From 83d1193a96dc78576c15f93cd70e0558763a85b3 Mon Sep 17 00:00:00 2001 From: Dong Jia Shi Date: Fri, 17 Mar 2017 04:17:37 +0100 Subject: vfio: ccw: realize VFIO_DEVICE_RESET ioctl 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 Message-Id: <20170317031743.40128-11-bjsdjshi@linux.vnet.ibm.com> Signed-off-by: Cornelia Huck --- drivers/s390/cio/vfio_ccw_ops.c | 47 +++++++++++++++++++++++++++++------------ 1 file changed, 33 insertions(+), 14 deletions(-) (limited to 'drivers/s390') diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c index f3300ddded3f..125818cdf305 100644 --- a/drivers/s390/cio/vfio_ccw_ops.c +++ b/drivers/s390/cio/vfio_ccw_ops.c @@ -12,6 +12,32 @@ #include "vfio_ccw_private.h" +static int vfio_ccw_mdev_reset(struct mdev_device *mdev) +{ + struct vfio_ccw_private *private; + struct subchannel *sch; + int ret; + + private = dev_get_drvdata(mdev_parent_dev(mdev)); + 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) @@ -28,15 +54,11 @@ 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); @@ -100,16 +122,11 @@ 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; - struct subchannel *sch; + struct vfio_ccw_private *private = + dev_get_drvdata(mdev_parent_dev(mdev)); int ret; - private = dev_get_drvdata(mdev_parent_dev(mdev)); - 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; @@ -190,7 +207,7 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev, static int vfio_ccw_mdev_get_device_info(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; @@ -260,6 +277,8 @@ 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; } -- cgit v1.2.3