From patchwork Tue Jul 21 00:14:05 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bjorn Helgaas X-Patchwork-Id: 6831421 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: patchwork-linux-pci@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id CA4CBC05AC for ; Tue, 21 Jul 2015 00:14:14 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5680C2069F for ; Tue, 21 Jul 2015 00:14:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 220012064E for ; Tue, 21 Jul 2015 00:14:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757395AbbGUAOK (ORCPT ); Mon, 20 Jul 2015 20:14:10 -0400 Received: from mail-ig0-f175.google.com ([209.85.213.175]:36658 "EHLO mail-ig0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757247AbbGUAOJ (ORCPT ); Mon, 20 Jul 2015 20:14:09 -0400 Received: by igbij6 with SMTP id ij6so95434451igb.1 for ; Mon, 20 Jul 2015 17:14:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=subject:to:from:cc:date:message-id:in-reply-to:references :user-agent:mime-version:content-type:content-transfer-encoding; bh=KRhHjnHO44LRX0zGzd1bW2ENd4qeNTvSxy6LljUZIxg=; b=NUaP5zyTx3q1TNkjREdbq+fTdizx0ECxS2msQ38fRwDVsH35Bh2eZzKftz8yWmz8I1 h84MYpYlSMQYsg5xCjVxSvuYsb28Z0zStVQsdoN+nyNZXWRvd2UG8tCWN+aThXLBC9CH KRZjirPDH/cH2YekswpCh+mVhbbfEe8Xcxwoj8EhCSZOGEvr2wFb7Obe6IqW4pAn38Ih 4KigywI4mlE/s7+YIVS2bF0U4jZOE3loOaEe6g0nHI6gqCeXlHdsqzXaenCNTvWr2aYq UWcQqKzYQiZfZNLGZhJSRPNeoJ077bFh2T5yFwjBw4FZOfayUgKPH5a6K4xZOsK9ApuH m//w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:from:cc:date:message-id:in-reply-to :references:user-agent:mime-version:content-type :content-transfer-encoding; bh=KRhHjnHO44LRX0zGzd1bW2ENd4qeNTvSxy6LljUZIxg=; b=TRbNJeb+FU3uSR8fq9RIBY33e6VbZa4j7pkHuZaBTIWBxUw79ZmEIRl85QKelCgTST VP09BuiDrNArHtW7KvGVinUAW+tVST8b8yxuRXdeU8SJHbBl11etBEqCJ8v7pMvV3eK6 vd/TV6dq/m0VZYVwHPgWtrSPHlkzCz8cCHarcvCczDbTXg17YDc/bHQqfPHC0TT2htAt ov+/7D/Muk2drzUhjiscTB6QB7A5qr3WpPJfDtco/Y8Ui2KaoyEckKZSv+8ezgrpcjYZ aoC1Q0B6lIiWux9SXC30yOlpCYP17RVZU51LMNnlsmaucNedBOGfjJhWZwhH4uFPs5aP U7jg== X-Gm-Message-State: ALoCoQlaEeSfrckaO9v/o4CZuXBoKGxbTEg3U7V5/T+m2zZEvzGR8WeZ4sP1pHMLJaWc2e3+WxPY X-Received: by 10.107.131.70 with SMTP id f67mr39411023iod.47.1437437648738; Mon, 20 Jul 2015 17:14:08 -0700 (PDT) Received: from localhost ([69.71.1.1]) by smtp.gmail.com with ESMTPSA id i13sm3915031ioe.4.2015.07.20.17.14.06 (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Mon, 20 Jul 2015 17:14:07 -0700 (PDT) Subject: [PATCH v2 02/11] PCI: Allocate ATS struct during enumeration To: linux-pci@vger.kernel.org, Joerg Roedel , David Woodhouse From: Bjorn Helgaas Cc: iommu@lists.linux-foundation.org, Gregor Dick Date: Mon, 20 Jul 2015 19:14:05 -0500 Message-ID: <20150721001405.28145.43004.stgit@bhelgaas-glaptop2.roam.corp.google.com> In-Reply-To: <20150721001243.28145.81610.stgit@bhelgaas-glaptop2.roam.corp.google.com> References: <20150721001243.28145.81610.stgit@bhelgaas-glaptop2.roam.corp.google.com> User-Agent: StGit/0.16 MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Spam-Status: No, score=-8.0 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Previously, we allocated pci_ats structures when an IOMMU driver called pci_enable_ats(). An SR-IOV VF shares the STU setting with its PF, so when enabling ATS on the VF, we allocated a pci_ats struct for the PF if it didn't already have one. We held the sriov->lock to serialize threads concurrently enabling ATS on several VFS so only one would allocate the PF pci_ats. Gregor reported a deadlock here: pci_enable_sriov sriov_enable virtfn_add mutex_lock(dev->sriov->lock) # acquire sriov->lock pci_device_add device_add BUS_NOTIFY_ADD_DEVICE notifier chain iommu_bus_notifier amd_iommu_add_device # iommu_ops.add_device init_iommu_group iommu_group_get_for_dev iommu_group_add_device __iommu_attach_device amd_iommu_attach_device # iommu_ops.attach_device attach_device pci_enable_ats mutex_lock(dev->sriov->lock) # deadlock There's no reason to delay allocating the pci_ats struct, and if we allocate it for each device at enumeration-time, there's no need for locking in pci_enable_ats(). Allocate pci_ats struct during enumeration, when we initialize other capabilities. Note that this implementation requires ATS to be enabled on the PF first, before on any of the VFs because the PF controls the STU for all the VFs. Link: http://permalink.gmane.org/gmane.linux.kernel.iommu/9433 Reported-by: Gregor Dick Signed-off-by: Bjorn Helgaas Reviewed-by: Joerg Roedel --- drivers/pci/ats.c | 98 ++++++++++++++++++++--------------------------- drivers/pci/probe.c | 3 + drivers/pci/remove.c | 1 include/linux/pci-ats.h | 2 - include/linux/pci.h | 9 ++++ 5 files changed, 56 insertions(+), 57 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c index a8099d4..2026f53 100644 --- a/drivers/pci/ats.c +++ b/drivers/pci/ats.c @@ -17,7 +17,7 @@ #include "pci.h" -static int ats_alloc_one(struct pci_dev *dev, int ps) +static void ats_alloc_one(struct pci_dev *dev) { int pos; u16 cap; @@ -25,20 +25,19 @@ static int ats_alloc_one(struct pci_dev *dev, int ps) pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS); if (!pos) - return -ENODEV; + return; ats = kzalloc(sizeof(*ats), GFP_KERNEL); - if (!ats) - return -ENOMEM; + if (!ats) { + dev_warn(&dev->dev, "can't allocate space for ATS state\n"); + return; + } ats->pos = pos; - ats->stu = ps; pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap); ats->qdep = PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) : PCI_ATS_MAX_QDEP; dev->ats = ats; - - return 0; } static void ats_free_one(struct pci_dev *dev) @@ -47,6 +46,16 @@ static void ats_free_one(struct pci_dev *dev) dev->ats = NULL; } +void pci_ats_init(struct pci_dev *dev) +{ + ats_alloc_one(dev); +} + +void pci_ats_free(struct pci_dev *dev) +{ + ats_free_one(dev); +} + /** * pci_enable_ats - enable the ATS capability * @dev: the PCI device @@ -56,43 +65,35 @@ static void ats_free_one(struct pci_dev *dev) */ int pci_enable_ats(struct pci_dev *dev, int ps) { - int rc; u16 ctrl; BUG_ON(dev->ats && dev->ats->is_enabled); + if (!dev->ats) + return -EINVAL; + if (ps < PCI_ATS_MIN_STU) return -EINVAL; - if (dev->is_physfn || dev->is_virtfn) { - struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn; + /* + * Note that enabling ATS on a VF fails unless it's already enabled + * with the same STU on the PF. + */ + ctrl = PCI_ATS_CTRL_ENABLE; + if (dev->is_virtfn) { + struct pci_dev *pdev = dev->physfn; - mutex_lock(&pdev->sriov->lock); - if (pdev->ats) - rc = pdev->ats->stu == ps ? 0 : -EINVAL; - else - rc = ats_alloc_one(pdev, ps); + if (pdev->ats->stu != ps) + return -EINVAL; - if (!rc) - pdev->ats->ref_cnt++; - mutex_unlock(&pdev->sriov->lock); - if (rc) - return rc; - } - - if (!dev->is_physfn) { - rc = ats_alloc_one(dev, ps); - if (rc) - return rc; + atomic_inc(&pdev->ats->ref_cnt); /* count enabled VFs */ + } else { + dev->ats->stu = ps; + ctrl |= PCI_ATS_CTRL_STU(dev->ats->stu - PCI_ATS_MIN_STU); } - - ctrl = PCI_ATS_CTRL_ENABLE; - if (!dev->is_virtfn) - ctrl |= PCI_ATS_CTRL_STU(ps - PCI_ATS_MIN_STU); pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl); dev->ats->is_enabled = 1; - return 0; } EXPORT_SYMBOL_GPL(pci_enable_ats); @@ -107,24 +108,20 @@ void pci_disable_ats(struct pci_dev *dev) BUG_ON(!dev->ats || !dev->ats->is_enabled); + if (atomic_read(&dev->ats->ref_cnt)) + return; /* VFs still enabled */ + + if (dev->is_virtfn) { + struct pci_dev *pdev = dev->physfn; + + atomic_dec(&pdev->ats->ref_cnt); + } + pci_read_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, &ctrl); ctrl &= ~PCI_ATS_CTRL_ENABLE; pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl); dev->ats->is_enabled = 0; - - if (dev->is_physfn || dev->is_virtfn) { - struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn; - - mutex_lock(&pdev->sriov->lock); - pdev->ats->ref_cnt--; - if (!pdev->ats->ref_cnt) - ats_free_one(pdev); - mutex_unlock(&pdev->sriov->lock); - } - - if (!dev->is_physfn) - ats_free_one(dev); } EXPORT_SYMBOL_GPL(pci_disable_ats); @@ -140,7 +137,6 @@ void pci_restore_ats_state(struct pci_dev *dev) ctrl = PCI_ATS_CTRL_ENABLE; if (!dev->is_virtfn) ctrl |= PCI_ATS_CTRL_STU(dev->ats->stu - PCI_ATS_MIN_STU); - pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl); } EXPORT_SYMBOL_GPL(pci_restore_ats_state); @@ -159,23 +155,13 @@ EXPORT_SYMBOL_GPL(pci_restore_ats_state); */ int pci_ats_queue_depth(struct pci_dev *dev) { - int pos; - u16 cap; - if (dev->is_virtfn) return 0; if (dev->ats) return dev->ats->qdep; - pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS); - if (!pos) - return -ENODEV; - - pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap); - - return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) : - PCI_ATS_MAX_QDEP; + return -ENODEV; } EXPORT_SYMBOL_GPL(pci_ats_queue_depth); diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index cefd636..c206398 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1540,6 +1540,9 @@ static void pci_init_capabilities(struct pci_dev *dev) /* Single Root I/O Virtualization */ pci_iov_init(dev); + /* Address Translation Services */ + pci_ats_init(dev); + /* Enable ACS P2P upstream forwarding */ pci_enable_acs(dev); } diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c index 8a280e9..27617b8 100644 --- a/drivers/pci/remove.c +++ b/drivers/pci/remove.c @@ -26,6 +26,7 @@ static void pci_stop_dev(struct pci_dev *dev) dev->is_added = 0; } + pci_ats_free(dev); if (dev->bus->self) pcie_aspm_exit_link_state(dev); } diff --git a/include/linux/pci-ats.h b/include/linux/pci-ats.h index 7203178..e2dcc2f 100644 --- a/include/linux/pci-ats.h +++ b/include/linux/pci-ats.h @@ -8,7 +8,7 @@ struct pci_ats { int pos; /* capability position */ int stu; /* Smallest Translation Unit */ int qdep; /* Invalidate Queue Depth */ - int ref_cnt; /* Physical Function reference count */ + atomic_t ref_cnt; /* number of VFs with ATS enabled */ unsigned int is_enabled:1; /* Enable bit is set */ }; diff --git a/include/linux/pci.h b/include/linux/pci.h index 8a0321a..1817819 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1294,6 +1294,15 @@ int ht_create_irq(struct pci_dev *dev, int idx); void ht_destroy_irq(unsigned int irq); #endif /* CONFIG_HT_IRQ */ +#ifdef CONFIG_PCI_ATS +/* Address Translation Service */ +void pci_ats_init(struct pci_dev *dev); +void pci_ats_free(struct pci_dev *dev); +#else +static inline void pci_ats_init(struct pci_dev *dev) { } +static inline void pci_ats_free(struct pci_dev *dev) { } +#endif + void pci_cfg_access_lock(struct pci_dev *dev); bool pci_cfg_access_trylock(struct pci_dev *dev); void pci_cfg_access_unlock(struct pci_dev *dev);