From patchwork Mon May 18 05:56:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kirti Wankhede X-Patchwork-Id: 11554801 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 AF3CE913 for ; Mon, 18 May 2020 06:30:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 929AE2070A for ; Mon, 18 May 2020 06:30:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="m39hYO8g" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727779AbgERGac (ORCPT ); Mon, 18 May 2020 02:30:32 -0400 Received: from hqnvemgate26.nvidia.com ([216.228.121.65]:12614 "EHLO hqnvemgate26.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726717AbgERGac (ORCPT ); Mon, 18 May 2020 02:30:32 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Sun, 17 May 2020 23:30:19 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Sun, 17 May 2020 23:30:31 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Sun, 17 May 2020 23:30:31 -0700 Received: from HQMAIL105.nvidia.com (172.20.187.12) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 18 May 2020 06:30:31 +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; Mon, 18 May 2020 06:30:24 +0000 From: Kirti Wankhede To: , CC: , , , , , , , , , , , , , , , , , , , , "Kirti Wankhede" Subject: [PATCH Kernel v22 6/8] vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before unmap Date: Mon, 18 May 2020 11:26:35 +0530 Message-ID: <1589781397-28368-7-git-send-email-kwankhede@nvidia.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1589781397-28368-1-git-send-email-kwankhede@nvidia.com> References: <1589781397-28368-1-git-send-email-kwankhede@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=1589783419; bh=Qj1Z9E4ALTe3OijcIlgT2muMIF0yTZ1xPuY6HcUsd7U=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:X-NVConfidentiality:MIME-Version: Content-Type; b=m39hYO8gbdEkP0fjWhfh8BVie7FNpFFRG26uHaFqDB+sa1uvU0n4H+KkZk2O9yghv GUAD3YaOL5H36hIMvftCiYz+LOgsYlmhm+47kIVomJcJ6WTn2eByBZ+DQBbNNKTWkz y5kXRWrOSco9sYZ7Xs9yRyqy1nJLc1qWVlYOhNHSyOWyR5YGdYcjqx0/54eDZ0qyQd GsyzFMLyHoScpWR2PW86G7wJess3ThuIuPXQja2vy1XyRtZ5Wd6sUPo0z6YQWRvtVO LCq+5XL/xL4Ju3YfTm2/TKELW69QsrlZW1EuuZQsZQh8sBI6U/atYpHCBNRMbh9B/R m7cuVK2RixBJw== Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org DMA mapped pages, including those pinned by mdev vendor drivers, might get unpinned and unmapped while migration is active and device is still running. For example, in pre-copy phase while guest driver could access those pages, host device or vendor driver can dirty these mapped pages. Such pages should be marked dirty so as to maintain memory consistency for a user making use of dirty page tracking. To get bitmap during unmap, user should allocate memory for bitmap, set it all zeros, set size of allocated memory, set page size to be considered for bitmap and set flag VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP. Signed-off-by: Kirti Wankhede Reviewed-by: Neo Jia --- drivers/vfio/vfio_iommu_type1.c | 68 +++++++++++++++++++++++++++++++++-------- include/uapi/linux/vfio.h | 10 ++++++ 2 files changed, 66 insertions(+), 12 deletions(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index bf740fef196f..b9ee78a615a4 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -195,11 +195,15 @@ static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old) static int vfio_dma_bitmap_alloc(struct vfio_dma *dma, size_t pgsize) { uint64_t npages = dma->size / pgsize; + size_t bitmap_size; if (npages > DIRTY_BITMAP_PAGES_MAX) return -EINVAL; - dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages), GFP_KERNEL); + /* Allocate extra 64 bits which are used for bitmap manipulation */ + bitmap_size = DIRTY_BITMAP_BYTES(npages) + sizeof(u64); + + dma->bitmap = kvzalloc(bitmap_size, GFP_KERNEL); if (!dma->bitmap) return -ENOMEM; @@ -1018,23 +1022,25 @@ static int verify_bitmap_size(uint64_t npages, uint64_t bitmap_size) } static int vfio_dma_do_unmap(struct vfio_iommu *iommu, - struct vfio_iommu_type1_dma_unmap *unmap) + struct vfio_iommu_type1_dma_unmap *unmap, + struct vfio_bitmap *bitmap) { - uint64_t mask; struct vfio_dma *dma, *dma_last = NULL; - size_t unmapped = 0; + size_t unmapped = 0, pgsize; int ret = 0, retries = 0; + unsigned long pgshift; mutex_lock(&iommu->lock); - mask = ((uint64_t)1 << __ffs(iommu->pgsize_bitmap)) - 1; + pgshift = __ffs(iommu->pgsize_bitmap); + pgsize = (size_t)1 << pgshift; - if (unmap->iova & mask) { + if (unmap->iova & (pgsize - 1)) { ret = -EINVAL; goto unlock; } - if (!unmap->size || unmap->size & mask) { + if (!unmap->size || unmap->size & (pgsize - 1)) { ret = -EINVAL; goto unlock; } @@ -1045,9 +1051,15 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, goto unlock; } - WARN_ON(mask & PAGE_MASK); -again: + /* When dirty tracking is enabled, allow only min supported pgsize */ + if ((unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) && + (!iommu->dirty_page_tracking || (bitmap->pgsize != pgsize))) { + ret = -EINVAL; + goto unlock; + } + WARN_ON((pgsize - 1) & PAGE_MASK); +again: /* * vfio-iommu-type1 (v1) - User mappings were coalesced together to * avoid tracking individual mappings. This means that the granularity @@ -1085,6 +1097,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, ret = -EINVAL; goto unlock; } + dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0); if (dma && dma->iova + dma->size != unmap->iova + unmap->size) { ret = -EINVAL; @@ -1128,6 +1141,14 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, mutex_lock(&iommu->lock); goto again; } + + if (unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) { + ret = update_user_bitmap(bitmap->data, dma, + unmap->iova, pgsize); + if (ret) + break; + } + unmapped += dma->size; vfio_remove_dma(iommu, dma); } @@ -2466,17 +2487,40 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, } else if (cmd == VFIO_IOMMU_UNMAP_DMA) { struct vfio_iommu_type1_dma_unmap unmap; - long ret; + struct vfio_bitmap bitmap = { 0 }; + int ret; minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size); if (copy_from_user(&unmap, (void __user *)arg, minsz)) return -EFAULT; - if (unmap.argsz < minsz || unmap.flags) + if (unmap.argsz < minsz || + unmap.flags & ~VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) return -EINVAL; - ret = vfio_dma_do_unmap(iommu, &unmap); + if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) { + unsigned long pgshift; + + if (unmap.argsz < (minsz + sizeof(bitmap))) + return -EINVAL; + + if (copy_from_user(&bitmap, + (void __user *)(arg + minsz), + sizeof(bitmap))) + return -EFAULT; + + if (!access_ok((void __user *)bitmap.data, bitmap.size)) + return -EINVAL; + + pgshift = __ffs(bitmap.pgsize); + ret = verify_bitmap_size(unmap.size >> pgshift, + bitmap.size); + if (ret) + return ret; + } + + ret = vfio_dma_do_unmap(iommu, &unmap, &bitmap); if (ret) return ret; diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 4850c1fef1f8..a1dd2150971e 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -1048,12 +1048,22 @@ struct vfio_bitmap { * field. No guarantee is made to the user that arbitrary unmaps of iova * or size different from those used in the original mapping call will * succeed. + * VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP should be set to get dirty bitmap + * before unmapping IO virtual addresses. When this flag is set, user must + * provide data[] as structure vfio_bitmap. User must allocate memory to get + * bitmap, zero the bitmap memory and must set size of allocated memory in + * vfio_bitmap.size field. A bit in bitmap represents one page of user provided + * page size in 'pgsize', consecutively starting from iova offset. Bit set + * indicates page at that offset from iova is dirty. Bitmap of pages in the + * range of unmapped size is returned in vfio_bitmap.data */ struct vfio_iommu_type1_dma_unmap { __u32 argsz; __u32 flags; +#define VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP (1 << 0) __u64 iova; /* IO virtual address */ __u64 size; /* Size of mapping (bytes) */ + __u8 data[]; }; #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14)