From nobody Sun Feb 8 21:46:18 2026 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 99203DDCF for ; Thu, 15 Feb 2024 07:28:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.15 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707982133; cv=none; b=JO3tHxZawsyAbGjp67uuHVCHCB32YvSoHNbYM2ZuAirWxcyuSJnWLuAogeMLv6Rf5rGcwUCxuMHrpbano/GfuuvTcpEtto03L9isT9Y0Ou96+pE3JUratmGVv2SbsIIA7KNrrWSqQDfTmjyqGugHz9jeOPg5EVJHnlCZQu+OYhk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707982133; c=relaxed/simple; bh=TMjeJSIkcMJLmOlEVy9pSoQQPSex5IwLFXnsMQdCurc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=aR/XjWQu1TEKyRByzp7lHGEKVQZcoY1sJOWuuFNko5wzK7mJw1xBJF69BgeFNwaBIDJXfXgP33ak7gEi+B+Pn1GFVjYPMt1sIRnZ+Ewo8ygVXN0tTZLyTxgQl3X0GolKeEiwjVvuYaAgQEKUuYpCtGp1TxytVbobNBk05qVaqME= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=DI97xG42; arc=none smtp.client-ip=192.198.163.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="DI97xG42" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1707982132; x=1739518132; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=TMjeJSIkcMJLmOlEVy9pSoQQPSex5IwLFXnsMQdCurc=; b=DI97xG42qnrIccXxgVqKj78Iyo08Q+aGvZPQeabwDi9W/Dy062Gi6g89 JNUL53ER+q7kKsHtpkA25HZe8vGyqWo97e3C/HELTthN0wAKGc111V8tI iJltre19qa2oCyk6vmPN+/XulN6Szoy8iHeZcBO3X+YYMRUD0SXhknffh sAT3irQucjlg+Z5WbyJVy1pdGYvQAPzGu/cjZikZrC9GY6IzXU90FQY0l gbM1rXjjwks/L13f0LioFNV6NL+F9sYLyYvdh8O8wiHmJjU7yOPdYjFDp pOEydGAD/Ho3lQcGfwNdIUQvrGBu0d+5QXVHevPZ/AAxvoiK+M6kjteQ6 A==; X-IronPort-AV: E=McAfee;i="6600,9927,10984"; a="2182713" X-IronPort-AV: E=Sophos;i="6.06,161,1705392000"; d="scan'208";a="2182713" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Feb 2024 23:28:51 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10984"; a="912113139" X-IronPort-AV: E=Sophos;i="6.06,161,1705392000"; d="scan'208";a="912113139" Received: from allen-box.sh.intel.com ([10.239.159.127]) by fmsmga002.fm.intel.com with ESMTP; 14 Feb 2024 23:28:48 -0800 From: Lu Baolu To: Joerg Roedel , Will Deacon , Robin Murphy , Jason Gunthorpe , Kevin Tian Cc: Huang Jiaqing , Ethan Zhao , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, Lu Baolu Subject: [PATCH 1/2] iommu/vt-d: Use rbtree to track iommu probed devices Date: Thu, 15 Feb 2024 15:22:48 +0800 Message-Id: <20240215072249.4465-2-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240215072249.4465-1-baolu.lu@linux.intel.com> References: <20240215072249.4465-1-baolu.lu@linux.intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Use a red-black tree(rbtree) to track devices probed by the driver's probe_device callback. These devices need to be looked up quickly by a source ID when the hardware reports a fault, either recoverable or unrecoverable. Fault reporting paths are critical. Searching a list in this scenario is inefficient, with an algorithm complexity of O(n). An rbtree is a self-balancing binary search tree, offering an average search time complexity of O(log(n)). This significant performance improvement makes rbtrees a better choice. Furthermore, rbtrees are implemented on a per-iommu basis, eliminating the need for global searches and further enhancing efficiency in critical fault paths. The rbtree is protected by a spin lock with interrupts disabled to ensure thread-safe access even within interrupt contexts. Co-developed-by: Huang Jiaqing Signed-off-by: Huang Jiaqing Signed-off-by: Lu Baolu Reviewed-by: Jason Gunthorpe --- drivers/iommu/intel/iommu.h | 7 +++++ drivers/iommu/intel/dmar.c | 3 +- drivers/iommu/intel/iommu.c | 62 +++++++++++++++++++++++++++++++++++-- 3 files changed, 69 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h index cf9a28c7fab8..54eeaa8e35a9 100644 --- a/drivers/iommu/intel/iommu.h +++ b/drivers/iommu/intel/iommu.h @@ -716,6 +716,11 @@ struct intel_iommu { struct q_inval *qi; /* Queued invalidation info */ u32 iommu_state[MAX_SR_DMAR_REGS]; /* Store iommu states between suspend = and resume.*/ =20 + /* rb tree for all probed devices */ + struct rb_root device_rbtree; + /* protect the device_rbtree */ + spinlock_t device_rbtree_lock; + #ifdef CONFIG_IRQ_REMAP struct ir_table *ir_table; /* Interrupt remapping info */ struct irq_domain *ir_domain; @@ -749,6 +754,8 @@ struct device_domain_info { struct intel_iommu *iommu; /* IOMMU used by this device */ struct dmar_domain *domain; /* pointer to domain */ struct pasid_table *pasid_table; /* pasid table */ + /* device tracking node(lookup by PCI RID) */ + struct rb_node node; #ifdef CONFIG_INTEL_IOMMU_DEBUGFS struct dentry *debugfs_dentry; /* pointer to device directory dentry */ #endif diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c index 23cb80d62a9a..f9b63c2875f7 100644 --- a/drivers/iommu/intel/dmar.c +++ b/drivers/iommu/intel/dmar.c @@ -1095,7 +1095,8 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd) iommu->agaw =3D agaw; iommu->msagaw =3D msagaw; iommu->segment =3D drhd->segment; - + iommu->device_rbtree =3D RB_ROOT; + spin_lock_init(&iommu->device_rbtree_lock); iommu->node =3D NUMA_NO_NODE; =20 ver =3D readl(iommu->reg + DMAR_VER_REG); diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index a81a2be9b870..09009d96e553 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -96,6 +96,55 @@ static phys_addr_t root_entry_uctp(struct root_entry *re) return re->hi & VTD_PAGE_MASK; } =20 +static int device_rid_cmp_key(const void *key, const struct rb_node *node) +{ + struct device_domain_info *info =3D + rb_entry(node, struct device_domain_info, node); + const u16 *rid_lhs =3D key; + + if (*rid_lhs < PCI_DEVID(info->bus, info->devfn)) + return -1; + + if (*rid_lhs > PCI_DEVID(info->bus, info->devfn)) + return 1; + + return 0; +} + +static int device_rid_cmp(struct rb_node *lhs, const struct rb_node *rhs) +{ + struct device_domain_info *info =3D + rb_entry(lhs, struct device_domain_info, node); + u16 key =3D PCI_DEVID(info->bus, info->devfn); + + return device_rid_cmp_key(&key, rhs); +} + +static int device_rbtree_insert(struct intel_iommu *iommu, + struct device_domain_info *info) +{ + struct rb_node *curr; + unsigned long flags; + + spin_lock_irqsave(&iommu->device_rbtree_lock, flags); + curr =3D rb_find_add(&info->node, &iommu->device_rbtree, device_rid_cmp); + spin_unlock_irqrestore(&iommu->device_rbtree_lock, flags); + if (curr) + dev_warn(info->dev, "device already in rbtree\n"); + + return curr ? -EEXIST : 0; +} + +static void device_rbtree_remove(struct device_domain_info *info) +{ + struct intel_iommu *iommu =3D info->iommu; + unsigned long flags; + + spin_lock_irqsave(&iommu->device_rbtree_lock, flags); + rb_erase(&info->node, &iommu->device_rbtree); + spin_unlock_irqrestore(&iommu->device_rbtree_lock, flags); +} + /* * This domain is a statically identity mapping domain. * 1. This domain creats a static 1:1 mapping to all usable memory. @@ -4264,25 +4313,34 @@ static struct iommu_device *intel_iommu_probe_devic= e(struct device *dev) } =20 dev_iommu_priv_set(dev, info); + ret =3D device_rbtree_insert(iommu, info); + if (ret) + goto free; =20 if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev)) { ret =3D intel_pasid_alloc_table(dev); if (ret) { dev_err(dev, "PASID table allocation failed\n"); - kfree(info); - return ERR_PTR(ret); + goto clear_rbtree; } } =20 intel_iommu_debugfs_create_dev(info); =20 return &iommu->iommu; +clear_rbtree: + device_rbtree_remove(info); +free: + kfree(info); + + return ERR_PTR(ret); } =20 static void intel_iommu_release_device(struct device *dev) { struct device_domain_info *info =3D dev_iommu_priv_get(dev); =20 + device_rbtree_remove(info); dmar_remove_one_dev_info(dev); intel_pasid_free_table(dev); intel_iommu_debugfs_remove_dev(info); --=20 2.34.1