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=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 913DAC43460 for ; Thu, 8 Apr 2021 16:28:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5E49B61104 for ; Thu, 8 Apr 2021 16:28:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232296AbhDHQ2n (ORCPT ); Thu, 8 Apr 2021 12:28:43 -0400 Received: from smtp-fw-4101.amazon.com ([72.21.198.25]:19501 "EHLO smtp-fw-4101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231918AbhDHQ2m (ORCPT ); Thu, 8 Apr 2021 12:28:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.de; i=@amazon.de; q=dns/txt; s=amazon201209; t=1617899311; x=1649435311; h=date:from:to:cc:message-id:references:mime-version: in-reply-to:subject; bh=nMOUzFDnk5fm+FTvgXSXFX2ZDTXd0y1hb+al8HGRTjE=; b=nF+GNRsNoY/zGPG3j27/0yOIJsyzWr33KkbUq2tG81mo9YxJFJU6jmGO j0Gfs6xf4kK3AQFel4v/LUxfPyOcZgVhQJwFLTbZChkcta8ZeOaGx7Aa7 Y73uvtq6uqNng8lxRCWoAFyfbPyMOmNkm59oCo5ZMitBXY7ez7zfzeg4I 0=; X-IronPort-AV: E=Sophos;i="5.82,206,1613433600"; d="scan'208";a="100469738" Subject: Re: [PATCH 0/4] Add support for XMM fast hypercalls Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-1a-807d4a99.us-east-1.amazon.com) ([10.43.8.2]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 08 Apr 2021 16:21:21 +0000 Received: from EX13D28EUC003.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan2.iad.amazon.com [10.40.163.34]) by email-inbound-relay-1a-807d4a99.us-east-1.amazon.com (Postfix) with ESMTPS id 1CB9CA1E52; Thu, 8 Apr 2021 16:21:14 +0000 (UTC) Received: from u366d62d47e3651.ant.amazon.com (10.43.160.209) by EX13D28EUC003.ant.amazon.com (10.43.164.43) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 8 Apr 2021 16:21:07 +0000 Date: Thu, 8 Apr 2021 18:21:03 +0200 From: Siddharth Chandrasekaran To: Wei Liu CC: Paolo Bonzini , , , , , , , , , , , , , , , , , , Message-ID: <20210408162102.GE32315@u366d62d47e3651.ant.amazon.com> References: <20210407212926.3016-1-sidcha@amazon.de> <20210408152817.k4d4hjdqu7hsjllo@liuwe-devbox-debian-v2> <033e7d77-d640-2c12-4918-da6b5b7f4e21@redhat.com> <20210408153813.iu3teoor6c6m6kzb@liuwe-devbox-debian-v2> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20210408153813.iu3teoor6c6m6kzb@liuwe-devbox-debian-v2> User-Agent: Mutt/1.9.4 (2018-02-28) X-Originating-IP: [10.43.160.209] X-ClientProxiedBy: EX13D49UWB001.ant.amazon.com (10.43.163.72) To EX13D28EUC003.ant.amazon.com (10.43.164.43) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 08, 2021 at 03:38:13PM +0000, Wei Liu wrote: > On Thu, Apr 08, 2021 at 05:30:26PM +0200, Paolo Bonzini wrote: > > On 08/04/21 17:28, Wei Liu wrote: > > > > Although the Hyper-v TLFS mentions that a guest cannot use this feature > > > > unless the hypervisor advertises support for it, some hypercalls which > > > > we plan on upstreaming in future uses them anyway. > > > > > > No, please don't do this. Check the feature bit(s) before you issue > > > hypercalls which rely on the extended interface. > > > > Perhaps Siddharth should clarify this, but I read it as Hyper-V being buggy > > and using XMM arguments unconditionally. > > > > There is no code in upstream Linux that uses the XMM fast hypercall > interface at the moment. > > If there is such code, it has bugs in it and should be fixed. :-) None of the existing hypercalls are buggy. These are some hypercalls we are working on (and planning on upstreaming in the near future). ~ Sid. Amazon Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B Sitz: Berlin Ust-ID: DE 289 237 879