From: Joerg Roedel Date: Wed, 22 Jul 2015 14:50:40 +0000 (+0200) Subject: iommu/vt-d: Get rid of domain->iommu_lock X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=55d940430ab91b89ff5fc7240555544d86475783;p=linux-beck.git iommu/vt-d: Get rid of domain->iommu_lock When this lock is held the device_domain_lock is also required to make sure the device_domain_info does not vanish while in use. So this lock can be removed as it gives no additional protection. Signed-off-by: Joerg Roedel --- diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index c8d9bef776da..0f258f0f5ac0 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -406,7 +406,6 @@ struct dmar_domain { int iommu_superpage;/* Level of superpages supported: 0 == 4KiB (no superpages), 1 == 2MiB, 2 == 1GiB, 3 == 512GiB, 4 == 1TiB */ - spinlock_t iommu_lock; /* protect iommu set in domain */ u64 max_addr; /* maximum mapped address */ struct iommu_domain domain; /* generic domain data structure for @@ -476,6 +475,8 @@ static void dmar_remove_one_dev_info(struct dmar_domain *domain, struct device *dev); static void domain_context_clear(struct intel_iommu *iommu, struct device *dev); +static void __dmar_remove_one_dev_info(struct dmar_domain *domain, + struct device *dev); static int domain_detach_iommu(struct dmar_domain *domain, struct intel_iommu *iommu); @@ -1404,24 +1405,23 @@ iommu_support_dev_iotlb (struct dmar_domain *domain, struct intel_iommu *iommu, u8 bus, u8 devfn) { bool found = false; - unsigned long flags; struct device_domain_info *info; struct pci_dev *pdev; + assert_spin_locked(&device_domain_lock); + if (!ecap_dev_iotlb_support(iommu->ecap)) return NULL; if (!iommu->qi) return NULL; - spin_lock_irqsave(&device_domain_lock, flags); list_for_each_entry(info, &domain->devices, link) if (info->iommu == iommu && info->bus == bus && info->devfn == devfn) { found = true; break; } - spin_unlock_irqrestore(&device_domain_lock, flags); if (!found || !info->dev || !dev_is_pci(info->dev)) return NULL; @@ -1616,10 +1616,12 @@ static int iommu_init_domains(struct intel_iommu *iommu) static void disable_dmar_iommu(struct intel_iommu *iommu) { struct device_domain_info *info, *tmp; + unsigned long flags; if (!iommu->domains || !iommu->domain_ids) return; + spin_lock_irqsave(&device_domain_lock, flags); list_for_each_entry_safe(info, tmp, &device_domain_list, global) { struct dmar_domain *domain; @@ -1636,6 +1638,7 @@ static void disable_dmar_iommu(struct intel_iommu *iommu) if (!domain_type_is_vm_or_si(domain)) domain_exit(domain); } + spin_unlock_irqrestore(&device_domain_lock, flags); if (iommu->gcmd & DMA_GCMD_TE) iommu_disable_translation(iommu); @@ -1672,7 +1675,6 @@ static struct dmar_domain *alloc_domain(int flags) memset(domain, 0, sizeof(*domain)); domain->nid = -1; domain->flags = flags; - spin_lock_init(&domain->iommu_lock); INIT_LIST_HEAD(&domain->devices); return domain; @@ -1683,13 +1685,11 @@ static int domain_attach_iommu(struct dmar_domain *domain, struct intel_iommu *iommu) { unsigned long ndomains; - unsigned long flags; - int ret, num; + int num; + assert_spin_locked(&device_domain_lock); 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) { @@ -1700,8 +1700,7 @@ static int domain_attach_iommu(struct dmar_domain *domain, 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; + return -ENOSPC; } set_bit(num, iommu->domain_ids); @@ -1713,22 +1712,17 @@ static int domain_attach_iommu(struct dmar_domain *domain, domain_update_iommu_cap(domain); } - ret = 0; -out_unlock: - spin_unlock_irqrestore(&domain->iommu_lock, flags); - - return ret; + return 0; } static int domain_detach_iommu(struct dmar_domain *domain, struct intel_iommu *iommu) { int num, count = INT_MAX; - unsigned long flags; + assert_spin_locked(&device_domain_lock); 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) { @@ -1739,7 +1733,6 @@ static int domain_detach_iommu(struct dmar_domain *domain, domain_update_iommu_cap(domain); domain->iommu_did[iommu->seq_id] = 0; } - spin_unlock_irqrestore(&domain->iommu_lock, flags); return count; } @@ -1894,7 +1887,7 @@ static int domain_context_mapping_one(struct dmar_domain *domain, struct context_entry *context; unsigned long flags; struct dma_pte *pgd; - int agaw; + int ret, agaw; WARN_ON(did == 0); @@ -1906,16 +1899,17 @@ static int domain_context_mapping_one(struct dmar_domain *domain, BUG_ON(!domain->pgd); - spin_lock_irqsave(&iommu->lock, flags); + spin_lock_irqsave(&device_domain_lock, flags); + spin_lock(&iommu->lock); + + ret = -ENOMEM; context = iommu_context_addr(iommu, bus, devfn, 1); - spin_unlock_irqrestore(&iommu->lock, flags); if (!context) - return -ENOMEM; - spin_lock_irqsave(&iommu->lock, flags); - if (context_present(context)) { - spin_unlock_irqrestore(&iommu->lock, flags); - return 0; - } + goto out_unlock; + + ret = 0; + if (context_present(context)) + goto out_unlock; pgd = domain->pgd; @@ -1928,11 +1922,10 @@ static int domain_context_mapping_one(struct dmar_domain *domain, */ if (translation != CONTEXT_TT_PASS_THROUGH) { for (agaw = domain->agaw; agaw != iommu->agaw; agaw--) { + ret = -ENOMEM; pgd = phys_to_virt(dma_pte_addr(pgd)); - if (!dma_pte_present(pgd)) { - spin_unlock_irqrestore(&iommu->lock, flags); - return -ENOMEM; - } + if (!dma_pte_present(pgd)) + goto out_unlock; } info = iommu_support_dev_iotlb(domain, iommu, bus, devfn); @@ -1971,7 +1964,12 @@ static int domain_context_mapping_one(struct dmar_domain *domain, iommu_flush_write_buffer(iommu); } iommu_enable_dev_iotlb(info); - spin_unlock_irqrestore(&iommu->lock, flags); + + ret = 0; + +out_unlock: + spin_unlock(&iommu->lock); + spin_unlock_irqrestore(&device_domain_lock, flags); return 0; } @@ -2214,9 +2212,12 @@ static inline void unlink_domain_info(struct device_domain_info *info) static void domain_remove_dev_info(struct dmar_domain *domain) { struct device_domain_info *info, *tmp; + unsigned long flags; + spin_lock_irqsave(&device_domain_lock, flags); list_for_each_entry_safe(info, tmp, &domain->devices, link) - dmar_remove_one_dev_info(domain, info->dev); + __dmar_remove_one_dev_info(domain, info->dev); + spin_unlock_irqrestore(&device_domain_lock, flags); } /* @@ -4539,14 +4540,16 @@ static void domain_context_clear(struct intel_iommu *iommu, struct device *dev) pci_for_each_dma_alias(to_pci_dev(dev), &domain_context_clear_one_cb, iommu); } -static void dmar_remove_one_dev_info(struct dmar_domain *domain, - struct device *dev) +static void __dmar_remove_one_dev_info(struct dmar_domain *domain, + struct device *dev) { struct device_domain_info *info; struct intel_iommu *iommu; unsigned long flags; u8 bus, devfn; + assert_spin_locked(&device_domain_lock); + iommu = device_to_iommu(dev, &bus, &devfn); if (!iommu) return; @@ -4556,9 +4559,7 @@ static void dmar_remove_one_dev_info(struct dmar_domain *domain, if (WARN_ON(!info)) return; - spin_lock_irqsave(&device_domain_lock, flags); unlink_domain_info(info); - spin_unlock_irqrestore(&device_domain_lock, flags); iommu_disable_dev_iotlb(info); domain_context_clear(iommu, dev); @@ -4569,6 +4570,16 @@ static void dmar_remove_one_dev_info(struct dmar_domain *domain, spin_unlock_irqrestore(&iommu->lock, flags); } +static void dmar_remove_one_dev_info(struct dmar_domain *domain, + struct device *dev) +{ + unsigned long flags; + + spin_lock_irqsave(&device_domain_lock, flags); + __dmar_remove_one_dev_info(domain, dev); + spin_unlock_irqrestore(&device_domain_lock, flags); +} + static int md_domain_init(struct dmar_domain *domain, int guest_width) { int adjust_width;