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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7CFB7C7EE25 for ; Wed, 7 Jun 2023 12:21:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240700AbjFGMV3 (ORCPT ); Wed, 7 Jun 2023 08:21:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35052 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240701AbjFGMVO (ORCPT ); Wed, 7 Jun 2023 08:21:14 -0400 Received: from smtp-fw-80008.amazon.com (smtp-fw-80008.amazon.com [99.78.197.219]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F1241BFD; Wed, 7 Jun 2023 05:21:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.es; i=@amazon.es; q=dns/txt; s=amazon201209; t=1686140471; x=1717676471; h=message-id:date:mime-version:to:cc:references:from: in-reply-to:content-transfer-encoding:subject; bh=H+lCeGmcbHRGOxfwB4VQbIsL3x2USb4Et2eGWZ5GoBY=; b=fM9M0cg/ohiKDT37b5MwJUJ/LqolH4qoq2rL904eo35BAu23WD5yiE5c pQ1YRJBthnspYO4l/EMV86kG9iAjfUFzrqSKiIFjB0z+kU/BZDbBXPbVI mYpgau7uEEy4u87LRgFZZ5PeJABgySKpQLgUsAvV2WJSfJPb64MPY3Q0+ s=; X-IronPort-AV: E=Sophos;i="6.00,224,1681171200"; d="scan'208";a="8708734" Subject: Re: [ANNOUNCE] KVM Microconference at LPC 2023 Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO email-inbound-relay-iad-1d-m6i4x-00fceed5.us-east-1.amazon.com) ([10.25.36.210]) by smtp-border-fw-80008.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jun 2023 12:21:08 +0000 Received: from EX19D013EUA003.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan3.iad.amazon.com [10.40.163.38]) by email-inbound-relay-iad-1d-m6i4x-00fceed5.us-east-1.amazon.com (Postfix) with ESMTPS id AAD46A2A8C; Wed, 7 Jun 2023 12:21:05 +0000 (UTC) Received: from EX19D037EUB003.ant.amazon.com (10.252.61.119) by EX19D013EUA003.ant.amazon.com (10.252.50.72) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Wed, 7 Jun 2023 12:21:05 +0000 Received: from [192.168.30.121] (10.1.212.27) by EX19D037EUB003.ant.amazon.com (10.252.61.119) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Wed, 7 Jun 2023 12:21:02 +0000 Message-ID: Date: Wed, 7 Jun 2023 14:20:57 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.11.2 Content-Language: en-US To: Paolo Bonzini , KVM list , "linux-kernel@vger.kernel.org" CC: Sean Christopherson , Marc Zyngier , Alexander Graf , "Cali, Marco" References: <2f19f26e-20e5-8198-294e-27ea665b706f@redhat.com> <150e1ad0-3d59-762b-6032-897d5630a3bf@amazon.es> <5283b17c-185b-a37f-84e2-dcd08e042ec0@redhat.com> From: Babis Chalios In-Reply-To: <5283b17c-185b-a37f-84e2-dcd08e042ec0@redhat.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.1.212.27] X-ClientProxiedBy: EX19D039UWA002.ant.amazon.com (10.13.139.32) To EX19D037EUB003.ant.amazon.com (10.252.61.119) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/6/23 12:37, Paolo Bonzini wrote: > CAUTION: This email originated from outside of the organization. Do > not click links or open attachments unless you can confirm the sender > and know the content is safe. > > > > On 6/7/23 12:13, Babis Chalios wrote: >> >> >> On our side, we 've been working on providing ways to let VMs (kernel >>  and user space) know that they have been cloned/snapshotted/restored >> from snapshots[1]. >> >> This is tightly coupled with PRNGs both in kernel and user space and >>  there needs to be some collaboration with random.c to tie everything >> together [2][3]. It sounds like it could be a good fit for this MC >> (?). > > Does the VM generation ID ACPI device from Microsoft work for you?  It > is not tied to Hyper-V. > > Paolo > It's a long story :P TLDR: For some use-cases it should be enough [1]. For PRNGs though it doesn't seem to work as is. (1) The Linux implementation of VMGENID is racy and (2) last year there were long discussions related to the user-space ABI, which diverged us away from it. BTW, just saw that you have already submitted the proposal for the MC, sorry for being late :) Cheers, Babis