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=-8.5 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 2D179C43331 for ; Tue, 31 Mar 2020 18:46:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EED92208E0 for ; Tue, 31 Mar 2020 18:46:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="GAe7CXCc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727708AbgCaSq2 (ORCPT ); Tue, 31 Mar 2020 14:46:28 -0400 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:8046 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726209AbgCaSq1 (ORCPT ); Tue, 31 Mar 2020 14:46:27 -0400 Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 31 Mar 2020 11:44:50 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Tue, 31 Mar 2020 11:46:27 -0700 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Tue, 31 Mar 2020 11:46:27 -0700 Received: from [10.40.162.111] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 31 Mar 2020 18:46:18 +0000 Subject: Re: [PATCH v17 Kernel 5/7] vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before unmap To: Alex Williamson CC: , , , , , , , , , , , , , , , , , , , , References: <1585587044-2408-1-git-send-email-kwankhede@nvidia.com> <1585587044-2408-6-git-send-email-kwankhede@nvidia.com> <20200330153421.6246c2c6@w520.home> X-Nvconfidentiality: public From: Kirti Wankhede Message-ID: <66af06b5-4e87-9f7a-be85-08a68d6ab982@nvidia.com> Date: Wed, 1 Apr 2020 00:16:13 +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: <20200330153421.6246c2c6@w520.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=1585680290; bh=iWzduZHbPfAp/fpaS0jcEjAbJwVc7RSEbxv51ssxb+4=; 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=GAe7CXCcFLpbdEe0Z6rQS9Aw3uM2cOnGPiTMJuU9K4g8ym+NSf/4D3/Knjzaah3qI Mbff020O6MmoXnpMhBzgjIYWbJm7uX61roLebl5dXcYkIoahYJD+wgPtY2K2iFTTOI PLAls7X/ja/eatyNTXqMKEQ61EyK6IuK4zTucztDvAfFYiXrorx/eNff+KKsO1KnVy d2z+77/dbdOzlxLxiNEgpFvSVUcsXPur2M3/c+8c+450+2bSL8atpkTfXHI1l8oJro toOFZ6J2YzftnHLrGw7pyZfnHqH6UnhtkT+5kvaFFnytoCx3BpmncQz2nWbEklpq8g OIxLNqGRUVJPA== Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 3/31/2020 3:04 AM, Alex Williamson wrote: > On Mon, 30 Mar 2020 22:20:42 +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 >> 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 | 55 ++++++++++++++++++++++++++++++++++++++--- >> include/uapi/linux/vfio.h | 10 ++++++++ >> 2 files changed, 61 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c >> index 5efebc2b60e1..266550bd7307 100644 >> --- a/drivers/vfio/vfio_iommu_type1.c >> +++ b/drivers/vfio/vfio_iommu_type1.c >> @@ -983,7 +983,8 @@ 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; >> @@ -1034,6 +1035,10 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, >> * will be returned if these conditions are not met. The v2 interface >> * will only return success and a size of zero if there were no >> * mappings within the range. >> + * >> + * When VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP flag is set, unmap request >> + * must be for single mapping. Multiple mappings with this flag set is >> + * not supported. >> */ >> if (iommu->v2) { >> dma = vfio_find_dma(iommu, unmap->iova, 1); >> @@ -1041,6 +1046,14 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, >> ret = -EINVAL; >> goto unlock; >> } >> + >> + if ((unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) && >> + dma && >> + (dma->iova != unmap->iova || dma->size != unmap->size)) { > > > I think your intention was to return error if the user asked for the > dirty bitmap and the requested unmap range doesn't exactly match the > vfio_dma. Not finding a vfio_dma should therefore also be an error. > For example, if we had a single mapping at {0x1000-0x1fff} and the user > unmapped with dirty bitmap {0x0-0x2fff}, that should return an error, > but it's not caught by the above because there is no vfio_dma @0x0. > Therefore I think you want: > > ((unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) && > (!dma || dma->iova != unmap->iova || dma->size != unmap->size)) > > Right? Thanks, > Yes, updating check. Is !dma here also error case when VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP flag is not set? DMA_UNMAP ioctl returns how much was unmapped, from user space perspective this would be from start of range (unmap->iova), right? Thanks, Kirti