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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 0C35DC433E6 for ; Tue, 12 Jan 2021 12:05:01 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 63EA022D2C for ; Tue, 12 Jan 2021 12:05:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 63EA022D2C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id E688984480; Tue, 12 Jan 2021 12:04:59 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id a1mo_XWpYuew; Tue, 12 Jan 2021 12:04:56 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by fraxinus.osuosl.org (Postfix) with ESMTP id 6A9B3860BE; Tue, 12 Jan 2021 12:04:56 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 22CE0C0893; Tue, 12 Jan 2021 12:04:56 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 406DDC013A for ; Tue, 12 Jan 2021 12:04:54 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 2782D860FC for ; Tue, 12 Jan 2021 12:04:54 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id XSn6c5Vr7ALQ for ; Tue, 12 Jan 2021 12:04:52 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 0B87A860BE for ; Tue, 12 Jan 2021 12:04:52 +0000 (UTC) Received: from DGGEMS410-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DFTkD0LGDzl46q; Tue, 12 Jan 2021 20:03:32 +0800 (CST) Received: from [10.174.184.42] (10.174.184.42) by DGGEMS410-HUB.china.huawei.com (10.3.19.210) with Microsoft SMTP Server id 14.3.498.0; Tue, 12 Jan 2021 20:04:39 +0800 Subject: Re: [PATCH 4/5] vfio/iommu_type1: Carefully use unmap_unpin_all during dirty tracking To: Alex Williamson References: <20210107092901.19712-1-zhukeqian1@huawei.com> <20210107092901.19712-5-zhukeqian1@huawei.com> <20210111144913.3092b1b1@omen.home.shazbot.org> From: Keqian Zhu Message-ID: <198f0afd-343a-9fbc-9556-95670ca76a2c@huawei.com> Date: Tue, 12 Jan 2021 20:04:38 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <20210111144913.3092b1b1@omen.home.shazbot.org> X-Originating-IP: [10.174.184.42] X-CFilter-Loop: Reflected Cc: Mark Rutland , jiangkunkun@huawei.com, kvm@vger.kernel.org, Catalin Marinas , Kirti Wankhede , Will Deacon , kvmarm@lists.cs.columbia.edu, Marc Zyngier , Daniel Lezcano , wanghaibin.wang@huawei.com, Julien Thierry , Suzuki K Poulose , Alexios Zavras , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Cornelia Huck , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, James Morse , Andrew Morton , Robin Murphy X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 2021/1/12 5:49, Alex Williamson wrote: > On Thu, 7 Jan 2021 17:29:00 +0800 > Keqian Zhu wrote: > >> If we detach group during dirty page tracking, we shouldn't remove >> vfio_dma, because dirty log will lose. >> >> But we don't prevent unmap_unpin_all in vfio_iommu_release, because >> under normal procedure, dirty tracking has been stopped. > > This looks like it's creating a larger problem than it's fixing, it's > not our job to maintain the dirty bitmap regardless of what the user > does. If the user detaches the last group in a container causing the > mappings within that container to be deconstructed before the user has > collected dirty pages, that sounds like a user error. A container with > no groups is de-privileged and therefore loses all state. Thanks, > > Alex Hi Alex, This looks good to me ;-). That's a reasonable constraint for user behavior. What about replacing this patch with an addition to the uapi document of VFIO_GROUP_UNSET_CONTAINER? User should pay attention to this when call this ioctl during dirty tracking. And any comments on other patches? thanks. Thanks. Keqian > >> Fixes: d6a4c185660c ("vfio iommu: Implementation of ioctl for dirty pages tracking") >> Signed-off-by: Keqian Zhu >> --- >> drivers/vfio/vfio_iommu_type1.c | 14 ++++++++++++-- >> 1 file changed, 12 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c >> index 26b7eb2a5cfc..9776a059904d 100644 >> --- a/drivers/vfio/vfio_iommu_type1.c >> +++ b/drivers/vfio/vfio_iommu_type1.c >> @@ -2373,7 +2373,12 @@ static void vfio_iommu_type1_detach_group(void *iommu_data, >> if (list_empty(&iommu->external_domain->group_list)) { >> vfio_sanity_check_pfn_list(iommu); >> >> - if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) >> + /* >> + * During dirty page tracking, we can't remove >> + * vfio_dma because dirty log will lose. >> + */ >> + if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) && >> + !iommu->dirty_page_tracking) >> vfio_iommu_unmap_unpin_all(iommu); >> >> kfree(iommu->external_domain); >> @@ -2406,10 +2411,15 @@ static void vfio_iommu_type1_detach_group(void *iommu_data, >> * iommu and external domain doesn't exist, then all the >> * mappings go away too. If it's the last domain with iommu and >> * external domain exist, update accounting >> + * >> + * Note: During dirty page tracking, we can't remove vfio_dma >> + * because dirty log will lose. Just update accounting is a good >> + * choice. >> */ >> if (list_empty(&domain->group_list)) { >> if (list_is_singular(&iommu->domain_list)) { >> - if (!iommu->external_domain) >> + if (!iommu->external_domain && >> + !iommu->dirty_page_tracking) >> vfio_iommu_unmap_unpin_all(iommu); >> else >> vfio_iommu_unmap_unpin_reaccount(iommu); > > . > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu