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=-10.5 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 CC80CC433E0 for ; Mon, 11 Jan 2021 11:06:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F68C22482 for ; Mon, 11 Jan 2021 11:06:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728477AbhAKLGl (ORCPT ); Mon, 11 Jan 2021 06:06:41 -0500 Received: from mail-wm1-f42.google.com ([209.85.128.42]:36506 "EHLO mail-wm1-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728251AbhAKLGl (ORCPT ); Mon, 11 Jan 2021 06:06:41 -0500 Received: by mail-wm1-f42.google.com with SMTP id y23so14644687wmi.1; Mon, 11 Jan 2021 03:06:25 -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=tpCjrqa5CVCjTtdyszt7E01t6dI8BxCUY3VyFYIKnzc=; b=E14cCJGAKR0VVAf/nueRrqofxn8HM4EXDvXIpdwyeiBTqZhLO/hdfy6SOWrPtc8sci 6lNM5fTfnZh/GsslwsyJEb+KNP1I7XHG9s5aflsS6D80ZFE96rdjVpaFkj95lkk93IpN WCnbdaqd6WhwDjw/TjaxUWEjr0SIf9xjPshlesJOKSTj1/evwdsg3rIakYd1arAhPO7E tMkhk+K2P71D+vyFe6htbamw86H8ZDNUWqaLdgSAwogggETVydSNbSRVyZV0LAJfcDbY vNTtFPiFABjntDd7ceplRWS/cMvGOpGCzUvDpwbiybjwDL9VOVoW5TUz9lj7+GbCfvMN EyBA== X-Gm-Message-State: AOAM533lPpsAKq1ACMNx5cWYW6Z9uZSnFE9qSqCIfABEmbnlOV6u4e7o O9EncJX2jE4iSlnbifXljOY= X-Google-Smtp-Source: ABdhPJwi2PYZZHP8Chl2DszucgzD2i5NNS1Hc4Mm5HeX+ZGszieBgyupe4bqqXE+jBb6zFAyc+iyYg== X-Received: by 2002:a1c:3206:: with SMTP id y6mr84330wmy.127.1610363159783; Mon, 11 Jan 2021 03:05:59 -0800 (PST) Received: from liuwe-devbox-debian-v2 ([51.145.34.42]) by smtp.gmail.com with ESMTPSA id s133sm21303578wmf.38.2021.01.11.03.05.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Jan 2021 03:05:59 -0800 (PST) Date: Mon, 11 Jan 2021 11:05:57 +0000 From: Wei Liu To: Michael Kelley Cc: Dexuan Cui , "wei.liu@kernel.org" , KY Srinivasan , Haiyang Zhang , Stephen Hemminger , "linux-hyperv@vger.kernel.org" , "linux-kernel@vger.kernel.org" , vkuznets , "marcelo.cerri@canonical.com" Subject: Re: [PATCH v3] Drivers: hv: vmbus: Add /sys/bus/vmbus/hibernation Message-ID: <20210111110557.bvh6iym7575lgrko@liuwe-devbox-debian-v2> References: <20210107014552.14234-1-decui@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Thu, Jan 07, 2021 at 06:08:51PM +0000, Michael Kelley wrote: > From: Dexuan Cui Sent: Wednesday, January 6, 2021 5:46 PM > > > > 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/hibernation for this purpose. > > > > Signed-off-by: Dexuan Cui [...] > > Reviewed-by: Michael Kelley Queued for hyperv-next. Thanks. Wei. >