From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dong Jia Shi Subject: [PATCH RFC v2 10/15] vfio: ccw: realize VFIO_DEVICE_RESET ioctl Date: Thu, 12 Jan 2017 08:19:42 +0100 Message-ID: <20170112071947.98071-11-bjsdjshi@linux.vnet.ibm.com> References: <20170112071947.98071-1-bjsdjshi@linux.vnet.ibm.com> Return-path: In-Reply-To: <20170112071947.98071-1-bjsdjshi@linux.vnet.ibm.com> Sender: kvm-owner@vger.kernel.org List-Archive: List-Post: To: kvm@vger.kernel.org, linux-s390@vger.kernel.org, qemu-devel@nongnu.org Cc: bjsdjshi@linux.vnet.ibm.com, renxiaof@linux.vnet.ibm.com, cornelia.huck@de.ibm.com, borntraeger@de.ibm.com, agraf@suse.com, alex.williamson@redhat.com, pmorel@linux.vnet.ibm.com, pasic@linux.vnet.ibm.com, wkywang@linux.vnet.ibm.com List-ID: 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 --- 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