From d160aca5276d093fc68d6ff48888586c90309d03 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Wed, 22 Jul 2015 11:52:53 +0200 Subject: [PATCH] iommu/vt-d: Unify domain->iommu attach/detachment Move the code to attach/detach domains to iommus and vice verce into a single function to make sure there are no dangling references. Signed-off-by: Joerg Roedel --- drivers/iommu/intel-iommu.c | 125 ++++++++++++++---------------------- 1 file changed, 49 insertions(+), 76 deletions(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 46359bd9da63..1cb7a3eb29d3 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -1678,90 +1678,64 @@ static struct dmar_domain *alloc_domain(int flags) return domain; } -static int __iommu_attach_domain(struct dmar_domain *domain, - struct intel_iommu *iommu) +/* Must be called with iommu->lock */ +static int domain_attach_iommu(struct dmar_domain *domain, + struct intel_iommu *iommu) { - int num; unsigned long ndomains; - - num = domain->iommu_did[iommu->seq_id]; - if (num) - return num; - - ndomains = cap_ndoms(iommu->cap); - num = find_first_zero_bit(iommu->domain_ids, ndomains); - - if (num < ndomains) { - set_bit(num, iommu->domain_ids); - set_iommu_domain(iommu, num, domain); - domain->iommu_did[iommu->seq_id] = num; - } else { - num = -ENOSPC; - } - - if (num < 0) - pr_err("%s: No free domain ids\n", iommu->name); - - return num; -} - -static int iommu_attach_domain(struct dmar_domain *domain, - struct intel_iommu *iommu) -{ - int num; unsigned long flags; + int ret, num; - spin_lock_irqsave(&iommu->lock, flags); - num = __iommu_attach_domain(domain, iommu); - spin_unlock_irqrestore(&iommu->lock, flags); - - return num; -} - -static void iommu_detach_domain(struct dmar_domain *domain, - struct intel_iommu *iommu) -{ - unsigned long flags; - int num; - - spin_lock_irqsave(&iommu->lock, flags); - - num = domain->iommu_did[iommu->seq_id]; - - if (num == 0) - return; - - clear_bit(num, iommu->domain_ids); - set_iommu_domain(iommu, num, NULL); - - spin_unlock_irqrestore(&iommu->lock, flags); -} - -static void domain_attach_iommu(struct dmar_domain *domain, - struct intel_iommu *iommu) -{ - unsigned long flags; + assert_spin_locked(&iommu->lock); spin_lock_irqsave(&domain->iommu_lock, flags); + domain->iommu_refcnt[iommu->seq_id] += 1; domain->iommu_count += 1; if (domain->iommu_refcnt[iommu->seq_id] == 1) { - domain->nid = iommu->node; + ndomains = cap_ndoms(iommu->cap); + num = find_first_zero_bit(iommu->domain_ids, ndomains); + + if (num >= ndomains) { + pr_err("%s: No free domain ids\n", iommu->name); + domain->iommu_refcnt[iommu->seq_id] -= 1; + domain->iommu_count -= 1; + ret = -ENOSPC; + goto out_unlock; + } + + set_bit(num, iommu->domain_ids); + set_iommu_domain(iommu, num, domain); + + domain->iommu_did[iommu->seq_id] = num; + domain->nid = iommu->node; + domain_update_iommu_cap(domain); } + + ret = 0; +out_unlock: spin_unlock_irqrestore(&domain->iommu_lock, flags); + + return ret; } static int domain_detach_iommu(struct dmar_domain *domain, struct intel_iommu *iommu) { + int num, count = INT_MAX; unsigned long flags; - int count = INT_MAX; + + assert_spin_locked(&iommu->lock); spin_lock_irqsave(&domain->iommu_lock, flags); domain->iommu_refcnt[iommu->seq_id] -= 1; count = --domain->iommu_count; if (domain->iommu_refcnt[iommu->seq_id] == 0) { + num = domain->iommu_did[iommu->seq_id]; + clear_bit(num, iommu->domain_ids); + set_iommu_domain(iommu, num, NULL); + domain_update_iommu_cap(domain); domain->iommu_did[iommu->seq_id] = 0; } @@ -1886,7 +1860,6 @@ static int domain_init(struct dmar_domain *domain, struct intel_iommu *iommu, static void domain_exit(struct dmar_domain *domain) { struct page *freelist = NULL; - int i; /* Domain 0 is reserved, so dont process it */ if (!domain) @@ -1896,20 +1869,16 @@ static void domain_exit(struct dmar_domain *domain) if (!intel_iommu_strict) flush_unmaps_timeout(0); - /* remove associated devices */ + /* Remove associated devices and clear attached or cached domains */ + rcu_read_lock(); domain_remove_dev_info(domain); + rcu_read_unlock(); /* destroy iovas */ put_iova_domain(&domain->iovad); freelist = domain_unmap(domain, 0, DOMAIN_MAX_PFN(domain->gaw)); - /* clear attached or cached domains */ - rcu_read_lock(); - for_each_domain_iommu(i, domain) - iommu_detach_domain(domain, g_iommus[i]); - rcu_read_unlock(); - dma_free_pagelist(freelist); free_domain_mem(domain); @@ -2286,6 +2255,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, struct dmar_domain *found = NULL; struct device_domain_info *info; unsigned long flags; + int ret; info = alloc_devinfo_mem(); if (!info) @@ -2313,11 +2283,14 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, return found; } - if (iommu_attach_domain(domain, iommu) < 0) { + spin_lock(&iommu->lock); + ret = domain_attach_iommu(domain, iommu); + spin_unlock(&iommu->lock); + + if (ret) { spin_unlock_irqrestore(&device_domain_lock, flags); return NULL; } - domain_attach_iommu(domain, iommu); list_add(&info->link, &domain->devices); list_add(&info->global, &device_domain_list); @@ -4590,12 +4563,10 @@ static void dmar_remove_one_dev_info(struct dmar_domain *domain, iommu_disable_dev_iotlb(info); domain_context_clear(iommu, dev); free_devinfo_mem(info); - domain_detach_iommu(domain, iommu); - spin_lock_irqsave(&domain->iommu_lock, flags); - if (!domain->iommu_refcnt[iommu->seq_id]) - iommu_detach_domain(domain, iommu); - spin_unlock_irqrestore(&domain->iommu_lock, flags); + spin_lock_irqsave(&iommu->lock, flags); + domain_detach_iommu(domain, iommu); + spin_unlock_irqrestore(&iommu->lock, flags); } static int md_domain_init(struct dmar_domain *domain, int guest_width) @@ -4676,10 +4647,12 @@ static int intel_iommu_attach_device(struct iommu_domain *domain, old_domain = find_domain(dev); if (old_domain) { + rcu_read_lock(); if (domain_type_is_vm_or_si(dmar_domain)) dmar_remove_one_dev_info(old_domain, dev); else domain_remove_dev_info(old_domain); + rcu_read_unlock(); if (!domain_type_is_vm_or_si(old_domain) && list_empty(&old_domain->devices))