From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1F12C433E0 for ; Fri, 15 May 2020 04:16:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C18AE20760 for ; Fri, 15 May 2020 04:16:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="ISXGpDUN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726219AbgEOEQ5 (ORCPT ); Fri, 15 May 2020 00:16:57 -0400 Received: from hqnvemgate25.nvidia.com ([216.228.121.64]:10526 "EHLO hqnvemgate25.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725616AbgEOEQ5 (ORCPT ); Fri, 15 May 2020 00:16:57 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Thu, 14 May 2020 21:15:41 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Thu, 14 May 2020 21:16:56 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Thu, 14 May 2020 21:16:56 -0700 Received: from [10.40.103.94] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 15 May 2020 04:16:48 +0000 Subject: Re: [PATCH Kernel v20 6/8] vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before unmap To: Alex Williamson CC: , , , , , , , , , , , , , , , , , , , , References: <1589488667-9683-1-git-send-email-kwankhede@nvidia.com> <1589488667-9683-7-git-send-email-kwankhede@nvidia.com> <20200514212706.036a336a@x1.home> X-Nvconfidentiality: public From: Kirti Wankhede Message-ID: <5256f488-2d11-eb0f-6980-eea23f4d3019@nvidia.com> Date: Fri, 15 May 2020 09:46:43 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200514212706.036a336a@x1.home> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL105.nvidia.com (172.20.187.12) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1589516141; bh=XMg/MUjSJ8ufYGAEL5KNMZd52Q+a1k4OHYEBEthF88E=; h=X-PGP-Universal:Subject:To:CC:References:X-Nvconfidentiality:From: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=ISXGpDUNxuuk3xwoFU5YNMtKKOVuLAbT7bv6Wy7n4gEn5awispTei6jfPuoO/HNfF 1AwuzmiyhEuuKnyxwc602MzE7cznO7CZnBLkc2H2qaBJuviwjhmN1JQv7LBjG+uZNe 74OFBuZaUEFC0Grtj3PcYbb53I0cfZrJx4B7ugIKuK4xaab2dWUE+iMVpHhdUEtPuC VrxrVyjn7at4htPMXE7+ocyODbIfecnj2AbxK/LIoKZ6/dX+cULFTG2HW88n5nxIVg vFss9Idcwa8RZ2Y/mmyA7VACB6Pz6GLdltojzAoCk1hsvvfFPAoZJNDyUB4VTdU1lU qC0sTNyyTqHhg== Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 5/15/2020 8:57 AM, Alex Williamson wrote: > On Fri, 15 May 2020 02:07:45 +0530 > Kirti Wankhede wrote: > >> 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 | 77 ++++++++++++++++++++++++++++++++++------- >> include/uapi/linux/vfio.h | 10 ++++++ >> 2 files changed, 75 insertions(+), 12 deletions(-) >> >> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c >> index b76d3b14abfd..a1dc57bcece5 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; >> >> @@ -999,23 +1003,25 @@ 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; >> } >> @@ -1026,9 +1032,15 @@ 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 >> @@ -1066,6 +1078,7 @@ 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; >> @@ -1083,6 +1096,23 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, >> if (dma->task->mm != current->mm) >> break; >> >> + if ((unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) && >> + (dma_last != dma)) { >> + >> + /* >> + * mark all pages dirty if all pages are pinned and >> + * mapped >> + */ >> + if (dma->iommu_mapped) >> + bitmap_set(dma->bitmap, 0, >> + dma->size >> pgshift); > > Nit, all the callers of update_user_bitmap() precede the call with this > identical operation, we should probably push it into the function to do > it. > >> + >> + ret = update_user_bitmap(bitmap->data, dma, >> + unmap->iova, pgsize); >> + if (ret) >> + break; >> + } >> + > > As noted last time, the above is just busy work if pfn_list is not > already empty. The entire code block above should be moved to after > the block below. Thanks, > pfn_list will be empty for IOMMU backed devices where all pages are pinned and mapped, but those should be reported as dirty. So moved it back above empty pfn_list check. Thanks, Kirti > Alex > >> if (!RB_EMPTY_ROOT(&dma->pfn_list)) { >> struct vfio_iommu_type1_dma_unmap nb_unmap; >> >> @@ -2447,17 +2477,40 @@ 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 123de3bc2dce..0a0c7315ddd6 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) > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AEFBEC433E0 for ; Fri, 15 May 2020 04:17:49 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7113E206F1 for ; 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Fri, 15 May 2020 00:16:59 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Thu, 14 May 2020 21:15:41 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Thu, 14 May 2020 21:16:56 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Thu, 14 May 2020 21:16:56 -0700 Received: from [10.40.103.94] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 15 May 2020 04:16:48 +0000 Subject: Re: [PATCH Kernel v20 6/8] vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before unmap To: Alex Williamson References: <1589488667-9683-1-git-send-email-kwankhede@nvidia.com> <1589488667-9683-7-git-send-email-kwankhede@nvidia.com> <20200514212706.036a336a@x1.home> X-Nvconfidentiality: public From: Kirti Wankhede Message-ID: <5256f488-2d11-eb0f-6980-eea23f4d3019@nvidia.com> Date: Fri, 15 May 2020 09:46:43 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; 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envelope-from=kwankhede@nvidia.com; helo=hqnvemgate25.nvidia.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/15 00:16:57 X-ACL-Warn: Detected OS = Windows 7 or 8 [fuzzy] X-Spam_score_int: -70 X-Spam_score: -7.1 X-Spam_bar: ------- X-Spam_report: (-7.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_HI=-5, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Zhengxiao.zx@Alibaba-inc.com, kevin.tian@intel.com, yi.l.liu@intel.com, cjia@nvidia.com, kvm@vger.kernel.org, eskultet@redhat.com, ziye.yang@intel.com, qemu-devel@nongnu.org, cohuck@redhat.com, shuangtai.tst@alibaba-inc.com, dgilbert@redhat.com, zhi.a.wang@intel.com, mlevitsk@redhat.com, pasic@linux.ibm.com, aik@ozlabs.ru, eauger@redhat.com, felipe@nutanix.com, jonathan.davies@nutanix.com, yan.y.zhao@intel.com, changpeng.liu@intel.com, Ken.Xue@amd.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/15/2020 8:57 AM, Alex Williamson wrote: > On Fri, 15 May 2020 02:07:45 +0530 > Kirti Wankhede wrote: > >> 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 | 77 ++++++++++++++++++++++++++++++++++------- >> include/uapi/linux/vfio.h | 10 ++++++ >> 2 files changed, 75 insertions(+), 12 deletions(-) >> >> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c >> index b76d3b14abfd..a1dc57bcece5 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; >> >> @@ -999,23 +1003,25 @@ 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; >> } >> @@ -1026,9 +1032,15 @@ 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 >> @@ -1066,6 +1078,7 @@ 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; >> @@ -1083,6 +1096,23 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, >> if (dma->task->mm != current->mm) >> break; >> >> + if ((unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) && >> + (dma_last != dma)) { >> + >> + /* >> + * mark all pages dirty if all pages are pinned and >> + * mapped >> + */ >> + if (dma->iommu_mapped) >> + bitmap_set(dma->bitmap, 0, >> + dma->size >> pgshift); > > Nit, all the callers of update_user_bitmap() precede the call with this > identical operation, we should probably push it into the function to do > it. > >> + >> + ret = update_user_bitmap(bitmap->data, dma, >> + unmap->iova, pgsize); >> + if (ret) >> + break; >> + } >> + > > As noted last time, the above is just busy work if pfn_list is not > already empty. The entire code block above should be moved to after > the block below. Thanks, > pfn_list will be empty for IOMMU backed devices where all pages are pinned and mapped, but those should be reported as dirty. So moved it back above empty pfn_list check. Thanks, Kirti > Alex > >> if (!RB_EMPTY_ROOT(&dma->pfn_list)) { >> struct vfio_iommu_type1_dma_unmap nb_unmap; >> >> @@ -2447,17 +2477,40 @@ 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 123de3bc2dce..0a0c7315ddd6 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) >