From 75f990aef38e930f8b676562c4d4b02c1f5eccfd Mon Sep 17 00:00:00 2001 From: Yi Liu Date: Fri, 21 Mar 2025 10:19:29 -0700 Subject: [PATCH] iommufd/device: Wrap igroup->hwpt and igroup->device_list into attach struct The igroup->hwpt and igroup->device_list are used to track the hwpt attach of a group in the RID path. While the coming PASID path also needs such tracking. To be prepared, wrap igroup->hwpt and igroup->device_list into attach struct which is allocated per attaching the first device of the group and freed per detaching the last device of the group. Link: https://patch.msgid.link/r/20250321171940.7213-8-yi.l.liu@intel.com Reviewed-by: Jason Gunthorpe Reviewed-by: Lu Baolu Reviewed-by: Nicolin Chen Signed-off-by: Yi Liu Tested-by: Nicolin Chen Signed-off-by: Jason Gunthorpe --- drivers/iommu/iommufd/device.c | 76 ++++++++++++++++++------- drivers/iommu/iommufd/iommufd_private.h | 5 +- 2 files changed, 58 insertions(+), 23 deletions(-) diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index 2cc3c12d301d..6b4764c2d9af 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -17,12 +17,17 @@ MODULE_PARM_DESC( "Allow IOMMUFD to bind to devices even if the platform cannot isolate " "the MSI interrupt window. Enabling this is a security weakness."); +struct iommufd_attach { + struct iommufd_hw_pagetable *hwpt; + struct list_head device_list; +}; + static void iommufd_group_release(struct kref *kref) { struct iommufd_group *igroup = container_of(kref, struct iommufd_group, ref); - WARN_ON(igroup->hwpt || !list_empty(&igroup->device_list)); + WARN_ON(igroup->attach); xa_cmpxchg(&igroup->ictx->groups, iommu_group_id(igroup->group), igroup, NULL, GFP_KERNEL); @@ -89,7 +94,6 @@ static struct iommufd_group *iommufd_get_group(struct iommufd_ctx *ictx, kref_init(&new_igroup->ref); mutex_init(&new_igroup->lock); - INIT_LIST_HEAD(&new_igroup->device_list); new_igroup->sw_msi_start = PHYS_ADDR_MAX; /* group reference moves into new_igroup */ new_igroup->group = group; @@ -333,7 +337,7 @@ static bool iommufd_group_first_attach(struct iommufd_group *igroup, ioasid_t pasid) { lockdep_assert_held(&igroup->lock); - return !igroup->hwpt; + return !igroup->attach; } static int @@ -369,7 +373,7 @@ static bool iommufd_device_is_attached(struct iommufd_device *idev) { struct iommufd_device *cur; - list_for_each_entry(cur, &idev->igroup->device_list, group_item) + list_for_each_entry(cur, &idev->igroup->attach->device_list, group_item) if (cur == idev) return true; return false; @@ -493,19 +497,33 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, struct iommufd_hwpt_paging *hwpt_paging = find_hwpt_paging(hwpt); bool attach_resv = hwpt_paging && pasid == IOMMU_NO_PASID; struct iommufd_group *igroup = idev->igroup; + struct iommufd_hw_pagetable *old_hwpt; + struct iommufd_attach *attach; int rc; mutex_lock(&igroup->lock); - if (igroup->hwpt && igroup->hwpt != hwpt) { + attach = igroup->attach; + if (!attach) { + attach = kzalloc(sizeof(*attach), GFP_KERNEL); + if (!attach) { + rc = -ENOMEM; + goto err_unlock; + } + INIT_LIST_HEAD(&attach->device_list); + } + + old_hwpt = attach->hwpt; + + if (old_hwpt && old_hwpt != hwpt) { rc = -EINVAL; - goto err_unlock; + goto err_free_attach; } if (attach_resv) { rc = iommufd_device_attach_reserved_iova(idev, hwpt_paging); if (rc) - goto err_unlock; + goto err_free_attach; } /* @@ -519,15 +537,19 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, rc = iommufd_hwpt_attach_device(hwpt, idev, pasid); if (rc) goto err_unresv; - igroup->hwpt = hwpt; + attach->hwpt = hwpt; + igroup->attach = attach; } refcount_inc(&hwpt->obj.users); - list_add_tail(&idev->group_item, &igroup->device_list); + list_add_tail(&idev->group_item, &attach->device_list); mutex_unlock(&igroup->lock); return 0; err_unresv: if (attach_resv) iopt_remove_reserved_iova(&hwpt_paging->ioas->iopt, idev->dev); +err_free_attach: + if (iommufd_group_first_attach(igroup, pasid)) + kfree(attach); err_unlock: mutex_unlock(&igroup->lock); return rc; @@ -537,14 +559,20 @@ struct iommufd_hw_pagetable * iommufd_hw_pagetable_detach(struct iommufd_device *idev, ioasid_t pasid) { struct iommufd_group *igroup = idev->igroup; - struct iommufd_hw_pagetable *hwpt = igroup->hwpt; - struct iommufd_hwpt_paging *hwpt_paging = find_hwpt_paging(hwpt); + struct iommufd_hwpt_paging *hwpt_paging; + struct iommufd_hw_pagetable *hwpt; + struct iommufd_attach *attach; mutex_lock(&igroup->lock); + attach = igroup->attach; + hwpt = attach->hwpt; + hwpt_paging = find_hwpt_paging(hwpt); + list_del(&idev->group_item); - if (list_empty(&igroup->device_list)) { + if (list_empty(&attach->device_list)) { iommufd_hwpt_detach_device(hwpt, idev, pasid); - igroup->hwpt = NULL; + igroup->attach = NULL; + kfree(attach); } if (hwpt_paging && pasid == IOMMU_NO_PASID) iopt_remove_reserved_iova(&hwpt_paging->ioas->iopt, idev->dev); @@ -574,7 +602,7 @@ iommufd_group_remove_reserved_iova(struct iommufd_group *igroup, lockdep_assert_held(&igroup->lock); - list_for_each_entry(cur, &igroup->device_list, group_item) + list_for_each_entry(cur, &igroup->attach->device_list, group_item) iopt_remove_reserved_iova(&hwpt_paging->ioas->iopt, cur->dev); } @@ -588,9 +616,10 @@ iommufd_group_do_replace_reserved_iova(struct iommufd_group *igroup, lockdep_assert_held(&igroup->lock); - old_hwpt_paging = find_hwpt_paging(igroup->hwpt); + old_hwpt_paging = find_hwpt_paging(igroup->attach->hwpt); if (!old_hwpt_paging || hwpt_paging->ioas != old_hwpt_paging->ioas) { - list_for_each_entry(cur, &igroup->device_list, group_item) { + list_for_each_entry(cur, + &igroup->attach->device_list, group_item) { rc = iopt_table_enforce_dev_resv_regions( &hwpt_paging->ioas->iopt, cur->dev, NULL); if (rc) @@ -617,27 +646,32 @@ iommufd_device_do_replace(struct iommufd_device *idev, ioasid_t pasid, struct iommufd_hwpt_paging *old_hwpt_paging; struct iommufd_group *igroup = idev->igroup; struct iommufd_hw_pagetable *old_hwpt; + struct iommufd_attach *attach; unsigned int num_devices; int rc; mutex_lock(&igroup->lock); - if (igroup->hwpt == NULL) { + attach = igroup->attach; + if (!attach) { rc = -EINVAL; goto err_unlock; } + old_hwpt = attach->hwpt; + + WARN_ON(!old_hwpt || list_empty(&attach->device_list)); + if (!iommufd_device_is_attached(idev)) { rc = -EINVAL; goto err_unlock; } - if (hwpt == igroup->hwpt) { + if (hwpt == old_hwpt) { mutex_unlock(&igroup->lock); return NULL; } - old_hwpt = igroup->hwpt; if (attach_resv) { rc = iommufd_group_do_replace_reserved_iova(igroup, hwpt_paging); if (rc) @@ -653,9 +687,9 @@ iommufd_device_do_replace(struct iommufd_device *idev, ioasid_t pasid, (!hwpt_paging || hwpt_paging->ioas != old_hwpt_paging->ioas)) iommufd_group_remove_reserved_iova(igroup, old_hwpt_paging); - igroup->hwpt = hwpt; + attach->hwpt = hwpt; - num_devices = list_count_nodes(&igroup->device_list); + num_devices = list_count_nodes(&attach->device_list); /* * Move the refcounts held by the device_list to the new hwpt. Retain a * refcount for this thread as the caller will free it. diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index 891800948d1a..5b4d8962166b 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -399,13 +399,14 @@ static inline void iommufd_hw_pagetable_put(struct iommufd_ctx *ictx, refcount_dec(&hwpt->obj.users); } +struct iommufd_attach; + struct iommufd_group { struct kref ref; struct mutex lock; struct iommufd_ctx *ictx; struct iommu_group *group; - struct iommufd_hw_pagetable *hwpt; - struct list_head device_list; + struct iommufd_attach *attach; struct iommufd_sw_msi_maps required_sw_msi; phys_addr_t sw_msi_start; }; -- 2.25.1