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 DF7B1C433DF for ; Fri, 15 May 2020 15:33:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF91E20671 for ; Fri, 15 May 2020 15:33:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="SNYMq6nn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726293AbgEOPdN (ORCPT ); Fri, 15 May 2020 11:33:13 -0400 Received: from hqnvemgate26.nvidia.com ([216.228.121.65]:15816 "EHLO hqnvemgate26.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726183AbgEOPdN (ORCPT ); Fri, 15 May 2020 11:33:13 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 15 May 2020 08:33:00 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Fri, 15 May 2020 08:33:12 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Fri, 15 May 2020 08:33:12 -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 15:33:04 +0000 Subject: Re: [PATCH Kernel v20 5/8] vfio iommu: Implementation of ioctl for dirty pages tracking To: Alex Williamson CC: Yan Zhao , , , , , , , , , , , , , , , , , , , , References: <1589488667-9683-1-git-send-email-kwankhede@nvidia.com> <1589488667-9683-6-git-send-email-kwankhede@nvidia.com> <20200515100553.GA5559@joy-OptiPlex-7040> <20200515091533.53259392@w520.home> X-Nvconfidentiality: public From: Kirti Wankhede Message-ID: <8eb95e03-87f3-677a-698e-826ee0060deb@nvidia.com> Date: Fri, 15 May 2020 21:03:00 +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: <20200515091533.53259392@w520.home> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) 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=1589556780; bh=sBb4QJGBqFoY/7NqZIfplcyZOFjamlsLitNHDE9hqCw=; 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=SNYMq6nnW7P5oF33pNTInNAff7nLFrD5i7WWwd5UMohg+YYQ8AQ2eUcGwcXWUaoLJ VkgVvAVd+RcSSJ6lI/D2gU28UbEgBxf10zv/WiHDuyF0epnKUPd3Co5m7BaqQviON7 MkW2Y30G7sNm2ZzPYidxFkDme3KV4rXoQaFoJ5agLadTrEfah/1tphpti1jQbcyfOs UYd4b8YiV9+/caD0z/hsO7s5sWyx6bGTtwwLpDF1NFiq3em9/4FKYQFmmbzMxgrRFs rXoLEwByeN2A55/nqSwbLSMmWf/sKAbSUVYKKcjE/ueiK7HoTQSt1KFR0/GTJpGAcp JsE/eESOdLATg== Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 5/15/2020 8:45 PM, Alex Williamson wrote: > On Fri, 15 May 2020 16:44:38 +0530 > Kirti Wankhede wrote: > >> On 5/15/2020 3:35 PM, Yan Zhao wrote: >>> On Fri, May 15, 2020 at 02:07:44AM +0530, Kirti Wankhede wrote: >>>> 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 | 294 +++++++++++++++++++++++++++++++++++++++- >>>> 1 file changed, 288 insertions(+), 6 deletions(-) >>>> >>>> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c >>>> index de17787ffece..b76d3b14abfd 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 +191,74 @@ 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; >>>> + >>>> + dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages), 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 = rb_first(&iommu->dma_list); >>>> + >>>> + for (; 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 = rb_prev(n); >>>> + >>>> + for (; 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 = rb_first(&iommu->dma_list); >>>> + >>>> + for (; 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 +651,17 @@ 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, >>>> + (vpfn->iova - dma->iova) >> pgshift, 1); >>>> + } >>>> } >>>> >>>> ret = i; >>>> @@ -802,6 +896,7 @@ 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 +924,80 @@ 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; >>>> + >>>> + 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; >>>> + dma_addr_t i = iova, limit = iova + size; >>>> + unsigned long pgshift = __ffs(pgsize); >>>> + size_t sz = size; >>>> + int ret; >>>> + >>>> + while ((dma = vfio_find_dma(iommu, i, sz))) { >>> not quite get the logic here. >>> if (i, i + size) is intersecting with (dma->iova, dma->iova + dma->size), >>> and a dma is found here, why the whole bitmap is cleared and copied? >>> >> >> This works with multiple but full vfio_dma, not intersects of vfio_dma, >> similar to unmap ioctl. > > I don't see that the VFIO_IOMMU_DIRTY_PAGES ioctl validates that like > VFIO_IOMMU_UNMAP_DMA does though. We should have the same test as > vfio_dma_do_unmap() to verify that they user range doesn't bisect a > mapping, otherwise Yan is right, it looks like we allow the user to > specify an arbitrary range that might bisect a bitmap, but we clear and > attempt to copy the entire bitmap to the user buffer regardless. Sure, updating patch. I'll send next version in some time. Thanks, Kirti 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,URIBL_BLOCKED,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 963DDC433DF for ; Fri, 15 May 2020 15:34:01 +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 6405820758 for ; Fri, 15 May 2020 15:34:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="SNYMq6nn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6405820758 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:38714 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jZcLY-0002NP-K8 for qemu-devel@archiver.kernel.org; Fri, 15 May 2020 11:34:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53674) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jZcKq-0001lS-AB for qemu-devel@nongnu.org; Fri, 15 May 2020 11:33:16 -0400 Received: from hqnvemgate26.nvidia.com ([216.228.121.65]:15822) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jZcKo-00010L-Nh for qemu-devel@nongnu.org; Fri, 15 May 2020 11:33:15 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 15 May 2020 08:33:00 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Fri, 15 May 2020 08:33:12 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Fri, 15 May 2020 08:33:12 -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 15:33:04 +0000 Subject: Re: [PATCH Kernel v20 5/8] vfio iommu: Implementation of ioctl for dirty pages tracking To: Alex Williamson References: <1589488667-9683-1-git-send-email-kwankhede@nvidia.com> <1589488667-9683-6-git-send-email-kwankhede@nvidia.com> <20200515100553.GA5559@joy-OptiPlex-7040> <20200515091533.53259392@w520.home> X-Nvconfidentiality: public From: Kirti Wankhede Message-ID: <8eb95e03-87f3-677a-698e-826ee0060deb@nvidia.com> Date: Fri, 15 May 2020 21:03:00 +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: <20200515091533.53259392@w520.home> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) 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=1589556780; bh=sBb4QJGBqFoY/7NqZIfplcyZOFjamlsLitNHDE9hqCw=; 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=SNYMq6nnW7P5oF33pNTInNAff7nLFrD5i7WWwd5UMohg+YYQ8AQ2eUcGwcXWUaoLJ VkgVvAVd+RcSSJ6lI/D2gU28UbEgBxf10zv/WiHDuyF0epnKUPd3Co5m7BaqQviON7 MkW2Y30G7sNm2ZzPYidxFkDme3KV4rXoQaFoJ5agLadTrEfah/1tphpti1jQbcyfOs UYd4b8YiV9+/caD0z/hsO7s5sWyx6bGTtwwLpDF1NFiq3em9/4FKYQFmmbzMxgrRFs rXoLEwByeN2A55/nqSwbLSMmWf/sKAbSUVYKKcjE/ueiK7HoTQSt1KFR0/GTJpGAcp JsE/eESOdLATg== Received-SPF: pass client-ip=216.228.121.65; envelope-from=kwankhede@nvidia.com; helo=hqnvemgate26.nvidia.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/15 11:33:13 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 Zhao , 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 8:45 PM, Alex Williamson wrote: > On Fri, 15 May 2020 16:44:38 +0530 > Kirti Wankhede wrote: > >> On 5/15/2020 3:35 PM, Yan Zhao wrote: >>> On Fri, May 15, 2020 at 02:07:44AM +0530, Kirti Wankhede wrote: >>>> 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 | 294 +++++++++++++++++++++++++++++++++++++++- >>>> 1 file changed, 288 insertions(+), 6 deletions(-) >>>> >>>> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c >>>> index de17787ffece..b76d3b14abfd 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 +191,74 @@ 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; >>>> + >>>> + dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages), 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 = rb_first(&iommu->dma_list); >>>> + >>>> + for (; 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 = rb_prev(n); >>>> + >>>> + for (; 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 = rb_first(&iommu->dma_list); >>>> + >>>> + for (; 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 +651,17 @@ 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, >>>> + (vpfn->iova - dma->iova) >> pgshift, 1); >>>> + } >>>> } >>>> >>>> ret = i; >>>> @@ -802,6 +896,7 @@ 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 +924,80 @@ 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; >>>> + >>>> + 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; >>>> + dma_addr_t i = iova, limit = iova + size; >>>> + unsigned long pgshift = __ffs(pgsize); >>>> + size_t sz = size; >>>> + int ret; >>>> + >>>> + while ((dma = vfio_find_dma(iommu, i, sz))) { >>> not quite get the logic here. >>> if (i, i + size) is intersecting with (dma->iova, dma->iova + dma->size), >>> and a dma is found here, why the whole bitmap is cleared and copied? >>> >> >> This works with multiple but full vfio_dma, not intersects of vfio_dma, >> similar to unmap ioctl. > > I don't see that the VFIO_IOMMU_DIRTY_PAGES ioctl validates that like > VFIO_IOMMU_UNMAP_DMA does though. We should have the same test as > vfio_dma_do_unmap() to verify that they user range doesn't bisect a > mapping, otherwise Yan is right, it looks like we allow the user to > specify an arbitrary range that might bisect a bitmap, but we clear and > attempt to copy the entire bitmap to the user buffer regardless. Sure, updating patch. I'll send next version in some time. Thanks, Kirti