From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-fw-80009.amazon.com (smtp-fw-80009.amazon.com [99.78.197.220]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4579B53372; Fri, 3 May 2024 10:14:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=99.78.197.220 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714731274; cv=none; b=Xxpwwpl2/sVteAE4tnelDdmpAUvkVFKfGOUlW/OPw9DtT+b8LvJ+A1LtWNgM6jnB1qrYbe9Pv7E9JXuvWbVf2P2LfitiksscSrS5TaCJrNyf+Ic4bivmoquyiSBvM8BihVsioTJxVTgTODEsADkpX2QJfkTrzA7HX8eAVrRQx3s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714731274; c=relaxed/simple; bh=17qSeGyfDCB1GStmoPezQtiO2dhyRdy/CKq8DCneBHA=; h=Subject:Message-ID:Date:MIME-Version:To:CC:References:From: In-Reply-To:Content-Type; b=Pqzallqgt3qlq08gHBwU/sZUC/XokbG8TXgi4+a+2uUhv8IUXQlymvwFUhOQ5QY76/hmzhRLg2V/oW5I/b1Ff91cPjLGnQjMyMIE5nJPofzncJXBPhEpbht/Vykm6JE9JbcgNhdzipksHbhPgdiAyIbXMGbjCXkdApGt+rlhDWQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.es; spf=pass smtp.mailfrom=amazon.es; dkim=pass (1024-bit key) header.d=amazon.es header.i=@amazon.es header.b=kjIaCDxJ; arc=none smtp.client-ip=99.78.197.220 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.es Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.es Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.es header.i=@amazon.es header.b="kjIaCDxJ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.es; i=@amazon.es; q=dns/txt; s=amazon201209; t=1714731273; x=1746267273; h=message-id:date:mime-version:to:cc:references:from: in-reply-to:content-transfer-encoding:subject; bh=JcL/qLwhid4bdK8Y23Pw20bwrhQLtuNYndPmUZOI95c=; b=kjIaCDxJ3MaJAKNk6oh2befqTBY67qRpZ2S+U1JRLhrCSmRgEetNNglT Ycbu26YfzuyXMP1HsEfOItqXg3Vrakywk5Sp8kZq+oqRAP+AQvnqMFFsz SMegDwjTxXWoKOKv4WQ7SW2/hAcGuqJBUtC10QjCqcvs+XEJ7EYNKBlyw c=; X-IronPort-AV: E=Sophos;i="6.07,251,1708387200"; d="scan'208";a="86564562" Subject: Re: [REGRESSION] Re: [PATCH] Revert "vmgenid: emit uevent when VMGENID updates" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO smtpout.prod.us-east-1.prod.farcaster.email.amazon.dev) ([10.25.36.210]) by smtp-border-fw-80009.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 May 2024 10:14:30 +0000 Received: from EX19MTAEUB002.ant.amazon.com [10.0.43.254:3868] by smtpin.naws.eu-west-1.prod.farcaster.email.amazon.dev [10.0.38.151:2525] with esmtp (Farcaster) id 6c3b5fc8-b2e8-467f-a00a-a1b21b6041fb; Fri, 3 May 2024 10:14:29 +0000 (UTC) X-Farcaster-Flow-ID: 6c3b5fc8-b2e8-467f-a00a-a1b21b6041fb Received: from EX19D037EUB003.ant.amazon.com (10.252.61.119) by EX19MTAEUB002.ant.amazon.com (10.252.51.79) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.28; Fri, 3 May 2024 10:14:29 +0000 Received: from [192.168.6.112] (10.1.213.20) 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 15.2.1258.28; Fri, 3 May 2024 10:14:24 +0000 Message-ID: <9cd37dda-29ea-4a4a-ae43-1cab0449ab0e@amazon.es> Date: Fri, 3 May 2024 12:14:19 +0200 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: "Jason A. Donenfeld" CC: Alexander Graf , , , Greg Kroah-Hartman , Linus Torvalds , Theodore Ts'o , "Cali, Marco" , Arnd Bergmann , "rostedt@goodmis.org" , "Christian Brauner" , , , Lennart Poettering References: <20240418114814.24601-1-Jason@zx2c4.com> Content-Language: en-US From: Babis Chalios In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: EX19D044UWA001.ant.amazon.com (10.13.139.100) To EX19D037EUB003.ant.amazon.com (10.252.61.119) Hi Jason, Friendly ping? IMHO Lennart, Alex and myself have raised (what I think to be) valid technical points regarding your concerns about your belief that the uevent mechanism is an ad-hoc mechanism that you don't consider viable. Just to summarize: * Upon VM clone, user space needs to adjust various components (DHCP leases, MAC addresses, etc.) that have nothing to do with PRNGs. * The path of exposing the VM clone event via vgetrandom() (or any other interface of random.c) is simply wrong. The random subsystem is the natural component to inform about when cached entropy is stale. It should not be responsible for informing user space about VM clone events. IOW, "reseed your PRNGs" is not equivalent to "your VM has been cloned". Given all this, it would help the discussion if you explained why you believe random.c should propagate VM clone events and how. If you don't believe that, could you explain what is the problem with the proposed uevent mechanism? Personally, I agree with Lennart that VMGenID is a generic ACPI device built for exactly this purpose. VMGenID is not an "ad-hoc driver". It is a standard which is supported by most (all?) major VMMs out there today and its whole purpose is to deliver inside the VM a notification that it was cloned. Cheers, Babis