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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 45C1EC433E9 for ; Mon, 11 Jan 2021 21:51:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 070A922D03 for ; Mon, 11 Jan 2021 21:51:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733272AbhAKVuu (ORCPT ); Mon, 11 Jan 2021 16:50:50 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:39610 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732824AbhAKVut (ORCPT ); Mon, 11 Jan 2021 16:50:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610401763; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YcHYs6OZqBWCMgb0rpCE3M6MXEuKUj2tsDDbqZh/79Q=; b=Hz2Y9oRlLLtMr3VK3hFnKgSjz/XHyxWZA316H6F4lON/5wdpYqWK+8ONUkDjxlnW0XTpjN wHflJdjBnNUr9NIoDmyp72csv5bhcRuMBP+xRfBPB5mc2pdrXSEugpmhNfTu9hiJu6jYg1 qt2lzO7fsEFjgsevSv35ObPgMaYYJ6g= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-70-ekx4pMUpPXWmh16-SihWQQ-1; Mon, 11 Jan 2021 16:49:19 -0500 X-MC-Unique: ekx4pMUpPXWmh16-SihWQQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8B8F1107ACF7; Mon, 11 Jan 2021 21:49:16 +0000 (UTC) Received: from omen.home.shazbot.org (ovpn-112-255.phx2.redhat.com [10.3.112.255]) by smtp.corp.redhat.com (Postfix) with ESMTP id 828CE60BE2; Mon, 11 Jan 2021 21:49:14 +0000 (UTC) Date: Mon, 11 Jan 2021 14:49:13 -0700 From: Alex Williamson To: Keqian Zhu Cc: , , , , , Kirti Wankhede , Cornelia Huck , Will Deacon , Marc Zyngier , Catalin Marinas , Mark Rutland , James Morse , Robin Murphy , Joerg Roedel , "Daniel Lezcano" , Thomas Gleixner , Suzuki K Poulose , Julien Thierry , Andrew Morton , Alexios Zavras , , Subject: Re: [PATCH 4/5] vfio/iommu_type1: Carefully use unmap_unpin_all during dirty tracking Message-ID: <20210111144913.3092b1b1@omen.home.shazbot.org> In-Reply-To: <20210107092901.19712-5-zhukeqian1@huawei.com> References: <20210107092901.19712-1-zhukeqian1@huawei.com> <20210107092901.19712-5-zhukeqian1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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 > 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);