From patchwork Thu Mar 25 11:12:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Grall X-Patchwork-Id: 12163703 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 8E1C6C433C1 for ; Thu, 25 Mar 2021 11:13:23 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 3A66461A25 for ; Thu, 25 Mar 2021 11:13:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A66461A25 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.101376.193857 (Exim 4.92) (envelope-from ) id 1lPNvO-0003vg-KP; Thu, 25 Mar 2021 11:13:14 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 101376.193857; Thu, 25 Mar 2021 11:13:14 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lPNvO-0003vZ-HF; Thu, 25 Mar 2021 11:13:14 +0000 Received: by outflank-mailman (input) for mailman id 101376; Thu, 25 Mar 2021 11:13:12 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lPNvM-0003vL-OL for xen-devel@lists.xenproject.org; Thu, 25 Mar 2021 11:13:12 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lPNvL-0002Mn-CZ; Thu, 25 Mar 2021 11:13:11 +0000 Received: from 54-240-197-235.amazon.com ([54.240.197.235] helo=ufe34d9ed68d054.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lPNvL-0002fE-0C; Thu, 25 Mar 2021 11:13:11 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Message-Id:Date:Subject:Cc:To:From; bh=aOQI9Mr0Yo2TD1tNatsazTuCAXLpcS3ebRcXECoMhhw=; b=QG5KoAnmaAdnEe3OVNDsQPEB4g rEKBuSu/My5VuL6dh8yDf5xTv0L4Ghp0dyk4nvUHuKPHWWIOY5NW3Ud0L5m9hCp1/e4tVVtYaGG5b 3O0X/YuM25ucfX993UFIV9PvD3MUmohDmRuxwdlZkZRqC1QS9wd9z0Y9TKpm9CthZo8I=; From: Julien Grall To: xen-devel@lists.xenproject.org Cc: julien@xen.org, Julien Grall , Andrew Cooper , George Dunlap , Ian Jackson , Jan Beulich , Stefano Stabellini , Wei Liu , raphning@gmail.com, edvin.torok@citrix.com, jgross@suse.com Subject: [PATCH for-4.15?] docs/design: Update xenstore-migration.md Date: Thu, 25 Mar 2021 11:12:55 +0000 Message-Id: <20210325111255.16330-1-julien@xen.org> X-Mailer: git-send-email 2.17.1 From: Julien Grall It is not very clear the shared page adddress is not contained in the connection record. Additionally, it is misleading to say the grant will always point to the share paged as a domain is free to revoke the permission. The restore code would need to make sure it doesn't fail/crash if this is happening. The sentence is now replaced with a paragraph explaining why the GFN is not preserved and that the grant is not guarantee to exist during restore. Take the opportunity to replace "code" with "node" when description the permission. Reported-by: Raphael Ning Signed-off-by: Julien Grall Reviewed-by: Juergen Gross --- Cc: raphning@gmail.com Cc: edvin.torok@citrix.com Cc: jgross@suse.com Ian, would you still consider documentation update for 4.15? --- docs/designs/xenstore-migration.md | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/docs/designs/xenstore-migration.md b/docs/designs/xenstore-migration.md index 1a5b94b31da8..5f1155273ec3 100644 --- a/docs/designs/xenstore-migration.md +++ b/docs/designs/xenstore-migration.md @@ -216,8 +216,10 @@ For `shared ring` connections it is as follows: | | by xenstored to communicate with `domid` | | | | -Since the ABI guarantees that entry 1 in `domid`'s grant table will always -contain the GFN of the shared page. +The GFN of the shared page is not preserved because the ABI reserves +entry 1 in `domid`'s grant table to point to the xenstore shared page. +Note there is no guarantee the page will still be valid at the time of +the restore because a domain can revoke the permission. For `socket` connections it is as follows: @@ -398,7 +400,7 @@ A node permission specifier has the following format: | | | | `domid` | The domain-id to which the permission relates | -Note that perm1 defines the domain owning the code. See [4] for more +Note that perm1 defines the domain owning the node. See [4] for more explanation of node permissions. * * *