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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 3F68BC433E0 for ; Mon, 28 Dec 2020 09:12:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8A01D20799 for ; Mon, 28 Dec 2020 09:12:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A01D20799 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=bytedance.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8EA6D8D0008; Mon, 28 Dec 2020 04:12:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 873DD8D0003; Mon, 28 Dec 2020 04:12:57 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 713BB8D000A; Mon, 28 Dec 2020 04:12:57 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0206.hostedemail.com [216.40.44.206]) by kanga.kvack.org (Postfix) with ESMTP id 534068D0003 for ; Mon, 28 Dec 2020 04:12:57 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 0C61D8249980 for ; Mon, 28 Dec 2020 09:12:57 +0000 (UTC) X-FDA: 77642126394.20.shoe30_3c00aa527492 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id D40B0180BFBAD for ; Mon, 28 Dec 2020 09:12:56 +0000 (UTC) X-HE-Tag: shoe30_3c00aa527492 X-Filterd-Recvd-Size: 4805 Received: from mail-ej1-f48.google.com (mail-ej1-f48.google.com [209.85.218.48]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Mon, 28 Dec 2020 09:12:56 +0000 (UTC) Received: by mail-ej1-f48.google.com with SMTP id qw4so13321287ejb.12 for ; Mon, 28 Dec 2020 01:12:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=9lkawC7Fz3z0KmisaP79BxDG0EuYhifxKaeCSif+IJ8=; b=No5ZA7fdLz904gM1QjDqzfnM6H9sYP8u2SawxRpVGtan2jKKNJtXgRZsTlJKN/o0Ri 6IWBtNp/3MawVTr4wCOIDEl5RG6G6qzSWrLfd4SsMwBd195EiXXX5YoIWjiU46CVt7lv PwPrpo2/uR1dKKWYHG5/USG4zU64YwxfnB4H6p+EdmcIH1N0uXblRhB6o1R9E/tfgtA4 48ngDgyPYqw/ueOsoFH213WtJ9oJ6QKayfQZmHfkWlR7/dctxsc1vEUuPc+zKezqUXme C3NSsMVqZh/InqxzvmlyrOXOyu7/IKBDvtkj3KtFiMzOZqbH/ws5cedXoEZQjgcHSS1t zdqw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=9lkawC7Fz3z0KmisaP79BxDG0EuYhifxKaeCSif+IJ8=; b=SukNZRG1+W1HbmIHLQs7yq9v0KAc1Wjp7S7/jfbFYojhPtlt2kv9/9aiepDBiNGF/G KYxDlzVyCD7sJn5PLH7L8dFaseoyeqbljpOPSC+vF9bP3zjRgZYzqsxf305Sf1oegzGV y3eY8cmDrEaQK4ExEP9NKHwqem3J3BC7qApQ9Qz3NWaK9fFI5lcYPnEfZaNfPRmauqv2 dz4wEesXTy21zFw61AM9IV3Q90FNEbxWRm5IqvwjMGJWncZFKSRKx+cyugvhoaaXD73Q cMUwGtAunjH3FJQ4001qtQ+ggh2QtoO41z5gP/x7OLQLPDBybyrnjMHHjXduyRfbq5pi ztLQ== X-Gm-Message-State: AOAM530ScWuKUC+pcxRaMosCiys/0sxLEq/ivZfx72p53DItXeqh8gL4 XF2FFVP4RewMyogXgErvqxGuSQnaV01nTTSEf1D+ X-Google-Smtp-Source: ABdhPJwVbVkrlQalbTU6/h7VmiDK65ALhll1PK+HA8rICskwXreVpZDshXBbymnOf5bR1grgNYEKm9Zjmxa6xzgVyrk= X-Received: by 2002:a17:906:878d:: with SMTP id za13mr40480318ejb.395.1609146774881; Mon, 28 Dec 2020 01:12:54 -0800 (PST) MIME-Version: 1.0 References: <20201222145221.711-1-xieyongji@bytedance.com> <20201222145221.711-10-xieyongji@bytedance.com> <6818a214-d587-4f0b-7de6-13c4e7e94ab6@redhat.com> <595fe7d6-7876-26e4-0b7c-1d63ca6d7a97@redhat.com> <0e6faf9c-117a-e23c-8d6d-488d0ec37412@redhat.com> <2b24398c-e6d9-14ec-2c0d-c303d528e377@redhat.com> In-Reply-To: From: Yongji Xie Date: Mon, 28 Dec 2020 17:12:44 +0800 Message-ID: Subject: Re: Re: [RFC v2 09/13] vduse: Add support for processing vhost iotlb message To: Jason Wang Cc: "Michael S. Tsirkin" , Stefan Hajnoczi , sgarzare@redhat.com, Parav Pandit , akpm@linux-foundation.org, Randy Dunlap , Matthew Wilcox , viro@zeniv.linux.org.uk, axboe@kernel.dk, bcrl@kvack.org, corbet@lwn.net, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Dec 28, 2020 at 4:43 PM Jason Wang wrote: > > > On 2020/12/28 =E4=B8=8B=E5=8D=884:14, Yongji Xie wrote: > >> I see. So all the above two questions are because VHOST_IOTLB_INVALIDA= TE > >> is expected to be synchronous. This need to be solved by tweaking the > >> current VDUSE API or we can re-visit to go with descriptors relaying f= irst. > >> > > Actually all vdpa related operations are synchronous in current > > implementation. The ops.set_map/dma_map/dma_unmap should not return > > until the VDUSE_UPDATE_IOTLB/VDUSE_INVALIDATE_IOTLB message is replied > > by userspace. Could it solve this problem? > > > I was thinking whether or not we need to generate IOTLB_INVALIDATE > message to VDUSE during dma_unmap (vduse_dev_unmap_page). > > If we don't, we're probably fine. > It seems not feasible. This message will be also used in the virtio-vdpa case to notify userspace to unmap some pages during consistent dma unmapping. Maybe we can document it to make sure the users can handle the message correctly. Thanks, Yongji