+}
+
/*
* Sysfs interfaces
*/
@@ -117,12 +224,18 @@ static struct attribute_group vfio_subchannel_attr_group = {
static void vfio_ccw_sch_irq(struct subchannel *sch)
{
struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
+ struct irb *irb;

inc_irq_stat(IRQIO_CIO);

if (!private)
return;

+ irb = this_cpu_ptr(&cio_irb);
+ memcpy(&private->irb, irb, sizeof(*irb));
+ private->intparm = (u32)(addr_t)sch;
+ wake_up(&private->wait_q);
+
if (private->completion)
complete(private->completion);
}
@@ -160,6 +273,8 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
if (ret)
goto out_rm_group;

+ init_waitqueue_head(&private->wait_q);
+
return 0;

out_rm_group:
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index d68a296..360ba47 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -30,12 +30,25 @@ static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
return NOTIFY_STOP;

/*
- * TODO:
* Vendor drivers MUST unpin pages in response to an
* invalidation.
*/
- if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP)
- return NOTIFY_BAD;
+ if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP) {
+ struct vfio_iommu_type1_dma_unmap *unmap = data;
+ struct subchannel *sch = private->sch;
+
+ if (!cp_iova_pinned(&private->cp, unmap->iova))
+ return NOTIFY_OK;
+
+ if (vfio_ccw_sch_quiesce(sch))
+ return NOTIFY_BAD;
+
+ if (cio_enable_subchannel(sch, (u32)(unsigned long)sch))
+ return NOTIFY_BAD;
+
+ cp_free(&private->cp);
+ return NOTIFY_OK;
+ }

return NOTIFY_DONE;
}
@@ -169,7 +182,10 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
region = &private->io_region;
if (copy_from_user((void *)region + *ppos, buf, count))
return -EFAULT;
- region->ret_code = 0;
+
+ region->ret_code = vfio_ccw_sch_cmd_request(private);
+ if (region->ret_code != 0)
+ return region->ret_code;

return count;
}
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index 99265a9..4621934 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -14,9 +14,11 @@
#ifndef _VFIO_CCW_PRIVATE_H_
#define _VFIO_CCW_PRIVATE_H_

+#include <linux/completion.h>
#include <asm/vfio_ccw.h>

#include "css.h"
+#include "vfio_ccw_cp.h"

/**
* struct vfio_ccw_private
@@ -25,6 +27,11 @@
* @mdev: pointor to the mediated device
* @nb: notifier for vfio events
* @io_region: MMIO region to input/output I/O arguments/results
+ * @wait_q: wait for interrupt
+ * @intparm: record current interrupt parameter, used for wait interrupt
+ * @cp: ccw program for the current I/O operation
+ * @irb: irb info received from interrupt
+ * @scsw: scsw info
*/
struct vfio_ccw_private {
struct subchannel *sch;
@@ -32,11 +39,18 @@ struct vfio_ccw_private {
struct mdev_device *mdev;
struct notifier_block nb;
struct ccw_io_region io_region;
+
+ wait_queue_head_t wait_q;
+ u32 intparm;
+ struct ccwprogram cp;
+ struct irb irb;
+ union scsw scsw;
} __aligned(8);

extern int vfio_ccw_mdev_reg(struct subchannel *sch);
extern void vfio_ccw_mdev_unreg(struct subchannel *sch);

extern int vfio_ccw_sch_quiesce(struct subchannel *sch);
+extern int vfio_ccw_sch_cmd_request(struct vfio_ccw_private *private);

#endif
--
2.8.4