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 05CF3C433F5 for ; Fri, 25 Feb 2022 14:33:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232613AbiBYOe3 (ORCPT ); Fri, 25 Feb 2022 09:34:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231965AbiBYOe2 (ORCPT ); Fri, 25 Feb 2022 09:34:28 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E8942763E2; Fri, 25 Feb 2022 06:33:56 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 286CDB831F9; Fri, 25 Feb 2022 14:33:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 251F1C340E7; Fri, 25 Feb 2022 14:33:51 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="GS3fWtqB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1645799629; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=f7l+1znU0C3mGGUO232V1hcf63PeBIQ9HzasOLJsYSs=; b=GS3fWtqB1bIfgIGI51lS8j8ppgTmfWTnL/BLepHrXEWwGTqQkEnfaG0h2EEPE85kqfIYBc VEyZFu5mJGLEAB/T3OffmgHyhyZjZy5IC048I+OZLJ6gDvbCfB/dSktTa0JfsIgqEOxi7a P/XMxf5+izlbzRbSgUBu4cryEdBDZHk= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id ffcd5017 (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO); Fri, 25 Feb 2022 14:33:49 +0000 (UTC) Date: Fri, 25 Feb 2022 15:33:44 +0100 From: "Jason A. Donenfeld" To: Alexander Graf Cc: kvm@vger.kernel.org, linux-crypto@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, adrian@parity.io, ardb@kernel.org, ben@skyportsystems.com, berrange@redhat.com, colmmacc@amazon.com, decui@microsoft.com, dwmw@amazon.co.uk, ebiggers@kernel.org, ehabkost@redhat.com, gregkh@linuxfoundation.org, haiyangz@microsoft.com, imammedo@redhat.com, jannh@google.com, kys@microsoft.com, lersek@redhat.com, linux@dominikbrodowski.net, mst@redhat.com, qemu-devel@nongnu.org, raduweis@amazon.com, sthemmin@microsoft.com, tytso@mit.edu, wei.liu@kernel.org Subject: Re: [PATCH v4] virt: vmgenid: introduce driver for reinitializing RNG on VM fork Message-ID: References: <20220225124848.909093-1-Jason@zx2c4.com> <05c9f2a9-accb-e0de-aac7-b212adac7eb2@amazon.com> <88ebdc32-2e94-ef28-37ed-1c927c12af43@amazon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <88ebdc32-2e94-ef28-37ed-1c927c12af43@amazon.com> Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Fri, Feb 25, 2022 at 03:18:43PM +0100, Alexander Graf wrote: > > I recall this part of the old thread. From what I understood, using > > "VMGENID" + "QEMUVGID" worked /well enough/, even if that wasn't > > technically in-spec. Ard noted that relying on _CID like that is > > technically an ACPI spec notification. So we're between one spec and > > another, basically, and doing "VMGENID" + "QEMUVGID" requires fewer > > changes, as mentioned, appears to work fine in my testing. > > > > However, with that said, I think supporting this via "VM_Gen_Counter" > > would be a better eventual thing to do, but will require acks and > > changes from the ACPI maintainers. Do you think you could prepare your > > patch proposal above as something on-top of my tree [1]? And if you can > > convince the ACPI maintainers that that's okay, then I'll happily take > > the patch. > > > Sure, let me send the ACPI patch stand alone. No need to include the > VMGenID change in there. That's fine. If the ACPI people take it for 5.18, then we can count on it being there and adjust the vmgenid driver accordingly also for 5.18. I just booted up a Windows VM, and it looks like Hyper-V uses "Hyper_V_Gen_Counter_V1", which is also quite long, so we can't really HID match on that either. Jason