From 6caeb33fa986151f745fc62190bc28a593b8a0d2 Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Tue, 10 Jan 2023 10:54:05 +0800 Subject: [PATCH] iommu: Add set_platform_dma_ops iommu ops When VFIO finishes assigning a device to user space and calls iommu_group_release_dma_owner() to return the device to kernel, the IOMMU core will attach the default domain to the device. Unfortunately, some IOMMU drivers don't support default domain, hence in the end, the core calls .detach_dev instead. This adds set_platform_dma_ops iommu ops to make it clear that what it does is returning control back to the platform DMA ops. Suggested-by: Jason Gunthorpe Reviewed-by: Jason Gunthorpe Signed-off-by: Lu Baolu Link: https://lore.kernel.org/r/20230110025408.667767-3-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- drivers/iommu/iommu.c | 28 ++++++++++++++++++++++++---- include/linux/iommu.h | 4 ++++ 2 files changed, 28 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index de91dd8..1c8b2c7 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2163,6 +2163,16 @@ static int iommu_group_do_detach_device(struct device *dev, void *data) return 0; } +static int iommu_group_do_set_platform_dma(struct device *dev, void *data) +{ + const struct iommu_ops *ops = dev_iommu_ops(dev); + + if (!WARN_ON(!ops->set_platform_dma_ops)) + ops->set_platform_dma_ops(dev); + + return 0; +} + static int __iommu_group_set_domain(struct iommu_group *group, struct iommu_domain *new_domain) { @@ -2177,10 +2187,20 @@ static int __iommu_group_set_domain(struct iommu_group *group, * platform specific behavior. */ if (!new_domain) { - if (WARN_ON(!group->domain->ops->detach_dev)) - return -EINVAL; - __iommu_group_for_each_dev(group, group->domain, - iommu_group_do_detach_device); + struct group_device *grp_dev; + + grp_dev = list_first_entry(&group->devices, + struct group_device, list); + + if (dev_iommu_ops(grp_dev->dev)->set_platform_dma_ops) + __iommu_group_for_each_dev(group, NULL, + iommu_group_do_set_platform_dma); + else if (group->domain->ops->detach_dev) + __iommu_group_for_each_dev(group, group->domain, + iommu_group_do_detach_device); + else + WARN_ON_ONCE(1); + group->domain = NULL; return 0; } diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 46e1347..7b3e377 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -228,6 +228,9 @@ struct iommu_iotlb_gather { * @release_device: Remove device from iommu driver handling * @probe_finalize: Do final setup work after the device is added to an IOMMU * group and attached to the groups domain + * @set_platform_dma_ops: Returning control back to the platform DMA ops. This op + * is to support old IOMMU drivers, new drivers should use + * default domains, and the common IOMMU DMA ops. * @device_group: find iommu group for a particular device * @get_resv_regions: Request list of reserved regions for a device * @of_xlate: add OF master IDs to iommu grouping @@ -256,6 +259,7 @@ struct iommu_ops { struct iommu_device *(*probe_device)(struct device *dev); void (*release_device)(struct device *dev); void (*probe_finalize)(struct device *dev); + void (*set_platform_dma_ops)(struct device *dev); struct iommu_group *(*device_group)(struct device *dev); /* Request/Free a list of reserved regions for a device */ -- 2.7.4