[RFC PATCH 1/3] vfio: ccw: introduce schib region

Dong Jia Shi
2018-01-11T03:04:19Z

This introduces a new region for vfio-ccw to provide subchannel
information for user space.

Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
---
drivers/s390/cio/vfio_ccw_fsm.c | 21 ++++++++++
drivers/s390/cio/vfio_ccw_ops.c | 79 +++++++++++++++++++++++++++----------
drivers/s390/cio/vfio_ccw_private.h | 3 ++
include/uapi/linux/vfio.h | 1 +
include/uapi/linux/vfio_ccw.h | 6 +++
5 files changed, 90 insertions(+), 20 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index c30420c517b1..be081ccabea3 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -172,6 +172,22 @@ static void fsm_irq(struct vfio_ccw_private *private,
complete(private->completion);
}

+static void fsm_update_subch(struct vfio_ccw_private *private,
+ enum vfio_ccw_event event)
+{
+ struct subchannel *sch;
+
+ sch = private->sch;
+ if (cio_update_schib(sch)) {
+ private->schib_region.cc = 3;
+ return;
+ }
+
+ private->schib_region.cc = 0;
+ memcpy(private->schib_region.schib_area, &sch->schib,
+ sizeof(sch->schib));
+}
+
/*
* Device statemachine
*/
@@ -180,25 +196,30 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_nop,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq,
+ [VFIO_CCW_EVENT_UPDATE_SUBCH] = fsm_update_subch,
},
[VFIO_CCW_STATE_STANDBY] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
+ [VFIO_CCW_EVENT_UPDATE_SUBCH] = fsm_update_subch,
},
[VFIO_CCW_STATE_IDLE] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_request,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
+ [VFIO_CCW_EVENT_UPDATE_SUBCH] = fsm_update_subch,
},
[VFIO_CCW_STATE_BOXED] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
+ [VFIO_CCW_EVENT_UPDATE_SUBCH] = fsm_update_subch,
},
[VFIO_CCW_STATE_BUSY] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
+ [VFIO_CCW_EVENT_UPDATE_SUBCH] = fsm_update_subch,
},
};
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 41eeb57d68a3..9528fce2e7d9 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -13,6 +13,11 @@

#include "vfio_ccw_private.h"

+#define VFIO_CCW_OFFSET_SHIFT 40
+#define VFIO_CCW_OFFSET_TO_INDEX(off) (off >> VFIO_CCW_OFFSET_SHIFT)
+#define VFIO_CCW_INDEX_TO_OFFSET(index) ((u64)(index) << VFIO_CCW_OFFSET_SHIFT)
+#define VFIO_CCW_OFFSET_MASK (((u64)(1) << VFIO_CCW_OFFSET_SHIFT) - 1)
+
static int vfio_ccw_mdev_reset(struct mdev_device *mdev)
{
struct vfio_ccw_private *private;
@@ -168,14 +173,31 @@ static ssize_t vfio_ccw_mdev_read(struct mdev_device *mdev,
loff_t *ppos)
{
struct vfio_ccw_private *private;
- struct ccw_io_region *region;
+ void *region;
+ u32 index;
+ loff_t pos;
+
+ index = VFIO_CCW_OFFSET_TO_INDEX(*ppos);
+ pos = (*ppos) & VFIO_CCW_OFFSET_MASK;
+ private = dev_get_drvdata(mdev_parent_dev(mdev));

- if (*ppos + count > sizeof(*region))
+ switch (index) {
+ case VFIO_CCW_CONFIG_REGION_INDEX:
+ if (pos + count > sizeof(struct ccw_io_region))
+ return -EINVAL;
+ region = &private->io_region;
+ break;
+ case VFIO_CCW_SCHIB_REGION_INDEX:
+ if (pos + count > sizeof(struct ccw_schib_region))
+ return -EINVAL;
+ region = &private->schib_region;
+ vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_UPDATE_SUBCH);
+ break;
+ default:
return -EINVAL;
+ }

- private = dev_get_drvdata(mdev_parent_dev(mdev));
- region = &private->io_region;
- if (copy_to_user(buf, (void *)region + *ppos, count))
+ if (copy_to_user(buf, region + pos, count))
return -EFAULT;

return count;
@@ -187,23 +209,35 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
loff_t *ppos)
{
struct vfio_ccw_private *private;
- struct ccw_io_region *region;
-
- if (*ppos + count > sizeof(*region))
- return -EINVAL;
+ u32 index;
+ loff_t pos;

+ index = VFIO_CCW_OFFSET_TO_INDEX(*ppos);
+ pos = (*ppos) & VFIO_CCW_OFFSET_MASK;
private = dev_get_drvdata(mdev_parent_dev(mdev));
- if (private->state != VFIO_CCW_STATE_IDLE)
- return -EACCES;

- region = &private->io_region;
- if (copy_from_user((void *)region + *ppos, buf, count))
- return -EFAULT;
-
- vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_IO_REQ);
- if (region->ret_code != 0) {
- private->state = VFIO_CCW_STATE_IDLE;
- return region->ret_code;
+ switch (index) {
+ case VFIO_CCW_CONFIG_REGION_INDEX:
+ {
+ struct ccw_io_region *region;
+ if (pos + count > sizeof(*region))
+ return -EINVAL;
+ if (private->state != VFIO_CCW_STATE_IDLE)
+ return -EACCES;
+ region = &private->io_region;
+ if (copy_from_user((void *)region + *ppos, buf, count))
+ return -EFAULT;
+ vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_IO_REQ);
+ if (region->ret_code != 0) {
+ private->state = VFIO_CCW_STATE_IDLE;
+ return region->ret_code;
+ }
+ break;
+ }
+ case VFIO_CCW_SCHIB_REGION_INDEX:
+ return -EOPNOTSUPP;
+ default:
+ return -EINVAL;
}

return count;
@@ -224,11 +258,16 @@ static int vfio_ccw_mdev_get_region_info(struct vfio_region_info *info,
{
switch (info->index) {
case VFIO_CCW_CONFIG_REGION_INDEX:
- info->offset = 0;
+ info->offset = VFIO_CCW_INDEX_TO_OFFSET(info->index);
info->size = sizeof(struct ccw_io_region);
info->flags = VFIO_REGION_INFO_FLAG_READ
| VFIO_REGION_INFO_FLAG_WRITE;
return 0;
+ case VFIO_CCW_SCHIB_REGION_INDEX:
+ info->offset = VFIO_CCW_INDEX_TO_OFFSET(info->index);
+ info->size = sizeof(struct ccw_schib_region);
+ info->flags = VFIO_REGION_INFO_FLAG_READ;
+ return 0;
default:
return -EINVAL;
}
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index 78a66d96756b..460c8b90d834 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -28,6 +28,7 @@
* @mdev: pointer to the mediated device
* @nb: notifier for vfio events
* @io_region: MMIO region to input/output I/O arguments/results
+ * @schib_region: MMIO region of subchannel information
* @cp: channel program for the current I/O operation
* @irb: irb info received from interrupt
* @scsw: scsw info
@@ -42,6 +43,7 @@ struct vfio_ccw_private {
struct mdev_device *mdev;
struct notifier_block nb;
struct ccw_io_region io_region;
+ struct ccw_schib_region schib_region;

struct channel_program cp;
struct irb irb;
@@ -76,6 +78,7 @@ enum vfio_ccw_event {
VFIO_CCW_EVENT_NOT_OPER,
VFIO_CCW_EVENT_IO_REQ,
VFIO_CCW_EVENT_INTERRUPT,
+ VFIO_CCW_EVENT_UPDATE_SUBCH,
/* last element! */
NR_VFIO_CCW_EVENTS
};
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index e3301dbd27d4..c60244debf71 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -457,6 +457,7 @@ enum {

enum {
VFIO_CCW_CONFIG_REGION_INDEX,
+ VFIO_CCW_SCHIB_REGION_INDEX,
VFIO_CCW_NUM_REGIONS
};

diff --git a/include/uapi/linux/vfio_ccw.h b/include/uapi/linux/vfio_ccw.h
index 2ec5f367ff78..12508ef6e6fc 100644
--- a/include/uapi/linux/vfio_ccw.h
+++ b/include/uapi/linux/vfio_ccw.h
@@ -22,4 +22,10 @@ struct ccw_io_region {
__u32 ret_code;
} __packed;

+struct ccw_schib_region {
+ __u8 cc;
+#define SCHIB_AREA_SIZE 52
+ __u8 schib_area[SCHIB_AREA_SIZE];
+} __packed;
+
#endif
--
2.13.5