From patchwork Tue May 19 06:52:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kirti Wankhede X-Patchwork-Id: 11557111 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 47D911391 for ; Tue, 19 May 2020 07:26:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1AB072075F for ; Tue, 19 May 2020 07:26:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="UqxelBSu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728159AbgESH0N (ORCPT ); Tue, 19 May 2020 03:26:13 -0400 Received: from hqnvemgate26.nvidia.com ([216.228.121.65]:7814 "EHLO hqnvemgate26.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726881AbgESH0M (ORCPT ); Tue, 19 May 2020 03:26:12 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 19 May 2020 00:25:57 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Tue, 19 May 2020 00:26:09 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Tue, 19 May 2020 00:26:09 -0700 Received: from HQMAIL105.nvidia.com (172.20.187.12) by HQMAIL105.nvidia.com (172.20.187.12) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 19 May 2020 07:26:09 +0000 Received: from kwankhede-dev.nvidia.com (10.124.1.5) by HQMAIL105.nvidia.com (172.20.187.12) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Tue, 19 May 2020 07:26:02 +0000 From: Kirti Wankhede To: , CC: , , , , , , , , , , , , , , , , , , , , Kirti Wankhede Subject: [PATCH Kernel v22 5/8] vfio iommu: Implementation of ioctl for dirty pages tracking Date: Tue, 19 May 2020 12:22:58 +0530 Message-ID: <1589871178-8282-1-git-send-email-kwankhede@nvidia.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <17511c50-dc59-d9e9-10b6-54b16dec01c4@nvidia.com> References: <17511c50-dc59-d9e9-10b6-54b16dec01c4@nvidia.com> X-NVConfidentiality: public MIME-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1589873157; bh=OTPdTfD3q2pZ56e0XbOLl0CElgEI4wot2JIWkdS4xYw=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:X-NVConfidentiality:MIME-Version: Content-Type; b=UqxelBSu4YQ+isYv1v/dTWH2DWdvcrntP5O6FzxZrjaelxSHZqBhr3udI7MFaNANt ohdRyXGndeTri/FaiixSs8PbLxygHhtJLigDJZXrUJXVqUuNhnDD3omnauCi/tEqAi WhRqISQm2qKmV8t4t/fjLnRLOkpXsPFBHOZI8FvRy920ww5zDB181cy+LLoFNvH2LI uTSCV6l5L5BAjxA11hMDHr3x+xmGB/thkPwByS6cOntsOxI/nB17bJ8mOrQjAUdK9I NtxQx9mrzSTV7TOfvXviBqd2Z1WoTqnru3ahSsKY3Vwf/jmHU/3gBjAddsrB/5qHN7 ZXXeRZGrEGEQQ== Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org VFIO_IOMMU_DIRTY_PAGES ioctl performs three operations: - Start dirty pages tracking while migration is active - Stop dirty pages tracking. - Get dirty pages bitmap. Its user space application's responsibility to copy content of dirty pages from source to destination during migration. To prevent DoS attack, memory for bitmap is allocated per vfio_dma structure. Bitmap size is calculated considering smallest supported page size. Bitmap is allocated for all vfio_dmas when dirty logging is enabled Bitmap is populated for already pinned pages when bitmap is allocated for a vfio_dma with the smallest supported page size. Update bitmap from pinning functions when tracking is enabled. When user application queries bitmap, check if requested page size is same as page size used to populated bitmap. If it is equal, copy bitmap, but if not equal, return error. Signed-off-by: Kirti Wankhede Reviewed-by: Neo Jia Fixed error reported by build bot by changing pgsize type from uint64_t to size_t. Reported-by: kbuild test robot --- drivers/vfio/vfio_iommu_type1.c | 313 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 307 insertions(+), 6 deletions(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index de17787ffece..0a420594483a 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -72,6 +72,7 @@ struct vfio_iommu { uint64_t pgsize_bitmap; bool v2; bool nesting; + bool dirty_page_tracking; }; struct vfio_domain { @@ -92,6 +93,7 @@ struct vfio_dma { bool lock_cap; /* capable(CAP_IPC_LOCK) */ struct task_struct *task; struct rb_root pfn_list; /* Ex-user pinned pfn list */ + unsigned long *bitmap; }; struct vfio_group { @@ -126,6 +128,19 @@ struct vfio_regions { #define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \ (!list_empty(&iommu->domain_list)) +#define DIRTY_BITMAP_BYTES(n) (ALIGN(n, BITS_PER_TYPE(u64)) / BITS_PER_BYTE) + +/* + * Input argument of number of bits to bitmap_set() is unsigned integer, which + * further casts to signed integer for unaligned multi-bit operation, + * __bitmap_set(). + * Then maximum bitmap size supported is 2^31 bits divided by 2^3 bits/byte, + * that is 2^28 (256 MB) which maps to 2^31 * 2^12 = 2^43 (8TB) on 4K page + * system. + */ +#define DIRTY_BITMAP_PAGES_MAX ((u64)INT_MAX) +#define DIRTY_BITMAP_SIZE_MAX DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX) + static int put_pfn(unsigned long pfn, int prot); /* @@ -176,6 +191,80 @@ static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old) rb_erase(&old->node, &iommu->dma_list); } + +static int vfio_dma_bitmap_alloc(struct vfio_dma *dma, size_t pgsize) +{ + uint64_t npages = dma->size / pgsize; + + if (npages > DIRTY_BITMAP_PAGES_MAX) + return -EINVAL; + + /* + * Allocate extra 64 bits that are used to calculate shift required for + * bitmap_shift_left() to manipulate and club unaligned number of pages + * in adjacent vfio_dma ranges. + */ + dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages) + sizeof(u64), + GFP_KERNEL); + if (!dma->bitmap) + return -ENOMEM; + + return 0; +} + +static void vfio_dma_bitmap_free(struct vfio_dma *dma) +{ + kfree(dma->bitmap); + dma->bitmap = NULL; +} + +static void vfio_dma_populate_bitmap(struct vfio_dma *dma, size_t pgsize) +{ + struct rb_node *p; + + for (p = rb_first(&dma->pfn_list); p; p = rb_next(p)) { + struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn, node); + + bitmap_set(dma->bitmap, (vpfn->iova - dma->iova) / pgsize, 1); + } +} + +static int vfio_dma_bitmap_alloc_all(struct vfio_iommu *iommu, size_t pgsize) +{ + struct rb_node *n; + + for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) { + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); + int ret; + + ret = vfio_dma_bitmap_alloc(dma, pgsize); + if (ret) { + struct rb_node *p; + + for (p = rb_prev(n); p; p = rb_prev(p)) { + struct vfio_dma *dma = rb_entry(n, + struct vfio_dma, node); + + vfio_dma_bitmap_free(dma); + } + return ret; + } + vfio_dma_populate_bitmap(dma, pgsize); + } + return 0; +} + +static void vfio_dma_bitmap_free_all(struct vfio_iommu *iommu) +{ + struct rb_node *n; + + for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) { + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); + + vfio_dma_bitmap_free(dma); + } +} + /* * Helper Functions for host iova-pfn list */ @@ -568,6 +657,17 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data, vfio_unpin_page_external(dma, iova, do_accounting); goto pin_unwind; } + + if (iommu->dirty_page_tracking) { + unsigned long pgshift = __ffs(iommu->pgsize_bitmap); + + /* + * Bitmap populated with the smallest supported page + * size + */ + bitmap_set(dma->bitmap, + (iova - dma->iova) >> pgshift, 1); + } } ret = i; @@ -802,6 +902,7 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma) vfio_unmap_unpin(iommu, dma, true); vfio_unlink_dma(iommu, dma); put_task_struct(dma->task); + vfio_dma_bitmap_free(dma); kfree(dma); iommu->dma_avail++; } @@ -829,6 +930,93 @@ static void vfio_pgsize_bitmap(struct vfio_iommu *iommu) } } +static int update_user_bitmap(u64 __user *bitmap, struct vfio_dma *dma, + dma_addr_t base_iova, size_t pgsize) +{ + unsigned long pgshift = __ffs(pgsize); + unsigned long nbits = dma->size >> pgshift; + unsigned long bit_offset = (dma->iova - base_iova) >> pgshift; + unsigned long copy_offset = bit_offset / BITS_PER_LONG; + unsigned long shift = bit_offset % BITS_PER_LONG; + unsigned long leftover; + + /* mark all pages dirty if all pages are pinned and mapped. */ + if (dma->iommu_mapped) + bitmap_set(dma->bitmap, 0, nbits); + + if (shift) { + bitmap_shift_left(dma->bitmap, dma->bitmap, shift, + nbits + shift); + + if (copy_from_user(&leftover, (u64 *)bitmap + copy_offset, + sizeof(leftover))) + return -EFAULT; + + bitmap_or(dma->bitmap, dma->bitmap, &leftover, shift); + } + + if (copy_to_user((u64 *)bitmap + copy_offset, dma->bitmap, + DIRTY_BITMAP_BYTES(nbits + shift))) + return -EFAULT; + + return 0; +} + +static int vfio_iova_dirty_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu, + dma_addr_t iova, size_t size, size_t pgsize) +{ + struct vfio_dma *dma; + struct rb_node *n; + unsigned long pgshift = __ffs(pgsize); + int ret; + + /* + * GET_BITMAP request must fully cover vfio_dma mappings. Multiple + * vfio_dma mappings may be clubbed by specifying large ranges, but + * there must not be any previous mappings bisected by the range. + * An error will be returned if these conditions are not met. + */ + dma = vfio_find_dma(iommu, iova, 1); + if (dma && dma->iova != iova) + return -EINVAL; + + dma = vfio_find_dma(iommu, iova + size - 1, 0); + if (dma && dma->iova + dma->size != iova + size) + return -EINVAL; + + for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) { + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); + + if (dma->iova < iova) + continue; + + if (dma->iova > iova + size) + break; + + ret = update_user_bitmap(bitmap, dma, iova, pgsize); + if (ret) + return ret; + + /* + * Re-populate bitmap to include all pinned pages which are + * considered as dirty but exclude pages which are unpinned and + * pages which are marked dirty by vfio_dma_rw() + */ + bitmap_clear(dma->bitmap, 0, dma->size >> pgshift); + vfio_dma_populate_bitmap(dma, pgsize); + } + return 0; +} + +static int verify_bitmap_size(uint64_t npages, uint64_t bitmap_size) +{ + if (!npages || !bitmap_size || (bitmap_size > DIRTY_BITMAP_SIZE_MAX) || + (bitmap_size < DIRTY_BITMAP_BYTES(npages))) + return -EINVAL; + + return 0; +} + static int vfio_dma_do_unmap(struct vfio_iommu *iommu, struct vfio_iommu_type1_dma_unmap *unmap) { @@ -1046,7 +1234,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, unsigned long vaddr = map->vaddr; size_t size = map->size; int ret = 0, prot = 0; - uint64_t mask; + size_t pgsize; struct vfio_dma *dma; /* Verify that none of our __u64 fields overflow */ @@ -1061,11 +1249,11 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, mutex_lock(&iommu->lock); - mask = ((uint64_t)1 << __ffs(iommu->pgsize_bitmap)) - 1; + pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap); - WARN_ON(mask & PAGE_MASK); + WARN_ON((pgsize - 1) & PAGE_MASK); - if (!prot || !size || (size | iova | vaddr) & mask) { + if (!prot || !size || (size | iova | vaddr) & (pgsize - 1)) { ret = -EINVAL; goto out_unlock; } @@ -1142,6 +1330,12 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, else ret = vfio_pin_map_dma(iommu, dma, size); + if (!ret && iommu->dirty_page_tracking) { + ret = vfio_dma_bitmap_alloc(dma, pgsize); + if (ret) + vfio_remove_dma(iommu, dma); + } + out_unlock: mutex_unlock(&iommu->lock); return ret; @@ -2288,6 +2482,104 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, return copy_to_user((void __user *)arg, &unmap, minsz) ? -EFAULT : 0; + } else if (cmd == VFIO_IOMMU_DIRTY_PAGES) { + struct vfio_iommu_type1_dirty_bitmap dirty; + uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START | + VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP | + VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP; + int ret = 0; + + if (!iommu->v2) + return -EACCES; + + minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap, + flags); + + if (copy_from_user(&dirty, (void __user *)arg, minsz)) + return -EFAULT; + + if (dirty.argsz < minsz || dirty.flags & ~mask) + return -EINVAL; + + /* only one flag should be set at a time */ + if (__ffs(dirty.flags) != __fls(dirty.flags)) + return -EINVAL; + + if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) { + size_t pgsize; + + mutex_lock(&iommu->lock); + pgsize = 1 << __ffs(iommu->pgsize_bitmap); + if (!iommu->dirty_page_tracking) { + ret = vfio_dma_bitmap_alloc_all(iommu, pgsize); + if (!ret) + iommu->dirty_page_tracking = true; + } + mutex_unlock(&iommu->lock); + return ret; + } else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP) { + mutex_lock(&iommu->lock); + if (iommu->dirty_page_tracking) { + iommu->dirty_page_tracking = false; + vfio_dma_bitmap_free_all(iommu); + } + mutex_unlock(&iommu->lock); + return 0; + } else if (dirty.flags & + VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) { + struct vfio_iommu_type1_dirty_bitmap_get range; + unsigned long pgshift; + size_t data_size = dirty.argsz - minsz; + size_t iommu_pgsize; + + if (!data_size || data_size < sizeof(range)) + return -EINVAL; + + if (copy_from_user(&range, (void __user *)(arg + minsz), + sizeof(range))) + return -EFAULT; + + if (range.iova + range.size < range.iova) + return -EINVAL; + if (!access_ok((void __user *)range.bitmap.data, + range.bitmap.size)) + return -EINVAL; + + pgshift = __ffs(range.bitmap.pgsize); + ret = verify_bitmap_size(range.size >> pgshift, + range.bitmap.size); + if (ret) + return ret; + + mutex_lock(&iommu->lock); + + iommu_pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap); + + /* allow only smallest supported pgsize */ + if (range.bitmap.pgsize != iommu_pgsize) { + ret = -EINVAL; + goto out_unlock; + } + if (range.iova & (iommu_pgsize - 1)) { + ret = -EINVAL; + goto out_unlock; + } + if (!range.size || range.size & (iommu_pgsize - 1)) { + ret = -EINVAL; + goto out_unlock; + } + + if (iommu->dirty_page_tracking) + ret = vfio_iova_dirty_bitmap(range.bitmap.data, + iommu, range.iova, range.size, + range.bitmap.pgsize); + else + ret = -EINVAL; +out_unlock: + mutex_unlock(&iommu->lock); + + return ret; + } } return -ENOTTY; @@ -2355,10 +2647,19 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu, vaddr = dma->vaddr + offset; - if (write) + if (write) { *copied = copy_to_user((void __user *)vaddr, data, count) ? 0 : count; - else + if (*copied && iommu->dirty_page_tracking) { + unsigned long pgshift = __ffs(iommu->pgsize_bitmap); + /* + * Bitmap populated with the smallest supported page + * size + */ + bitmap_set(dma->bitmap, offset >> pgshift, + *copied >> pgshift); + } + } else *copied = copy_from_user(data, (void __user *)vaddr, count) ? 0 : count; if (kthread)