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author | Daniel Jordan <daniel.m.jordan@oracle.com> | 2021-02-19 17:13:04 +0100 |
---|---|---|
committer | Alex Williamson <alex.williamson@redhat.com> | 2021-02-23 00:30:45 +0100 |
commit | 4b6c33b3229678e38a6b0bbd4367d4b91366b523 (patch) | |
tree | 82bf0d6ab4a9899bb5293ae4067a675f9e2740f9 /drivers/vfio | |
parent | vfio/type1: Change success value of vaddr_get_pfn() (diff) | |
download | linux-4b6c33b3229678e38a6b0bbd4367d4b91366b523.tar.xz linux-4b6c33b3229678e38a6b0bbd4367d4b91366b523.zip |
vfio/type1: Prepare for batched pinning with struct vfio_batch
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@oracle.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
-rw-r--r-- | drivers/vfio/vfio_iommu_type1.c | 71 |
1 files changed, 58 insertions, 13 deletions
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 82ed8bf34c11..1c86375aca2d 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -103,6 +103,12 @@ 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; @@ -459,6 +465,31 @@ 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) @@ -499,10 +530,10 @@ 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; @@ -511,10 +542,10 @@ 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; } @@ -602,7 +633,7 @@ static int vfio_wait_all_valid(struct vfio_iommu *iommu) */ 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; @@ -613,7 +644,8 @@ 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; @@ -640,7 +672,8 @@ 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; @@ -703,6 +736,7 @@ 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; @@ -710,7 +744,7 @@ 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) { @@ -1404,15 +1438,19 @@ 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; @@ -1432,6 +1470,7 @@ 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) @@ -1608,6 +1647,7 @@ 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; @@ -1622,6 +1662,8 @@ 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)) { @@ -1669,7 +1711,8 @@ 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; @@ -1702,6 +1745,7 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu, dma->iommu_mapped = true; } + vfio_batch_fini(&batch); return 0; unwind: @@ -1742,6 +1786,7 @@ unwind: } } + vfio_batch_fini(&batch); return ret; } |