From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9727DC433EF for ; Mon, 7 Feb 2022 07:00:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241383AbiBGG6b (ORCPT ); Mon, 7 Feb 2022 01:58:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42362 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357913AbiBGGo3 (ORCPT ); Mon, 7 Feb 2022 01:44:29 -0500 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 43B93C043185 for ; Sun, 6 Feb 2022 22:44:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1644216268; x=1675752268; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=lJxwiEIQSk9dgfIPGnEA9tRvOUzFf2hlDhpa/mB/TOA=; b=ZpiaXSxRty3tHBuOfqUcCEFhRp/R2FkC5ZWj3PNvI9Z8oOTqrOzVTX7y 4hz2Kz2nKm2Fxp6t2PcfVaCslLAe7Vl68bAspMCJWirl08hUCmkFwvhDU zSvyDAM/1YoTXRFXh/dv2IB8WHisb0xt/8cCwhceDxSPuUTmjVxteZ9ye hEGdtGcvS7ISc0OgjpYuNptpXqqeSL8pEG4CoWJflvOF0Y70A+sKlu47r TwDIyzVjfnBp5/3Fc0u0emGkOTNr9NGyNX4i2g7We13CNtrkNXwPWLU0i 9KvtyZe8ZXEmEFtZw0Fb/3YgR1gfLXn+x/A/ieyXDAPJNdnmpYi04UDH7 Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10250"; a="273171198" X-IronPort-AV: E=Sophos;i="5.88,349,1635231600"; d="scan'208";a="273171198" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Feb 2022 22:43:24 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,349,1635231600"; d="scan'208";a="525020319" Received: from allen-box.sh.intel.com ([10.239.159.118]) by orsmga007.jf.intel.com with ESMTP; 06 Feb 2022 22:43:21 -0800 From: Lu Baolu To: Joerg Roedel , Kevin Tian , Ashok Raj , Liu Yi L , Jacob Pan Cc: Robin Murphy , Jason Gunthorpe , Christoph Hellwig , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Lu Baolu Subject: [PATCH v1 08/10] iommu/vt-d: Use rculist for dmar_domain::devices Date: Mon, 7 Feb 2022 14:41:40 +0800 Message-Id: <20220207064142.1092846-9-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220207064142.1092846-1-baolu.lu@linux.intel.com> References: <20220207064142.1092846-1-baolu.lu@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use rculist for list of devices attached by a domain. And use the RCU lock for read/write protection. As both the global device_domain array and per-domain device_domain list are protected by RCU lock now, there is no need to use the spinlock anymore. Cleanup device_domain_lock. Signed-off-by: Lu Baolu --- include/linux/intel-iommu.h | 1 - drivers/iommu/intel/debugfs.c | 3 - drivers/iommu/intel/iommu.c | 118 ++++++++++++++-------------------- 3 files changed, 47 insertions(+), 75 deletions(-) diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index 1ccba739a062..2091576b5989 100644 --- a/include/linux/intel-iommu.h +++ b/include/linux/intel-iommu.h @@ -480,7 +480,6 @@ enum { #define VTD_FLAG_SVM_CAPABLE (1 << 2) extern int intel_iommu_sm; -extern spinlock_t device_domain_lock; #define sm_supported(iommu) (intel_iommu_sm && ecap_smts((iommu)->ecap)) #define pasid_supported(iommu) (sm_supported(iommu) && \ diff --git a/drivers/iommu/intel/debugfs.c b/drivers/iommu/intel/debugfs.c index db7a0ca73626..43137704f187 100644 --- a/drivers/iommu/intel/debugfs.c +++ b/drivers/iommu/intel/debugfs.c @@ -363,13 +363,10 @@ static int show_device_domain_translation(struct device *dev, void *data) static int domain_translation_struct_show(struct seq_file *m, void *unused) { - unsigned long flags; int ret; - spin_lock_irqsave(&device_domain_lock, flags); ret = bus_for_each_dev(&pci_bus_type, NULL, m, show_device_domain_translation); - spin_unlock_irqrestore(&device_domain_lock, flags); return ret; } diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index d7eba86c7f72..7d2fec3041e4 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -282,7 +282,6 @@ static int hw_pass_through = 1; static int g_num_of_iommus; static void domain_exit(struct dmar_domain *domain); -static void domain_remove_dev_info(struct dmar_domain *domain); static void dmar_remove_one_dev_info(struct device *dev); static void __dmar_remove_one_dev_info(struct device_domain_info *info); static int intel_iommu_attach_device(struct iommu_domain *domain, @@ -312,7 +311,6 @@ struct device_domain_info *get_domain_info(struct device *dev) return dev_iommu_priv_get(dev); } -DEFINE_SPINLOCK(device_domain_lock); static DEFINE_XARRAY_ALLOC(device_domain_array); #define DEVI_IDX(seg, bus, devfn) ((((u16)(seg)) << 16) | PCI_DEVID(bus, devfn)) @@ -590,12 +588,11 @@ static int domain_update_device_node(struct dmar_domain *domain) struct device_domain_info *info; int nid = NUMA_NO_NODE; - assert_spin_locked(&device_domain_lock); - if (list_empty(&domain->devices)) return NUMA_NO_NODE; - list_for_each_entry(info, &domain->devices, link) { + rcu_read_lock(); + list_for_each_entry_rcu(info, &domain->devices, link) { if (!info->dev) continue; @@ -609,6 +606,7 @@ static int domain_update_device_node(struct dmar_domain *domain) if (nid != NUMA_NO_NODE) break; } + rcu_read_unlock(); return nid; } @@ -1437,25 +1435,26 @@ static void __iommu_flush_iotlb(struct intel_iommu *iommu, u16 did, } static struct device_domain_info * -iommu_support_dev_iotlb (struct dmar_domain *domain, struct intel_iommu *iommu, - u8 bus, u8 devfn) +iommu_support_dev_iotlb(struct dmar_domain *domain, struct intel_iommu *iommu, + u8 bus, u8 devfn) { - struct device_domain_info *info; - - assert_spin_locked(&device_domain_lock); + struct device_domain_info *tmp, *info = NULL; if (!iommu->qi) return NULL; - list_for_each_entry(info, &domain->devices, link) - if (info->iommu == iommu && info->bus == bus && - info->devfn == devfn) { - if (info->ats_supported && info->dev) - return info; + rcu_read_lock(); + list_for_each_entry_rcu(tmp, &domain->devices, link) { + if (tmp->iommu == iommu && tmp->bus == bus && + tmp->devfn == devfn) { + if (tmp->ats_supported && tmp->dev) + info = tmp; break; } + } + rcu_read_unlock(); - return NULL; + return info; } static void domain_update_iotlb(struct dmar_domain *domain) @@ -1463,13 +1462,14 @@ static void domain_update_iotlb(struct dmar_domain *domain) struct device_domain_info *info; bool has_iotlb_device = false; - assert_spin_locked(&device_domain_lock); - - list_for_each_entry(info, &domain->devices, link) + rcu_read_lock(); + list_for_each_entry_rcu(info, &domain->devices, link) { if (info->ats_enabled) { has_iotlb_device = true; break; } + } + rcu_read_unlock(); domain->has_iotlb_device = has_iotlb_device; } @@ -1478,8 +1478,6 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info) { struct pci_dev *pdev; - assert_spin_locked(&device_domain_lock); - if (!info || !dev_is_pci(info->dev)) return; @@ -1525,8 +1523,6 @@ static void iommu_disable_dev_iotlb(struct device_domain_info *info) { struct pci_dev *pdev; - assert_spin_locked(&device_domain_lock); - if (!dev_is_pci(info->dev)) return; @@ -1566,17 +1562,15 @@ static void __iommu_flush_dev_iotlb(struct device_domain_info *info, static void iommu_flush_dev_iotlb(struct dmar_domain *domain, u64 addr, unsigned mask) { - unsigned long flags; struct device_domain_info *info; if (!domain->has_iotlb_device) return; - spin_lock_irqsave(&device_domain_lock, flags); - list_for_each_entry(info, &domain->devices, link) + rcu_read_lock(); + list_for_each_entry_rcu(info, &domain->devices, link) __iommu_flush_dev_iotlb(info, addr, mask); - - spin_unlock_irqrestore(&device_domain_lock, flags); + rcu_read_unlock(); } static void iommu_flush_iotlb_psi(struct intel_iommu *iommu, @@ -1821,7 +1815,7 @@ static struct dmar_domain *alloc_domain(unsigned int type) if (first_level_by_default(type)) domain->flags |= DOMAIN_FLAG_USE_FIRST_LEVEL; domain->has_iotlb_device = false; - INIT_LIST_HEAD(&domain->devices); + INIT_LIST_HEAD_RCU(&domain->devices); return domain; } @@ -1833,7 +1827,6 @@ static int domain_attach_iommu(struct dmar_domain *domain, unsigned long ndomains; int num; - assert_spin_locked(&device_domain_lock); assert_spin_locked(&iommu->lock); domain->iommu_refcnt[iommu->seq_id] += 1; @@ -1861,7 +1854,6 @@ static void domain_detach_iommu(struct dmar_domain *domain, { int num; - assert_spin_locked(&device_domain_lock); assert_spin_locked(&iommu->lock); domain->iommu_refcnt[iommu->seq_id] -= 1; @@ -1890,8 +1882,15 @@ static inline int guestwidth_to_adjustwidth(int gaw) static void domain_exit(struct dmar_domain *domain) { - /* Remove associated devices and clear attached or cached domains */ - domain_remove_dev_info(domain); + struct device_domain_info *info, *tmp; + + /* + * Remove associated devices and clear attached or cached domains. + * No worries about new devices insertion or removal. Hence no need + * for a lock here. + */ + list_for_each_entry_safe(info, tmp, &domain->devices, link) + __dmar_remove_one_dev_info(info); if (domain->pgd) { LIST_HEAD(freelist); @@ -1974,9 +1973,7 @@ static int domain_context_mapping_one(struct dmar_domain *domain, BUG_ON(!domain->pgd); - spin_lock_irqsave(&device_domain_lock, flags); - spin_lock(&iommu->lock); - + spin_lock_irqsave(&iommu->lock, flags); ret = -ENOMEM; context = iommu_context_addr(iommu, bus, devfn, 1); if (!context) @@ -2095,8 +2092,7 @@ static int domain_context_mapping_one(struct dmar_domain *domain, ret = 0; out_unlock: - spin_unlock(&iommu->lock); - spin_unlock_irqrestore(&device_domain_lock, flags); + spin_unlock_irqrestore(&iommu->lock, flags); return ret; } @@ -2385,25 +2381,13 @@ static void domain_context_clear_one(struct device_domain_info *info, u8 bus, u8 static inline void unlink_domain_info(struct device_domain_info *info) { - assert_spin_locked(&device_domain_lock); - list_del(&info->link); + list_del_rcu(&info->link); xa_erase(&device_domain_array, DEVI_IDX(info->segment, info->bus, info->devfn)); if (info->dev) dev_iommu_priv_set(info->dev, NULL); } -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(info); - spin_unlock_irqrestore(&device_domain_lock, flags); -} - struct dmar_domain *find_domain(struct device *dev) { struct device_domain_info *info; @@ -2470,17 +2454,14 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, unsigned long flags; int ret; - spin_lock_irqsave(&device_domain_lock, flags); - info->domain = domain; - spin_lock(&iommu->lock); + spin_lock_irqsave(&iommu->lock, flags); ret = domain_attach_iommu(domain, iommu); - spin_unlock(&iommu->lock); - if (ret) { - spin_unlock_irqrestore(&device_domain_lock, flags); + spin_unlock_irqrestore(&iommu->lock, flags); + if (ret) return NULL; - } - list_add(&info->link, &domain->devices); - spin_unlock_irqrestore(&device_domain_lock, flags); + + info->domain = domain; + list_add_rcu(&info->link, &domain->devices); /* PASID table is mandatory for a PCI device in scalable mode. */ if (dev && dev_is_pci(dev) && sm_supported(iommu)) { @@ -4004,8 +3985,6 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info) struct intel_iommu *iommu; unsigned long flags; - assert_spin_locked(&device_domain_lock); - if (WARN_ON(!info)) return; @@ -4013,9 +3992,12 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info) domain = info->domain; if (info->dev && !dev_is_real_dma_subdevice(info->dev)) { - if (dev_is_pci(info->dev) && sm_supported(iommu)) + if (dev_is_pci(info->dev) && sm_supported(iommu)) { + spin_lock_irqsave(&iommu->lock, flags); intel_pasid_tear_down_entry(iommu, info->dev, PASID_RID2PASID, false); + spin_unlock_irqrestore(&iommu->lock, flags); + } iommu_disable_dev_iotlb(info); domain_context_clear(info); @@ -4034,13 +4016,10 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info) static void dmar_remove_one_dev_info(struct device *dev) { struct device_domain_info *info; - unsigned long flags; - spin_lock_irqsave(&device_domain_lock, flags); info = get_domain_info(dev); if (info) __dmar_remove_one_dev_info(info); - spin_unlock_irqrestore(&device_domain_lock, flags); } static int md_domain_init(struct dmar_domain *domain, int guest_width) @@ -4476,9 +4455,7 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev) if (!domain) return -EINVAL; - spin_lock_irqsave(&device_domain_lock, flags); - spin_lock(&iommu->lock); - + spin_lock_irqsave(&iommu->lock, flags); ret = -EINVAL; info = get_domain_info(dev); if (!info || !info->pasid_supported) @@ -4508,8 +4485,7 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev) ret = 0; out: - spin_unlock(&iommu->lock); - spin_unlock_irqrestore(&device_domain_lock, flags); + spin_unlock_irqrestore(&iommu->lock, flags); return ret; } -- 2.25.1