[RFC PATCH v1 08/10] vfio-ccw: Wire up the CRW irq and CRW region

[Eric Farman <farman@xxxxxxxxxxxxx>]

From: Farhan Ali <alifm@xxxxxxxxxxxxx>

Use an IRQ to notify userspace that there is a CRW
pending in the region, related to path-availability
changes on the passthrough subchannel.

Signed-off-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx>
---

Notes:
    v0->v1: [EF]
     - Place the non-refactoring changes from the previous patch here
     - Clean up checkpatch (whitespace) errors
     - s/chp_crw/crw/
     - Move acquire/release of io_mutex in vfio_ccw_crw_region_read()
       into patch that introduces that region
     - Remove duplicate include from vfio_ccw_drv.c
     - Reorder include in vfio_ccw_private.h

 drivers/s390/cio/vfio_ccw_drv.c     | 27 +++++++++++++++++++++++++++
 drivers/s390/cio/vfio_ccw_ops.c     |  4 ++++
 drivers/s390/cio/vfio_ccw_private.h |  4 ++++
 include/uapi/linux/vfio.h           |  1 +
 4 files changed, 36 insertions(+)

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index d1b9020d037b..ab20c32e5319 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -108,6 +108,22 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work)
 		eventfd_signal(private->io_trigger, 1);
 }
 
+static void vfio_ccw_crw_todo(struct work_struct *work)
+{
+	struct vfio_ccw_private *private;
+	struct crw *crw;
+
+	private = container_of(work, struct vfio_ccw_private, crw_work);
+	crw = &private->crw;
+
+	mutex_lock(&private->io_mutex);
+	memcpy(&private->crw_region->crw0, crw, sizeof(*crw));
+	mutex_unlock(&private->io_mutex);
+
+	if (private->crw_trigger)
+		eventfd_signal(private->crw_trigger, 1);
+}
+
 /*
  * Css driver callbacks
  */
@@ -187,6 +203,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
 		goto out_free;
 
 	INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
+	INIT_WORK(&private->crw_work, vfio_ccw_crw_todo);
 	atomic_set(&private->avail, 1);
 	private->state = VFIO_CCW_STATE_STANDBY;
 
@@ -303,6 +320,11 @@ static int vfio_ccw_chp_event(struct subchannel *sch,
 	case CHP_OFFLINE:
 		/* Path is gone */
 		cio_cancel_halt_clear(sch, &retry);
+		private->crw.rsc = CRW_RSC_CPATH;
+		private->crw.rsid = 0x0 | (link->chpid.cssid << 8) |
+				    link->chpid.id;
+		private->crw.erc = CRW_ERC_PERRN;
+		queue_work(vfio_ccw_work_q, &private->crw_work);
 		break;
 	case CHP_VARY_ON:
 		/* Path logically turned on */
@@ -312,6 +334,11 @@ static int vfio_ccw_chp_event(struct subchannel *sch,
 	case CHP_ONLINE:
 		/* Path became available */
 		sch->lpm |= mask & sch->opm;
+		private->crw.rsc = CRW_RSC_CPATH;
+		private->crw.rsid = 0x0 | (link->chpid.cssid << 8) |
+				    link->chpid.id;
+		private->crw.erc = CRW_ERC_INIT;
+		queue_work(vfio_ccw_work_q, &private->crw_work);
 		break;
 	}
 
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index f3033f8fc96d..8b3ed5b45277 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -393,6 +393,7 @@ static int vfio_ccw_mdev_get_irq_info(struct vfio_irq_info *info)
 {
 	switch (info->index) {
 	case VFIO_CCW_IO_IRQ_INDEX:
+	case VFIO_CCW_CRW_IRQ_INDEX:
 		info->count = 1;
 		info->flags = VFIO_IRQ_INFO_EVENTFD;
 		break;
@@ -420,6 +421,9 @@ static int vfio_ccw_mdev_set_irqs(struct mdev_device *mdev,
 	case VFIO_CCW_IO_IRQ_INDEX:
 		ctx = &private->io_trigger;
 		break;
+	case VFIO_CCW_CRW_IRQ_INDEX:
+		ctx = &private->crw_trigger;
+		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index 8289b6850e59..558c658f3583 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -17,6 +17,7 @@
 #include <linux/eventfd.h>
 #include <linux/workqueue.h>
 #include <linux/vfio_ccw.h>
+#include <asm/crw.h>
 #include <asm/debug.h>
 
 #include "css.h"
@@ -98,9 +99,12 @@ struct vfio_ccw_private {
 	struct channel_program	cp;
 	struct irb		irb;
 	union scsw		scsw;
+	struct crw		crw;
 
 	struct eventfd_ctx	*io_trigger;
+	struct eventfd_ctx	*crw_trigger;
 	struct work_struct	io_work;
+	struct work_struct	crw_work;
 } __aligned(8);
 
 extern int vfio_ccw_mdev_reg(struct subchannel *sch);
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 5024636d7615..1bdf32772545 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -579,6 +579,7 @@ enum {
 
 enum {
 	VFIO_CCW_IO_IRQ_INDEX,
+	VFIO_CCW_CRW_IRQ_INDEX,
 	VFIO_CCW_NUM_IRQS
 };
 
-- 
2.17.1