From patchwork Wed Feb 19 06:07:34 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiang Liu X-Patchwork-Id: 3678311 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: patchwork-linux-pci@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id CED469F35F for ; Wed, 19 Feb 2014 06:09:31 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id BC2B720117 for ; Wed, 19 Feb 2014 06:09:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 84CE0200D6 for ; Wed, 19 Feb 2014 06:09:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751100AbaBSGJH (ORCPT ); Wed, 19 Feb 2014 01:09:07 -0500 Received: from mga09.intel.com ([134.134.136.24]:18482 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752575AbaBSGHs (ORCPT ); Wed, 19 Feb 2014 01:07:48 -0500 Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP; 18 Feb 2014 22:03:29 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,504,1389772800"; d="scan'208";a="485626729" Received: from gerry-dev.bj.intel.com ([10.238.158.74]) by orsmga002.jf.intel.com with ESMTP; 18 Feb 2014 22:07:44 -0800 From: Jiang Liu To: Joerg Roedel , David Woodhouse , Yinghai Lu , Bjorn Helgaas , Dan Williams , Vinod Koul , "Rafael J . Wysocki" Cc: Jiang Liu , Ashok Raj , Yijing Wang , Tony Luck , iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org Subject: [Patch Part2 V2 14/17] iommu/vt-d: use RCU to protect global resources in interrupt context Date: Wed, 19 Feb 2014 14:07:34 +0800 Message-Id: <1392790057-32434-15-git-send-email-jiang.liu@linux.intel.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1392790057-32434-1-git-send-email-jiang.liu@linux.intel.com> References: <1392790057-32434-1-git-send-email-jiang.liu@linux.intel.com> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Spam-Status: No, score=-4.6 required=5.0 tests=BAYES_00,KHOP_BIG_TO_CC, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, 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 Global DMA and interrupt remapping resources may be accessed in interrupt context, so use RCU instead of rwsem to protect them in such cases. Signed-off-by: Jiang Liu --- drivers/iommu/dmar.c | 33 ++++++++++++++++++++------------- drivers/iommu/intel-iommu.c | 20 ++++++++++++++++---- include/linux/dmar.h | 23 +++++++++++++++++------ 3 files changed, 53 insertions(+), 23 deletions(-) diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index c9aca88..6e4d851 100644 --- a/drivers/iommu/dmar.c +++ b/drivers/iommu/dmar.c @@ -71,13 +71,13 @@ static void __init dmar_register_drhd_unit(struct dmar_drhd_unit *drhd) * the very end. */ if (drhd->include_all) - list_add_tail(&drhd->list, &dmar_drhd_units); + list_add_tail_rcu(&drhd->list, &dmar_drhd_units); else - list_add(&drhd->list, &dmar_drhd_units); + list_add_rcu(&drhd->list, &dmar_drhd_units); } static int __init dmar_parse_one_dev_scope(struct acpi_dmar_device_scope *scope, - struct pci_dev **dev, u16 segment) + struct pci_dev __rcu **dev, u16 segment) { struct pci_bus *bus; struct pci_dev *pdev = NULL; @@ -122,7 +122,9 @@ static int __init dmar_parse_one_dev_scope(struct acpi_dmar_device_scope *scope, pci_name(pdev)); return -EINVAL; } - *dev = pdev; + + rcu_assign_pointer(*dev, pdev); + return 0; } @@ -149,7 +151,7 @@ void *dmar_alloc_dev_scope(void *start, void *end, int *cnt) } int __init dmar_parse_dev_scope(void *start, void *end, int *cnt, - struct pci_dev ***devices, u16 segment) + struct pci_dev __rcu ***devices, u16 segment) { struct acpi_dmar_device_scope *scope; int index, ret; @@ -177,7 +179,7 @@ int __init dmar_parse_dev_scope(void *start, void *end, int *cnt, return 0; } -void dmar_free_dev_scope(struct pci_dev ***devices, int *cnt) +void dmar_free_dev_scope(struct pci_dev __rcu ***devices, int *cnt) { int i; struct pci_dev *tmp_dev; @@ -186,9 +188,10 @@ void dmar_free_dev_scope(struct pci_dev ***devices, int *cnt) for_each_active_dev_scope(*devices, *cnt, i, tmp_dev) pci_dev_put(tmp_dev); kfree(*devices); - *devices = NULL; - *cnt = 0; } + + *devices = NULL; + *cnt = 0; } /** @@ -410,7 +413,7 @@ parse_dmar_table(void) return ret; } -static int dmar_pci_device_match(struct pci_dev *devices[], int cnt, +static int dmar_pci_device_match(struct pci_dev __rcu *devices[], int cnt, struct pci_dev *dev) { int index; @@ -431,11 +434,12 @@ static int dmar_pci_device_match(struct pci_dev *devices[], int cnt, struct dmar_drhd_unit * dmar_find_matched_drhd_unit(struct pci_dev *dev) { - struct dmar_drhd_unit *dmaru = NULL; + struct dmar_drhd_unit *dmaru; struct acpi_dmar_hardware_unit *drhd; dev = pci_physfn(dev); + rcu_read_lock(); for_each_drhd_unit(dmaru) { drhd = container_of(dmaru->hdr, struct acpi_dmar_hardware_unit, @@ -443,14 +447,17 @@ dmar_find_matched_drhd_unit(struct pci_dev *dev) if (dmaru->include_all && drhd->segment == pci_domain_nr(dev->bus)) - return dmaru; + goto out; if (dmar_pci_device_match(dmaru->devices, dmaru->devices_cnt, dev)) - return dmaru; + goto out; } + dmaru = NULL; +out: + rcu_read_unlock(); - return NULL; + return dmaru; } int __init dmar_dev_scope_init(void) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 50d639a..e1679a6 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -385,14 +385,14 @@ struct dmar_rmrr_unit { struct acpi_dmar_header *hdr; /* ACPI header */ u64 base_address; /* reserved base address*/ u64 end_address; /* reserved end address */ - struct pci_dev **devices; /* target devices */ + struct pci_dev __rcu **devices; /* target devices */ int devices_cnt; /* target device count */ }; struct dmar_atsr_unit { struct list_head list; /* list of ATSR units */ struct acpi_dmar_header *hdr; /* ACPI header */ - struct pci_dev **devices; /* target devices */ + struct pci_dev __rcu **devices; /* target devices */ int devices_cnt; /* target device count */ u8 include_all:1; /* include all ports */ }; @@ -634,12 +634,15 @@ static void domain_update_iommu_superpage(struct dmar_domain *domain) } /* set iommu_superpage to the smallest common denominator */ + rcu_read_lock(); for_each_active_iommu(iommu, drhd) { mask &= cap_super_page_val(iommu->cap); if (!mask) { break; } } + rcu_read_unlock(); + domain->iommu_superpage = fls(mask); } @@ -658,6 +661,7 @@ static struct intel_iommu *device_to_iommu(int segment, u8 bus, u8 devfn) struct pci_dev *dev; int i; + rcu_read_lock(); for_each_active_iommu(iommu, drhd) { if (segment != drhd->segment) continue; @@ -677,6 +681,7 @@ static struct intel_iommu *device_to_iommu(int segment, u8 bus, u8 devfn) } iommu = NULL; out: + rcu_read_unlock(); return iommu; } @@ -1535,10 +1540,12 @@ static void domain_exit(struct dmar_domain *domain) dma_pte_free_pagetable(domain, 0, DOMAIN_MAX_PFN(domain->gaw)); /* clear attached or cached domains */ + rcu_read_lock(); for_each_active_iommu(iommu, drhd) if (domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE || test_bit(iommu->seq_id, domain->iommu_bmp)) iommu_detach_domain(domain, iommu); + rcu_read_unlock(); free_domain_mem(domain); } @@ -2338,6 +2345,7 @@ static bool device_has_rmrr(struct pci_dev *dev) struct pci_dev *tmp; int i; + rcu_read_lock(); for_each_rmrr_units(rmrr) { /* * Return TRUE if this RMRR contains the device that @@ -2346,9 +2354,11 @@ static bool device_has_rmrr(struct pci_dev *dev) for_each_active_dev_scope(rmrr->devices, rmrr->devices_cnt, i, tmp) if (tmp == dev) { + rcu_read_unlock(); return true; } } + rcu_read_unlock(); return false; } @@ -3512,7 +3522,7 @@ int __init dmar_parse_one_atsr(struct acpi_dmar_header *hdr) atsru->hdr = hdr; atsru->include_all = atsr->flags & 0x1; - list_add(&atsru->list, &dmar_atsr_units); + list_add_rcu(&atsru->list, &dmar_atsr_units); return 0; } @@ -3574,6 +3584,7 @@ int dmar_find_matched_atsr_unit(struct pci_dev *dev) if (!bridge) return 0; + rcu_read_lock(); list_for_each_entry_rcu(atsru, &dmar_atsr_units, list) { atsr = container_of(atsru->hdr, struct acpi_dmar_atsr, header); if (atsr->segment != pci_domain_nr(dev->bus)) @@ -3588,6 +3599,7 @@ int dmar_find_matched_atsr_unit(struct pci_dev *dev) } ret = 0; out: + rcu_read_unlock(); return ret; } @@ -3604,7 +3616,7 @@ int __init dmar_parse_rmrr_atsr_dev(void) return ret; } - list_for_each_entry(atsr, &dmar_atsr_units, list) { + list_for_each_entry_rcu(atsr, &dmar_atsr_units, list) { ret = atsr_parse_dev(atsr); if (ret) return ret; diff --git a/include/linux/dmar.h b/include/linux/dmar.h index 8f06a01..bedebab 100644 --- a/include/linux/dmar.h +++ b/include/linux/dmar.h @@ -26,6 +26,7 @@ #include #include #include +#include struct acpi_dmar_header; @@ -41,7 +42,7 @@ struct dmar_drhd_unit { struct list_head list; /* list of drhd units */ struct acpi_dmar_header *hdr; /* ACPI header */ u64 reg_base_addr; /* register base address*/ - struct pci_dev **devices; /* target device array */ + struct pci_dev __rcu **devices;/* target device array */ int devices_cnt; /* target device count */ u16 segment; /* PCI domain */ u8 ignored:1; /* ignore drhd */ @@ -53,22 +54,31 @@ extern struct rw_semaphore dmar_global_lock; extern struct list_head dmar_drhd_units; #define for_each_drhd_unit(drhd) \ - list_for_each_entry(drhd, &dmar_drhd_units, list) + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) #define for_each_active_drhd_unit(drhd) \ - list_for_each_entry(drhd, &dmar_drhd_units, list) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ if (drhd->ignored) {} else #define for_each_active_iommu(i, drhd) \ - list_for_each_entry(drhd, &dmar_drhd_units, list) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ if (i=drhd->iommu, drhd->ignored) {} else #define for_each_iommu(i, drhd) \ - list_for_each_entry(drhd, &dmar_drhd_units, list) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ if (i=drhd->iommu, 0) {} else +static inline bool dmar_rcu_check(void) +{ + return rwsem_is_locked(&dmar_global_lock) || + system_state == SYSTEM_BOOTING; +} + +#define dmar_rcu_dereference(p) rcu_dereference_check((p), dmar_rcu_check()) + #define for_each_dev_scope(a, c, p, d) \ - for ((p) = 0; ((d) = (p) < (c) ? (a)[(p)] : NULL, (p) < (c)); (p)++) + for ((p) = 0; ((d) = (p) < (c) ? dmar_rcu_dereference((a)[(p)]) : \ + NULL, (p) < (c)); (p)++) #define for_each_active_dev_scope(a, c, p, d) \ for_each_dev_scope((a), (c), (p), (d)) if (!(d)) { continue; } else @@ -78,6 +88,7 @@ extern int dmar_dev_scope_init(void); extern int dmar_parse_dev_scope(void *start, void *end, int *cnt, struct pci_dev ***devices, u16 segment); extern void *dmar_alloc_dev_scope(void *start, void *end, int *cnt); +extern void dmar_free_dev_scope(struct pci_dev __rcu ***devices, int *cnt); extern void dmar_free_dev_scope(struct pci_dev ***devices, int *cnt); /* Intel IOMMU detection */