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=-15.5 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 C5F3BC433DB for ; Tue, 5 Jan 2021 12:59:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 953B922AAC for ; Tue, 5 Jan 2021 12:59:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725939AbhAEM6t (ORCPT ); Tue, 5 Jan 2021 07:58:49 -0500 Received: from mail-wm1-f41.google.com ([209.85.128.41]:51263 "EHLO mail-wm1-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725776AbhAEM6s (ORCPT ); Tue, 5 Jan 2021 07:58:48 -0500 Received: by mail-wm1-f41.google.com with SMTP id v14so2948403wml.1; Tue, 05 Jan 2021 04:58:32 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=836qpMt3CNg5/h01x1jVl4EStobkNHavjjRKKOo1oHA=; b=r0o4qq85L/DX7NMT8jxm2sq+LfX3Dv7G5vsiTNtw5ggVpH+u/RE1vicqZLYtZw8znP w1oQx+87He8pIFbtigQLjDDpdctiy79JOkCYH1EQ1xzUq/uZOHMefQWZ+SNz2fSukkrZ NFnJXSWrcH4ILzz4u29t7qfIDi/XM43KEP0pxO3kvMS5M3wX7xGwM/V+5HovKXwTyj0t klE7jv1wTM2j+8HLisO/geCNJ2AWeOeBrSClfpT1mbmMJSMi6uMNEOfqLtjo3MrBToGV k6e2FgR8/4RIZuqajhl5WA4YsU3W8BdQ2BQCG394chRbAsFY5WsLW05Bget3wavXgtQ5 B1wg== X-Gm-Message-State: AOAM532Wcaz8ljdnn9sXm+XT8t8DPOioTnPSQDPE8k5xfE9kCYhyVBtZ JWgeik6wRtBXIR9zaVNNEC6nVL3nOwY= X-Google-Smtp-Source: ABdhPJw07hcLlLDflKTEHckRCl8TiLu4ghZ+pqyA8N4DfcJlex2g/C6uTXWl5XeAB0DQ84TxH5R2Ew== X-Received: by 2002:a1c:770d:: with SMTP id t13mr3517461wmi.153.1609851486993; Tue, 05 Jan 2021 04:58:06 -0800 (PST) Received: from liuwe-devbox-debian-v2 ([51.145.34.42]) by smtp.gmail.com with ESMTPSA id b14sm93556485wrx.77.2021.01.05.04.58.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 04:58:06 -0800 (PST) Date: Tue, 5 Jan 2021 12:58:05 +0000 From: Wei Liu To: Dexuan Cui Cc: wei.liu@kernel.org, kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, mikelley@microsoft.com, vkuznets@redhat.com, marcelo.cerri@canonical.com Subject: Re: [PATCH] Drivers: hv: vmbus: Add /sys/bus/vmbus/supported_features Message-ID: <20210105125805.7yypaghcpgafsrcs@liuwe-devbox-debian-v2> References: <20201223001222.30242-1-decui@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201223001222.30242-1-decui@microsoft.com> User-Agent: NeoMutt/20180716 Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Tue, Dec 22, 2020 at 04:12:22PM -0800, Dexuan Cui wrote: > When a Linux VM runs on Hyper-V, if the host toolstack doesn't support > hibernation for the VM (this happens on old Hyper-V hosts like Windows > Server 2016, or new Hyper-V hosts if the admin or user doesn't declare > the hibernation intent for the VM), the VM is discouraged from trying > hibernation (because the host doesn't guarantee that the VM's virtual > hardware configuration will remain exactly the same across hibernation), > i.e. the VM should not try to set up the swap partition/file for > hibernation, etc. > > x86 Hyper-V uses the presence of the virtual ACPI S4 state as the > indication of the host toolstack support for a VM. Currently there is > no easy and reliable way for the userspace to detect the presence of > the state (see https://lkml.org/lkml/2020/12/11/1097). Add > /sys/bus/vmbus/supported_features for this purpose. > > Signed-off-by: Dexuan Cui > --- > Documentation/ABI/stable/sysfs-bus-vmbus | 7 +++++++ > drivers/hv/vmbus_drv.c | 20 ++++++++++++++++++++ > 2 files changed, 27 insertions(+) > > diff --git a/Documentation/ABI/stable/sysfs-bus-vmbus b/Documentation/ABI/stable/sysfs-bus-vmbus > index c27b7b89477c..3ba765ae6695 100644 > --- a/Documentation/ABI/stable/sysfs-bus-vmbus > +++ b/Documentation/ABI/stable/sysfs-bus-vmbus > @@ -1,3 +1,10 @@ > +What: /sys/bus/vmbus/supported_features > +Date: Dec 2020 > +KernelVersion: 5.11 Too late for 5.11 now. Given this is a list of strings, do you want to enumerate them in a Values section or the Description section? Wei.