Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756641AbaAGJAp (ORCPT ); Tue, 7 Jan 2014 04:00:45 -0500 Received: from mga11.intel.com ([192.55.52.93]:3277 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756549AbaAGJAn (ORCPT ); Tue, 7 Jan 2014 04:00:43 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.95,617,1384329600"; d="scan'208";a="454739996" From: Jiang Liu To: Joerg Roedel , David Woodhouse , Yinghai Lu , Bjorn Helgaas , Dan Williams , Vinod Koul 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 V1 10/14] iommu/vt-d: use RCU to protect global resources in interrupt context Date: Tue, 7 Jan 2014 17:00:30 +0800 Message-Id: <1389085234-22296-11-git-send-email-jiang.liu@linux.intel.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1389085234-22296-1-git-send-email-jiang.liu@linux.intel.com> References: <1389085234-22296-1-git-send-email-jiang.liu@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 | 22 ++++++++++++++++++---- include/linux/dmar.h | 30 ++++++++++++++++++++---------- 3 files changed, 58 insertions(+), 27 deletions(-) diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index 2831442..31c72d5 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 25e9b84..91ecb95 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 */ }; @@ -632,12 +632,15 @@ 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); } @@ -656,6 +659,7 @@ 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; @@ -675,6 +679,7 @@ static struct intel_iommu *device_to_iommu(int segment, u8 bus, u8 devfn) } iommu = NULL; out: + rcu_read_unlock(); return iommu; } @@ -1538,9 +1543,11 @@ static void domain_exit(struct dmar_domain *domain) /* free page tables */ dma_pte_free_pagetable(domain, 0, DOMAIN_MAX_PFN(domain->gaw)); + rcu_read_lock(); for_each_active_iommu(iommu, drhd) if (test_bit(iommu->seq_id, domain->iommu_bmp)) iommu_detach_domain(domain, iommu); + rcu_read_unlock(); free_domain_mem(domain); } @@ -2334,6 +2341,7 @@ 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 @@ -2342,9 +2350,11 @@ 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; } @@ -3506,7 +3516,7 @@ 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; } @@ -3568,6 +3578,7 @@ 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)) @@ -3582,6 +3593,7 @@ int dmar_find_matched_atsr_unit(struct pci_dev *dev) } ret = 0; out: + rcu_read_unlock(); return ret; } @@ -3598,7 +3610,7 @@ 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; @@ -3915,6 +3927,7 @@ static void iommu_free_vm_domain(struct dmar_domain *domain) unsigned long i; unsigned long ndomains; + rcu_read_lock(); for_each_active_iommu(iommu, drhd) { ndomains = cap_ndoms(iommu->cap); for_each_set_bit(i, iommu->domain_ids, ndomains) { @@ -3927,6 +3940,7 @@ static void iommu_free_vm_domain(struct dmar_domain *domain) } } } + rcu_read_unlock(); } static void vm_domain_exit(struct dmar_domain *domain) diff --git a/include/linux/dmar.h b/include/linux/dmar.h index 9572a4f..3e42960 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 @@ -76,6 +86,10 @@ extern struct list_head dmar_drhd_units; extern int dmar_table_init(void); extern int dmar_dev_scope_init(void); extern int enable_drhd_fault_handling(void); +extern void *dmar_alloc_dev_scope(void *start, void *end, int *cnt); +extern int dmar_parse_dev_scope(void *start, void *end, int *cnt, + struct pci_dev __rcu ***devices, u16 segment); +extern void dmar_free_dev_scope(struct pci_dev __rcu ***devices, int *cnt); #else static inline int dmar_table_init(void) { @@ -138,10 +152,6 @@ extern int iommu_detected, no_iommu; extern int dmar_parse_rmrr_atsr_dev(void); extern int dmar_parse_one_rmrr(struct acpi_dmar_header *header); extern int dmar_parse_one_atsr(struct acpi_dmar_header *header); -extern void *dmar_alloc_dev_scope(void *start, void *end, int *cnt); -extern int dmar_parse_dev_scope(void *start, void *end, int *cnt, - struct pci_dev ***devices, u16 segment); -extern void dmar_free_dev_scope(struct pci_dev ***devices, int *cnt); extern int intel_iommu_init(void); #else /* !CONFIG_INTEL_IOMMU: */ static inline int intel_iommu_init(void) { return -ENODEV; } -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/