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iommu/vt-d: Add cache tag assignment interface
Caching tag is a combination of tags used by the hardware to cache various translations. Whenever a mapping in a domain is changed, the IOMMU driver should invalidate the caches with the caching tags. The VT-d specification describes caching tags in section 6.2.1, Tagging of Cached Translations. Add interface to assign caching tags to an IOMMU domain when attached to a RID or PASID, and unassign caching tags when a domain is detached from a RID or PASID. All caching tags are listed in the per-domain tag list and are protected by a dedicated lock. In addition to the basic IOTLB and devTLB caching tag types, NESTING_IOTLB and NESTING_DEVTLB tag types are also introduced. These tags are used for caches that store translations for DMA accesses through a nested user domain. They are affected by changes to mappings in the parent domain. Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Link: https://lore.kernel.org/r/20240416080656.60968-2-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,214 @@ | ||
| // SPDX-License-Identifier: GPL-2.0 | ||
| /* | ||
| * cache.c - Intel VT-d cache invalidation | ||
| * | ||
| * Copyright (C) 2024 Intel Corporation | ||
| * | ||
| * Author: Lu Baolu <baolu.lu@linux.intel.com> | ||
| */ | ||
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| #define pr_fmt(fmt) "DMAR: " fmt | ||
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| #include <linux/dmar.h> | ||
| #include <linux/iommu.h> | ||
| #include <linux/memory.h> | ||
| #include <linux/spinlock.h> | ||
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| #include "iommu.h" | ||
| #include "pasid.h" | ||
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| /* Check if an existing cache tag can be reused for a new association. */ | ||
| static bool cache_tage_match(struct cache_tag *tag, u16 domain_id, | ||
| struct intel_iommu *iommu, struct device *dev, | ||
| ioasid_t pasid, enum cache_tag_type type) | ||
| { | ||
| if (tag->type != type) | ||
| return false; | ||
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| if (tag->domain_id != domain_id || tag->pasid != pasid) | ||
| return false; | ||
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| if (type == CACHE_TAG_IOTLB || type == CACHE_TAG_NESTING_IOTLB) | ||
| return tag->iommu == iommu; | ||
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| if (type == CACHE_TAG_DEVTLB || type == CACHE_TAG_NESTING_DEVTLB) | ||
| return tag->dev == dev; | ||
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| return false; | ||
| } | ||
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| /* Assign a cache tag with specified type to domain. */ | ||
| static int cache_tag_assign(struct dmar_domain *domain, u16 did, | ||
| struct device *dev, ioasid_t pasid, | ||
| enum cache_tag_type type) | ||
| { | ||
| struct device_domain_info *info = dev_iommu_priv_get(dev); | ||
| struct intel_iommu *iommu = info->iommu; | ||
| struct cache_tag *tag, *temp; | ||
| unsigned long flags; | ||
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| tag = kzalloc(sizeof(*tag), GFP_KERNEL); | ||
| if (!tag) | ||
| return -ENOMEM; | ||
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| tag->type = type; | ||
| tag->iommu = iommu; | ||
| tag->domain_id = did; | ||
| tag->pasid = pasid; | ||
| tag->users = 1; | ||
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| if (type == CACHE_TAG_DEVTLB || type == CACHE_TAG_NESTING_DEVTLB) | ||
| tag->dev = dev; | ||
| else | ||
| tag->dev = iommu->iommu.dev; | ||
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| spin_lock_irqsave(&domain->cache_lock, flags); | ||
| list_for_each_entry(temp, &domain->cache_tags, node) { | ||
| if (cache_tage_match(temp, did, iommu, dev, pasid, type)) { | ||
| temp->users++; | ||
| spin_unlock_irqrestore(&domain->cache_lock, flags); | ||
| kfree(tag); | ||
| return 0; | ||
| } | ||
| } | ||
| list_add_tail(&tag->node, &domain->cache_tags); | ||
| spin_unlock_irqrestore(&domain->cache_lock, flags); | ||
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| return 0; | ||
| } | ||
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| /* Unassign a cache tag with specified type from domain. */ | ||
| static void cache_tag_unassign(struct dmar_domain *domain, u16 did, | ||
| struct device *dev, ioasid_t pasid, | ||
| enum cache_tag_type type) | ||
| { | ||
| struct device_domain_info *info = dev_iommu_priv_get(dev); | ||
| struct intel_iommu *iommu = info->iommu; | ||
| struct cache_tag *tag; | ||
| unsigned long flags; | ||
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| spin_lock_irqsave(&domain->cache_lock, flags); | ||
| list_for_each_entry(tag, &domain->cache_tags, node) { | ||
| if (cache_tage_match(tag, did, iommu, dev, pasid, type)) { | ||
| if (--tag->users == 0) { | ||
| list_del(&tag->node); | ||
| kfree(tag); | ||
| } | ||
| break; | ||
| } | ||
| } | ||
| spin_unlock_irqrestore(&domain->cache_lock, flags); | ||
| } | ||
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| static int __cache_tag_assign_domain(struct dmar_domain *domain, u16 did, | ||
| struct device *dev, ioasid_t pasid) | ||
| { | ||
| struct device_domain_info *info = dev_iommu_priv_get(dev); | ||
| int ret; | ||
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| ret = cache_tag_assign(domain, did, dev, pasid, CACHE_TAG_IOTLB); | ||
| if (ret || !info->ats_enabled) | ||
| return ret; | ||
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| ret = cache_tag_assign(domain, did, dev, pasid, CACHE_TAG_DEVTLB); | ||
| if (ret) | ||
| cache_tag_unassign(domain, did, dev, pasid, CACHE_TAG_IOTLB); | ||
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| return ret; | ||
| } | ||
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| static void __cache_tag_unassign_domain(struct dmar_domain *domain, u16 did, | ||
| struct device *dev, ioasid_t pasid) | ||
| { | ||
| struct device_domain_info *info = dev_iommu_priv_get(dev); | ||
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| cache_tag_unassign(domain, did, dev, pasid, CACHE_TAG_IOTLB); | ||
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| if (info->ats_enabled) | ||
| cache_tag_unassign(domain, did, dev, pasid, CACHE_TAG_DEVTLB); | ||
| } | ||
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| static int __cache_tag_assign_parent_domain(struct dmar_domain *domain, u16 did, | ||
| struct device *dev, ioasid_t pasid) | ||
| { | ||
| struct device_domain_info *info = dev_iommu_priv_get(dev); | ||
| int ret; | ||
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| ret = cache_tag_assign(domain, did, dev, pasid, CACHE_TAG_NESTING_IOTLB); | ||
| if (ret || !info->ats_enabled) | ||
| return ret; | ||
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| ret = cache_tag_assign(domain, did, dev, pasid, CACHE_TAG_NESTING_DEVTLB); | ||
| if (ret) | ||
| cache_tag_unassign(domain, did, dev, pasid, CACHE_TAG_NESTING_IOTLB); | ||
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| return ret; | ||
| } | ||
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| static void __cache_tag_unassign_parent_domain(struct dmar_domain *domain, u16 did, | ||
| struct device *dev, ioasid_t pasid) | ||
| { | ||
| struct device_domain_info *info = dev_iommu_priv_get(dev); | ||
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| cache_tag_unassign(domain, did, dev, pasid, CACHE_TAG_NESTING_IOTLB); | ||
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| if (info->ats_enabled) | ||
| cache_tag_unassign(domain, did, dev, pasid, CACHE_TAG_NESTING_DEVTLB); | ||
| } | ||
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| static u16 domain_get_id_for_dev(struct dmar_domain *domain, struct device *dev) | ||
| { | ||
| struct device_domain_info *info = dev_iommu_priv_get(dev); | ||
| struct intel_iommu *iommu = info->iommu; | ||
|
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| /* | ||
| * The driver assigns different domain IDs for all domains except | ||
| * the SVA type. | ||
| */ | ||
| if (domain->domain.type == IOMMU_DOMAIN_SVA) | ||
| return FLPT_DEFAULT_DID; | ||
|
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| return domain_id_iommu(domain, iommu); | ||
| } | ||
|
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| /* | ||
| * Assign cache tags to a domain when it's associated with a device's | ||
| * PASID using a specific domain ID. | ||
| * | ||
| * On success (return value of 0), cache tags are created and added to the | ||
| * domain's cache tag list. On failure (negative return value), an error | ||
| * code is returned indicating the reason for the failure. | ||
| */ | ||
| int cache_tag_assign_domain(struct dmar_domain *domain, | ||
| struct device *dev, ioasid_t pasid) | ||
| { | ||
| u16 did = domain_get_id_for_dev(domain, dev); | ||
| int ret; | ||
|
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| ret = __cache_tag_assign_domain(domain, did, dev, pasid); | ||
| if (ret || domain->domain.type != IOMMU_DOMAIN_NESTED) | ||
| return ret; | ||
|
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| ret = __cache_tag_assign_parent_domain(domain->s2_domain, did, dev, pasid); | ||
| if (ret) | ||
| __cache_tag_unassign_domain(domain, did, dev, pasid); | ||
|
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| return ret; | ||
| } | ||
|
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| /* | ||
| * Remove the cache tags associated with a device's PASID when the domain is | ||
| * detached from the device. | ||
| * | ||
| * The cache tags must be previously assigned to the domain by calling the | ||
| * assign interface. | ||
| */ | ||
| void cache_tag_unassign_domain(struct dmar_domain *domain, | ||
| struct device *dev, ioasid_t pasid) | ||
| { | ||
| u16 did = domain_get_id_for_dev(domain, dev); | ||
|
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| __cache_tag_unassign_domain(domain, did, dev, pasid); | ||
| if (domain->domain.type == IOMMU_DOMAIN_NESTED) | ||
| __cache_tag_unassign_parent_domain(domain->s2_domain, did, dev, pasid); | ||
| } |
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