Introduce VFIO_DEVICE_RESET ioctl for vfio-ccw to make it possible
to hot-reset the device.
We try to achieve a reset by first disabling the subchannel and
then enabling it again: this should clear all state at the subchannel.
Signed-off-by: Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx>
---
drivers/s390/cio/vfio_ccw_ops.c | 42 +++++++++++++++++++++++++++++------------
1 file changed, 30 insertions(+), 12 deletions(-)
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 5c60cda..b702735 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -19,6 +19,31 @@
#define MAX_INSTANCES 1
static int available_instances = MAX_INSTANCES;
+static int vfio_ccw_mdev_reset(struct mdev_device *mdev)
+{
+ struct vfio_ccw_private *private = dev_get_drvdata(mdev->dev.parent);
+ struct subchannel *sch;
+ int ret;
+
+ if (!private)
+ return -ENODEV;
+
+ sch = private->sch;
+ /*
+ * TODO:
+ * In the cureent stage, some things like "no I/O running" and "no
+ * interrupt pending" are clear, but we are not sure what other state
+ * we need to care about.
+ * There are still a lot more instructions need to be handled. We
+ * should come back here later.
+ */
+ ret = vfio_ccw_sch_quiesce(sch);
+ if (ret)
+ return ret;
+
+ return cio_enable_subchannel(sch, (u32)(unsigned long)sch);
+}
+
static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
unsigned long action,
void *data)
@@ -35,15 +60,11 @@ static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
*/
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))
+ if (vfio_ccw_mdev_reset(private->mdev))
return NOTIFY_BAD;
cp_free(&private->cp);
@@ -107,14 +128,9 @@ static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
static int vfio_ccw_mdev_remove(struct mdev_device *mdev)
{
struct vfio_ccw_private *private = dev_get_drvdata(mdev->parent->dev);
- struct subchannel *sch;
int ret;
- sch = private->sch;
- ret = vfio_ccw_sch_quiesce(sch);
- if (ret)
- return ret;
- ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
+ ret = vfio_ccw_mdev_reset(mdev);
if (ret)
return ret;
@@ -193,7 +209,7 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
static int vfio_ccw_mdev_get_device_info(struct mdev_device *mdev,
struct vfio_device_info *info)
{
- info->flags = VFIO_DEVICE_FLAGS_CCW;
+ info->flags = VFIO_DEVICE_FLAGS_CCW | VFIO_DEVICE_FLAGS_RESET;
info->num_regions = VFIO_CCW_NUM_REGIONS;
info->num_irqs = 0;
@@ -265,6 +281,8 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
return copy_to_user((void __user *)arg, &info, minsz);
}
+ case VFIO_DEVICE_RESET:
+ return vfio_ccw_mdev_reset(mdev);
default:
return -ENOTTY;
}
--
2.8.4
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