Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754708AbbDJGdP (ORCPT ); Fri, 10 Apr 2015 02:33:15 -0400 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:51126 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754380AbbDJGdL (ORCPT ); Fri, 10 Apr 2015 02:33:11 -0400 From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Cc: Alexey Kardashevskiy , Benjamin Herrenschmidt , Paul Mackerras , Alex Williamson , linux-kernel@vger.kernel.org Subject: [PATCH kernel v8 28/31] powerpc/mmu: Add userspace-to-physical addresses translation cache Date: Fri, 10 Apr 2015 16:31:10 +1000 Message-Id: <1428647473-11738-29-git-send-email-aik@ozlabs.ru> X-Mailer: git-send-email 2.0.0 In-Reply-To: <1428647473-11738-1-git-send-email-aik@ozlabs.ru> References: <1428647473-11738-1-git-send-email-aik@ozlabs.ru> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15041006-0013-0000-0000-00000112F181 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9872 Lines: 338 We are adding support for DMA memory pre-registration to be used in conjunction with VFIO. The idea is that the userspace which is going to run a guest may want to pre-register a user space memory region so it all gets pinned once and never goes away. Having this done, a hypervisor will not have to pin/unpin pages on every DMA map/unmap request. This is going to help with multiple pinning of the same memory and in-kernel acceleration of DMA requests. This adds a list of memory regions to mm_context_t. Each region consists of a header and a list of physical addresses. This adds API to: 1. register/unregister memory regions; 2. do final cleanup (which puts all pre-registered pages); 3. do userspace to physical address translation; 4. manage a mapped pages counter; when it is zero, it is safe to unregister the region. Multiple registration of the same region is allowed, kref is used to track the number of registrations. Signed-off-by: Alexey Kardashevskiy --- Changes: v8: * s/mm_iommu_table_group_mem_t/struct mm_iommu_table_group_mem_t/ * fixed error fallback look (s/[i]/[j]/) --- arch/powerpc/include/asm/mmu-hash64.h | 3 + arch/powerpc/include/asm/mmu_context.h | 17 +++ arch/powerpc/mm/Makefile | 1 + arch/powerpc/mm/mmu_context_hash64.c | 6 + arch/powerpc/mm/mmu_context_hash64_iommu.c | 215 +++++++++++++++++++++++++++++ 5 files changed, 242 insertions(+) create mode 100644 arch/powerpc/mm/mmu_context_hash64_iommu.c diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h index 4f13c3e..83214c4 100644 --- a/arch/powerpc/include/asm/mmu-hash64.h +++ b/arch/powerpc/include/asm/mmu-hash64.h @@ -535,6 +535,9 @@ typedef struct { /* for 4K PTE fragment support */ void *pte_frag; #endif +#ifdef CONFIG_SPAPR_TCE_IOMMU + struct list_head iommu_group_mem_list; +#endif } mm_context_t; diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 73382eb..d6116ca 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -16,6 +16,23 @@ */ extern int init_new_context(struct task_struct *tsk, struct mm_struct *mm); extern void destroy_context(struct mm_struct *mm); +#ifdef CONFIG_SPAPR_TCE_IOMMU +struct mm_iommu_table_group_mem_t; + +extern bool mm_iommu_preregistered(void); +extern long mm_iommu_alloc(unsigned long ua, unsigned long entries, + struct mm_iommu_table_group_mem_t **pmem); +extern struct mm_iommu_table_group_mem_t *mm_iommu_get(unsigned long ua, + unsigned long entries); +extern long mm_iommu_put(struct mm_iommu_table_group_mem_t *mem); +extern void mm_iommu_cleanup(mm_context_t *ctx); +extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup(unsigned long ua, + unsigned long size); +extern long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem, + unsigned long ua, unsigned long *hpa); +extern long mm_iommu_mapped_update(struct mm_iommu_table_group_mem_t *mem, + bool inc); +#endif extern void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next); extern void switch_slb(struct task_struct *tsk, struct mm_struct *mm); diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile index 438dcd3..49fbfc7 100644 --- a/arch/powerpc/mm/Makefile +++ b/arch/powerpc/mm/Makefile @@ -35,3 +35,4 @@ obj-$(CONFIG_PPC_SUBPAGE_PROT) += subpage-prot.o obj-$(CONFIG_NOT_COHERENT_CACHE) += dma-noncoherent.o obj-$(CONFIG_HIGHMEM) += highmem.o obj-$(CONFIG_PPC_COPRO_BASE) += copro_fault.o +obj-$(CONFIG_SPAPR_TCE_IOMMU) += mmu_context_hash64_iommu.o diff --git a/arch/powerpc/mm/mmu_context_hash64.c b/arch/powerpc/mm/mmu_context_hash64.c index 178876ae..eb3080c 100644 --- a/arch/powerpc/mm/mmu_context_hash64.c +++ b/arch/powerpc/mm/mmu_context_hash64.c @@ -89,6 +89,9 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm) #ifdef CONFIG_PPC_64K_PAGES mm->context.pte_frag = NULL; #endif +#ifdef CONFIG_SPAPR_TCE_IOMMU + INIT_LIST_HEAD_RCU(&mm->context.iommu_group_mem_list); +#endif return 0; } @@ -132,6 +135,9 @@ static inline void destroy_pagetable_page(struct mm_struct *mm) void destroy_context(struct mm_struct *mm) { +#ifdef CONFIG_SPAPR_TCE_IOMMU + mm_iommu_cleanup(&mm->context); +#endif #ifdef CONFIG_PPC_ICSWX drop_cop(mm->context.acop, mm); diff --git a/arch/powerpc/mm/mmu_context_hash64_iommu.c b/arch/powerpc/mm/mmu_context_hash64_iommu.c new file mode 100644 index 0000000..af7668c --- /dev/null +++ b/arch/powerpc/mm/mmu_context_hash64_iommu.c @@ -0,0 +1,215 @@ +/* + * IOMMU helpers in MMU context. + * + * Copyright (C) 2015 IBM Corp. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + */ + +#include +#include +#include +#include +#include +#include + +struct mm_iommu_table_group_mem_t { + struct list_head next; + struct rcu_head rcu; + struct kref kref; /* one reference per VFIO container */ + atomic_t mapped; /* number of currently mapped pages */ + u64 ua; /* userspace address */ + u64 entries; /* number of entries in hpas[] */ + u64 *hpas; /* vmalloc'ed */ +}; + +bool mm_iommu_preregistered(void) +{ + if (!current || !current->mm) + return false; + + return !list_empty(¤t->mm->context.iommu_group_mem_list); +} +EXPORT_SYMBOL_GPL(mm_iommu_preregistered); + +long mm_iommu_alloc(unsigned long ua, unsigned long entries, + struct mm_iommu_table_group_mem_t **pmem) +{ + struct mm_iommu_table_group_mem_t *mem; + long i, j; + struct page *page = NULL; + + list_for_each_entry_rcu(mem, ¤t->mm->context.iommu_group_mem_list, + next) { + if ((mem->ua == ua) && (mem->entries == entries)) + return -EBUSY; + + /* Overlap? */ + if ((mem->ua < (ua + (entries << PAGE_SHIFT))) && + (ua < (mem->ua + (mem->entries << PAGE_SHIFT)))) + return -EINVAL; + } + + mem = kzalloc(sizeof(*mem), GFP_KERNEL); + if (!mem) + return -ENOMEM; + + mem->hpas = vzalloc(entries * sizeof(mem->hpas[0])); + if (!mem->hpas) { + kfree(mem); + return -ENOMEM; + } + + for (i = 0; i < entries; ++i) { + if (1 != get_user_pages_fast(ua + (i << PAGE_SHIFT), + 1/* pages */, 1/* iswrite */, &page)) { + for (j = 0; j < i; ++j) + put_page(pfn_to_page( + mem->hpas[j] >> PAGE_SHIFT)); + vfree(mem->hpas); + kfree(mem); + return -EFAULT; + } + + mem->hpas[i] = page_to_pfn(page) << PAGE_SHIFT; + } + + kref_init(&mem->kref); + atomic_set(&mem->mapped, 0); + mem->ua = ua; + mem->entries = entries; + *pmem = mem; + + list_add_rcu(&mem->next, ¤t->mm->context.iommu_group_mem_list); + + return 0; +} +EXPORT_SYMBOL_GPL(mm_iommu_alloc); + +static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem) +{ + long i; + struct page *page = NULL; + + for (i = 0; i < mem->entries; ++i) { + if (!mem->hpas[i]) + continue; + + page = pfn_to_page(mem->hpas[i] >> PAGE_SHIFT); + if (!page) + continue; + + put_page(page); + mem->hpas[i] = 0; + } +} + +static void mm_iommu_free(struct rcu_head *head) +{ + struct mm_iommu_table_group_mem_t *mem = container_of(head, + struct mm_iommu_table_group_mem_t, rcu); + + mm_iommu_unpin(mem); + vfree(mem->hpas); + kfree(mem); +} + +static void mm_iommu_release(struct kref *kref) +{ + struct mm_iommu_table_group_mem_t *mem = container_of(kref, + struct mm_iommu_table_group_mem_t, kref); + + list_del_rcu(&mem->next); + call_rcu(&mem->rcu, mm_iommu_free); +} + +struct mm_iommu_table_group_mem_t *mm_iommu_get(unsigned long ua, + unsigned long entries) +{ + struct mm_iommu_table_group_mem_t *mem; + + list_for_each_entry_rcu(mem, ¤t->mm->context.iommu_group_mem_list, + next) { + if ((mem->ua == ua) && (mem->entries == entries)) { + kref_get(&mem->kref); + return mem; + } + } + + return NULL; +} +EXPORT_SYMBOL_GPL(mm_iommu_get); + +long mm_iommu_put(struct mm_iommu_table_group_mem_t *mem) +{ + if (atomic_read(&mem->mapped)) + return -EBUSY; + + kref_put(&mem->kref, mm_iommu_release); + + return 0; +} +EXPORT_SYMBOL_GPL(mm_iommu_put); + +struct mm_iommu_table_group_mem_t *mm_iommu_lookup(unsigned long ua, + unsigned long size) +{ + struct mm_iommu_table_group_mem_t *mem, *ret = NULL; + + list_for_each_entry_rcu(mem, + ¤t->mm->context.iommu_group_mem_list, + next) { + if ((mem->ua <= ua) && + (ua + size <= mem->ua + + (mem->entries << PAGE_SHIFT))) { + ret = mem; + break; + } + } + + return ret; +} +EXPORT_SYMBOL_GPL(mm_iommu_lookup); + +long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem, + unsigned long ua, unsigned long *hpa) +{ + const long entry = (ua - mem->ua) >> PAGE_SHIFT; + u64 *va = &mem->hpas[entry]; + + if (entry >= mem->entries) + return -EFAULT; + + *hpa = *va | (ua & ~PAGE_MASK); + + return 0; +} +EXPORT_SYMBOL_GPL(mm_iommu_ua_to_hpa); + +long mm_iommu_mapped_update(struct mm_iommu_table_group_mem_t *mem, bool inc) +{ + long ret = 0; + + if (inc) + atomic_inc(&mem->mapped); + else + ret = atomic_dec_if_positive(&mem->mapped); + + return ret; +} +EXPORT_SYMBOL_GPL(mm_iommu_mapped_update); + +void mm_iommu_cleanup(mm_context_t *ctx) +{ + while (!list_empty(&ctx->iommu_group_mem_list)) { + struct mm_iommu_table_group_mem_t *mem; + + mem = list_first_entry(&ctx->iommu_group_mem_list, + struct mm_iommu_table_group_mem_t, next); + mm_iommu_release(&mem->kref); + } +} -- 2.0.0 -- 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/