Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932669AbbELIxQ (ORCPT ); Tue, 12 May 2015 04:53:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54306 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932251AbbELIxK (ORCPT ); Tue, 12 May 2015 04:53:10 -0400 Date: Tue, 12 May 2015 16:52:54 +0800 From: Dave Young To: "Li, Zhen-Hua" Cc: dwmw2@infradead.org, indou.takao@jp.fujitsu.com, bhe@redhat.com, joro@8bytes.org, vgoyal@redhat.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, kexec@lists.infradead.org, alex.williamson@redhat.com, ddutile@redhat.com, ishii.hironobu@jp.fujitsu.com, bhelgaas@google.com, doug.hatch@hp.com, jerry.hoemann@hp.com, tom.vaden@hp.com, li.zhang6@hp.com, lisa.mitchell@hp.com, billsumnerlinux@gmail.com, rwright@hp.com Subject: Re: [PATCH v11 07/10] iommu/vt-d: enable kdump support in iommu module Message-ID: <20150512085254.GG4561@localhost.localdomain> References: <1431337974-545-1-git-send-email-zhen-hual@hp.com> <1431337974-545-8-git-send-email-zhen-hual@hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1431337974-545-8-git-send-email-zhen-hual@hp.com> User-Agent: Mutt/1.5.22.1-rc1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7489 Lines: 239 On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote: > Modify the operation of the following functions when called during crash dump: > iommu_context_addr > free_context_table > get_domain_for_dev > init_dmars > intel_iommu_init > > Bill Sumner: > Original version. > > Zhenhua: > The name of new calling functions. > Do not disable and re-enable TE in kdump kernel. > Use the did and gaw from old context entry; > > Signed-off-by: Bill Sumner > Signed-off-by: Li, Zhen-Hua > --- > drivers/iommu/intel-iommu.c | 95 +++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 83 insertions(+), 12 deletions(-) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 28c3c64..91545bf 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -397,6 +397,7 @@ static int copy_root_entry_table(struct intel_iommu *iommu); > static int intel_iommu_load_translation_tables(struct intel_iommu *iommu); > > static void iommu_check_pre_te_status(struct intel_iommu *iommu); > +static u8 g_translation_pre_enabled; > > /* > * This domain is a statically identity mapping domain. > @@ -794,6 +795,9 @@ static inline struct context_entry *iommu_context_addr(struct intel_iommu *iommu > phy_addr = virt_to_phys((void *)context); > *entry = phy_addr | 1; > __iommu_flush_cache(iommu, entry, sizeof(*entry)); > + > + if (iommu->pre_enabled_trans) > + __iommu_update_old_root_entry(iommu, bus); > } > return &context[devfn]; > } > @@ -887,13 +891,15 @@ static void clear_context_table(struct intel_iommu *iommu, u8 bus, u8 devfn) > > static void free_context_table(struct intel_iommu *iommu) > { > + struct root_entry *root = NULL; > int i; > unsigned long flags; > struct context_entry *context; > > spin_lock_irqsave(&iommu->lock, flags); > if (!iommu->root_entry) { > - goto out; > + spin_unlock_irqrestore(&iommu->lock, flags); > + return; > } > for (i = 0; i < ROOT_ENTRY_NR; i++) { > context = iommu_context_addr(iommu, i, 0, 0); > @@ -908,10 +914,23 @@ static void free_context_table(struct intel_iommu *iommu) > free_pgtable_page(context); > > } > + > + if (iommu->pre_enabled_trans) { > + iommu->root_entry_old_phys = 0; > + root = iommu->root_entry_old_virt; > + iommu->root_entry_old_virt = NULL; > + } > + > free_pgtable_page(iommu->root_entry); > iommu->root_entry = NULL; > -out: > + > spin_unlock_irqrestore(&iommu->lock, flags); > + > + /* We put this out of spin_unlock is because iounmap() may > + * cause error if surrounded by spin_lock and unlock; > + */ > + if (iommu->pre_enabled_trans) > + iounmap(root); > } > > static struct dma_pte *pfn_to_dma_pte(struct dmar_domain *domain, > @@ -2333,6 +2352,7 @@ static struct dmar_domain *get_domain_for_dev(struct device *dev, int gaw) > unsigned long flags; > u8 bus, devfn; > int did = -1; /* Default to "no domain_id supplied" */ > + struct context_entry *ce = NULL; > > domain = find_domain(dev); > if (domain) > @@ -2366,6 +2386,20 @@ static struct dmar_domain *get_domain_for_dev(struct device *dev, int gaw) > domain = alloc_domain(0); > if (!domain) > return NULL; > + > + if (iommu->pre_enabled_trans) { > + /* > + * if this device had a did in the old kernel > + * use its values instead of generating new ones > + */ > + ce = device_to_existing_context_entry(iommu, bus, devfn); > + > + if (ce) { > + did = context_domain_id(ce); > + gaw = agaw_to_width(context_address_width(ce)); > + } > + } > + > domain->id = iommu_attach_domain_with_id(domain, iommu, did); > if (domain->id < 0) { > free_domain_mem(domain); > @@ -2897,6 +2931,7 @@ static int __init init_dmars(void) > goto free_g_iommus; > } > > + g_translation_pre_enabled = 0; /* To know whether to skip RMRR */ > for_each_active_iommu(iommu, drhd) { > g_iommus[iommu->seq_id] = iommu; > > @@ -2904,14 +2939,30 @@ static int __init init_dmars(void) > if (ret) > goto free_iommu; > > - /* > - * TBD: > - * we could share the same root & context tables > - * among all IOMMU's. Need to Split it later. > - */ > - ret = iommu_alloc_root_entry(iommu); > - if (ret) > - goto free_iommu; > + iommu_check_pre_te_status(iommu); > + if (iommu->pre_enabled_trans) { > + pr_info("IOMMU Copying translate tables from panicked kernel\n"); > + ret = intel_iommu_load_translation_tables(iommu); > + if (ret) { > + pr_err("IOMMU: Copy translate tables failed\n"); > + > + /* Best to stop trying */ > + goto free_iommu; > + } > + pr_info("IOMMU: root_cache:0x%12.12llx phys:0x%12.12llx\n", > + (u64)iommu->root_entry, > + (u64)iommu->root_entry_old_phys); > + } else { > + /* > + * TBD: > + * we could share the same root & context tables > + * among all IOMMU's. Need to Split it later. > + */ > + ret = iommu_alloc_root_entry(iommu); > + if (ret) > + goto free_iommu; > + } > + > if (!ecap_pass_through(iommu->ecap)) > hw_pass_through = 0; > } > @@ -2929,6 +2980,14 @@ static int __init init_dmars(void) > check_tylersburg_isoch(); > > /* > + * In the second kernel: Skip setting-up new domains for Use kexec kernel instead of second kernel is better because there's no context reader will be confused. > + * si, rmrr, and the isa bus on the expectation that these > + * translations were copied from the old kernel. > + */ > + if (g_translation_pre_enabled) > + goto skip_new_domains_for_si_rmrr_isa; > + > + /* > * If pass through is not set or not enabled, setup context entries for > * identity mappings for rmrr, gfx, and isa and may fall back to static > * identity mapping if iommu_identity_mapping is set. > @@ -2968,6 +3027,8 @@ static int __init init_dmars(void) > > iommu_prepare_isa(); > > +skip_new_domains_for_si_rmrr_isa:; > + > /* > * for each drhd > * enable fault log > @@ -2996,7 +3057,13 @@ static int __init init_dmars(void) > > iommu->flush.flush_context(iommu, 0, 0, 0, DMA_CCMD_GLOBAL_INVL); > iommu->flush.flush_iotlb(iommu, 0, 0, 0, DMA_TLB_GLOBAL_FLUSH); > - iommu_enable_translation(iommu); > + > + if (iommu->pre_enabled_trans) { > + if (!(iommu->gcmd & DMA_GCMD_TE)) > + iommu_enable_translation(iommu); > + } else > + iommu_enable_translation(iommu); > + > iommu_disable_protect_mem_regions(iommu); > } > > @@ -4282,11 +4349,14 @@ int __init intel_iommu_init(void) > } > > /* > - * Disable translation if already enabled prior to OS handover. > + * We do not need to disable translation if already enabled prior > + * to OS handover. Because we will try to copy old tables; > */ > + /* > for_each_active_iommu(iommu, drhd) > if (iommu->gcmd & DMA_GCMD_TE) > iommu_disable_translation(iommu); > + */ Above commented out code is useless? > > if (dmar_dev_scope_init() < 0) { > if (force_on) > @@ -5106,5 +5176,6 @@ static void iommu_check_pre_te_status(struct intel_iommu *iommu) > if (sts & DMA_GSTS_TES) { > pr_info("Translation is enabled prior to OS.\n"); > iommu->pre_enabled_trans = 1; > + g_translation_pre_enabled = 1; > } > } > -- > 2.0.0-rc0 > -- 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/