This is a note to let you know that I've just added the patch titled vfio/type1: Prepare for batched pinning with struct vfio_batch to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: vfio-type1-prepare-for-batched-pinning-with-struct-v.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 50a5be8af5e4cad083f350e90abe6477bc28a963 Author: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> Date: Fri Feb 19 11:13:04 2021 -0500 vfio/type1: Prepare for batched pinning with struct vfio_batch [ Upstream commit 4b6c33b3229678e38a6b0bbd4367d4b91366b523 ] Get ready to pin more pages at once with struct vfio_batch, which represents a batch of pinned pages. The struct has a fallback page pointer to avoid two unlikely scenarios: pointlessly allocating a page if disable_hugepages is enabled or failing the whole pinning operation if the kernel can't allocate memory. vaddr_get_pfn() becomes vaddr_get_pfns() to prepare for handling multiple pages, though for now only one page is stored in the pages array. Signed-off-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx> Stable-dep-of: 873aefb376bb ("vfio/type1: Unpin zero pages") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 2d26244f9c32..0c15cffd5ef1 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -98,6 +98,12 @@ struct vfio_dma { unsigned long *bitmap; }; +struct vfio_batch { + struct page **pages; /* for pin_user_pages_remote */ + struct page *fallback_page; /* if pages alloc fails */ + int capacity; /* length of pages array */ +}; + struct vfio_group { struct iommu_group *iommu_group; struct list_head next; @@ -428,6 +434,31 @@ static int put_pfn(unsigned long pfn, int prot) return 0; } +#define VFIO_BATCH_MAX_CAPACITY (PAGE_SIZE / sizeof(struct page *)) + +static void vfio_batch_init(struct vfio_batch *batch) +{ + if (unlikely(disable_hugepages)) + goto fallback; + + batch->pages = (struct page **) __get_free_page(GFP_KERNEL); + if (!batch->pages) + goto fallback; + + batch->capacity = VFIO_BATCH_MAX_CAPACITY; + return; + +fallback: + batch->pages = &batch->fallback_page; + batch->capacity = 1; +} + +static void vfio_batch_fini(struct vfio_batch *batch) +{ + if (batch->capacity == VFIO_BATCH_MAX_CAPACITY) + free_page((unsigned long)batch->pages); +} + static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm, unsigned long vaddr, unsigned long *pfn, bool write_fault) @@ -468,10 +499,10 @@ static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm, * Returns the positive number of pfns successfully obtained or a negative * error code. */ -static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, - int prot, unsigned long *pfn) +static int vaddr_get_pfns(struct mm_struct *mm, unsigned long vaddr, + long npages, int prot, unsigned long *pfn, + struct page **pages) { - struct page *page[1]; struct vm_area_struct *vma; unsigned int flags = 0; int ret; @@ -480,10 +511,10 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, flags |= FOLL_WRITE; mmap_read_lock(mm); - ret = pin_user_pages_remote(mm, vaddr, 1, flags | FOLL_LONGTERM, - page, NULL, NULL); - if (ret == 1) { - *pfn = page_to_pfn(page[0]); + ret = pin_user_pages_remote(mm, vaddr, npages, flags | FOLL_LONGTERM, + pages, NULL, NULL); + if (ret > 0) { + *pfn = page_to_pfn(pages[0]); goto done; } @@ -516,7 +547,7 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, */ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr, long npage, unsigned long *pfn_base, - unsigned long limit) + unsigned long limit, struct vfio_batch *batch) { unsigned long pfn = 0; long ret, pinned = 0, lock_acct = 0; @@ -527,7 +558,8 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr, if (!current->mm) return -ENODEV; - ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, pfn_base); + ret = vaddr_get_pfns(current->mm, vaddr, 1, dma->prot, pfn_base, + batch->pages); if (ret < 0) return ret; @@ -554,7 +586,8 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr, /* Lock all the consecutive pages from pfn_base */ for (vaddr += PAGE_SIZE, iova += PAGE_SIZE; pinned < npage; pinned++, vaddr += PAGE_SIZE, iova += PAGE_SIZE) { - ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, &pfn); + ret = vaddr_get_pfns(current->mm, vaddr, 1, dma->prot, &pfn, + batch->pages); if (ret < 0) break; @@ -617,6 +650,7 @@ static long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova, static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr, unsigned long *pfn_base, bool do_accounting) { + struct page *pages[1]; struct mm_struct *mm; int ret; @@ -624,7 +658,7 @@ static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr, if (!mm) return -ENODEV; - ret = vaddr_get_pfn(mm, vaddr, dma->prot, pfn_base); + ret = vaddr_get_pfns(mm, vaddr, 1, dma->prot, pfn_base, pages); if (ret == 1 && do_accounting && !is_invalid_reserved_pfn(*pfn_base)) { ret = vfio_lock_acct(dma, 1, true); if (ret) { @@ -1270,15 +1304,19 @@ static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma, { dma_addr_t iova = dma->iova; unsigned long vaddr = dma->vaddr; + struct vfio_batch batch; size_t size = map_size; long npage; unsigned long pfn, limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; int ret = 0; + vfio_batch_init(&batch); + while (size) { /* Pin a contiguous chunk of memory */ npage = vfio_pin_pages_remote(dma, vaddr + dma->size, - size >> PAGE_SHIFT, &pfn, limit); + size >> PAGE_SHIFT, &pfn, limit, + &batch); if (npage <= 0) { WARN_ON(!npage); ret = (int)npage; @@ -1298,6 +1336,7 @@ static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma, dma->size += npage << PAGE_SHIFT; } + vfio_batch_fini(&batch); dma->iommu_mapped = true; if (ret) @@ -1456,6 +1495,7 @@ static int vfio_bus_type(struct device *dev, void *data) static int vfio_iommu_replay(struct vfio_iommu *iommu, struct vfio_domain *domain) { + struct vfio_batch batch; struct vfio_domain *d = NULL; struct rb_node *n; unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; @@ -1466,6 +1506,8 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu, d = list_first_entry(&iommu->domain_list, struct vfio_domain, next); + vfio_batch_init(&batch); + n = rb_first(&iommu->dma_list); for (; n; n = rb_next(n)) { @@ -1513,7 +1555,8 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu, npage = vfio_pin_pages_remote(dma, vaddr, n >> PAGE_SHIFT, - &pfn, limit); + &pfn, limit, + &batch); if (npage <= 0) { WARN_ON(!npage); ret = (int)npage; @@ -1546,6 +1589,7 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu, dma->iommu_mapped = true; } + vfio_batch_fini(&batch); return 0; unwind: @@ -1586,6 +1630,7 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu, } } + vfio_batch_fini(&batch); return ret; }