From e0bf78b0f9594d47dfa7e364a9071442fc1d9445 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Wed, 19 Dec 2018 19:52:14 +1100 Subject: [PATCH] powerpc/mm/iommu/vfio_spapr_tce: Change mm_iommu_get to reference a region Normally mm_iommu_get() should add a reference and mm_iommu_put() should remove it. However historically mm_iommu_find() does the referencing and mm_iommu_get() is doing allocation and referencing. We are going to add another helper to preregister device memory so instead of having mm_iommu_new() (which pre-registers the normal memory and references the region), we need separate helpers for pre-registering and referencing. This renames: - mm_iommu_get to mm_iommu_new; - mm_iommu_find to mm_iommu_get. This changes mm_iommu_get() to reference the region so the name now reflects what it does. This removes the check for exact match from mm_iommu_new() as we want it to fail on existing regions; mm_iommu_get() should be used instead. Signed-off-by: Alexey Kardashevskiy Reviewed-by: David Gibson Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/mmu_context.h | 4 +-- arch/powerpc/mm/mmu_context_iommu.c | 19 +++++++------- drivers/vfio/vfio_iommu_spapr_tce.c | 35 +++++++++++++++++--------- 3 files changed, 34 insertions(+), 24 deletions(-) diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index e687ed31d85a..424899a7fac8 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -21,7 +21,7 @@ struct mm_iommu_table_group_mem_t; extern int isolate_lru_page(struct page *page); /* from internal.h */ extern bool mm_iommu_preregistered(struct mm_struct *mm); -extern long mm_iommu_get(struct mm_struct *mm, +extern long mm_iommu_new(struct mm_struct *mm, unsigned long ua, unsigned long entries, struct mm_iommu_table_group_mem_t **pmem); extern long mm_iommu_put(struct mm_struct *mm, @@ -32,7 +32,7 @@ extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm, unsigned long ua, unsigned long size); extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm( struct mm_struct *mm, unsigned long ua, unsigned long size); -extern struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm, +extern struct mm_iommu_table_group_mem_t *mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long entries); extern long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem, unsigned long ua, unsigned int pageshift, unsigned long *hpa); diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c index 56c2234cc6ae..ce8cc69f7901 100644 --- a/arch/powerpc/mm/mmu_context_iommu.c +++ b/arch/powerpc/mm/mmu_context_iommu.c @@ -126,7 +126,7 @@ static int mm_iommu_move_page_from_cma(struct page *page) return 0; } -long mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long entries, +long mm_iommu_new(struct mm_struct *mm, unsigned long ua, unsigned long entries, struct mm_iommu_table_group_mem_t **pmem) { struct mm_iommu_table_group_mem_t *mem; @@ -140,12 +140,6 @@ long mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long entries, list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) { - if ((mem->ua == ua) && (mem->entries == entries)) { - ++mem->used; - *pmem = mem; - goto unlock_exit; - } - /* Overlap? */ if ((mem->ua < (ua + (entries << PAGE_SHIFT))) && (ua < (mem->ua + @@ -252,7 +246,7 @@ long mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long entries, return ret; } -EXPORT_SYMBOL_GPL(mm_iommu_get); +EXPORT_SYMBOL_GPL(mm_iommu_new); static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem) { @@ -368,21 +362,26 @@ struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(struct mm_struct *mm, return ret; } -struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm, +struct mm_iommu_table_group_mem_t *mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long entries) { struct mm_iommu_table_group_mem_t *mem, *ret = NULL; + mutex_lock(&mem_list_mutex); + list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) { if ((mem->ua == ua) && (mem->entries == entries)) { ret = mem; + ++mem->used; break; } } + mutex_unlock(&mem_list_mutex); + return ret; } -EXPORT_SYMBOL_GPL(mm_iommu_find); +EXPORT_SYMBOL_GPL(mm_iommu_get); long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem, unsigned long ua, unsigned int pageshift, unsigned long *hpa) diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c index ad637250938d..1d8b88928329 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -152,11 +152,12 @@ static long tce_iommu_unregister_pages(struct tce_container *container, struct mm_iommu_table_group_mem_t *mem; struct tce_iommu_prereg *tcemem; bool found = false; + long ret; if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK)) return -EINVAL; - mem = mm_iommu_find(container->mm, vaddr, size >> PAGE_SHIFT); + mem = mm_iommu_get(container->mm, vaddr, size >> PAGE_SHIFT); if (!mem) return -ENOENT; @@ -168,9 +169,13 @@ static long tce_iommu_unregister_pages(struct tce_container *container, } if (!found) - return -ENOENT; + ret = -ENOENT; + else + ret = tce_iommu_prereg_free(container, tcemem); - return tce_iommu_prereg_free(container, tcemem); + mm_iommu_put(container->mm, mem); + + return ret; } static long tce_iommu_register_pages(struct tce_container *container, @@ -185,22 +190,24 @@ static long tce_iommu_register_pages(struct tce_container *container, ((vaddr + size) < vaddr)) return -EINVAL; - mem = mm_iommu_find(container->mm, vaddr, entries); + mem = mm_iommu_get(container->mm, vaddr, entries); if (mem) { list_for_each_entry(tcemem, &container->prereg_list, next) { - if (tcemem->mem == mem) - return -EBUSY; + if (tcemem->mem == mem) { + ret = -EBUSY; + goto put_exit; + } } + } else { + ret = mm_iommu_new(container->mm, vaddr, entries, &mem); + if (ret) + return ret; } - ret = mm_iommu_get(container->mm, vaddr, entries, &mem); - if (ret) - return ret; - tcemem = kzalloc(sizeof(*tcemem), GFP_KERNEL); if (!tcemem) { - mm_iommu_put(container->mm, mem); - return -ENOMEM; + ret = -ENOMEM; + goto put_exit; } tcemem->mem = mem; @@ -209,6 +216,10 @@ static long tce_iommu_register_pages(struct tce_container *container, container->enabled = true; return 0; + +put_exit: + mm_iommu_put(container->mm, mem); + return ret; } static bool tce_page_is_contained(struct page *page, unsigned page_shift)