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=-4.0 required=3.0 tests=BAYES_00,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 B9514C433B4 for ; Thu, 8 Apr 2021 16:30:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8823A61105 for ; Thu, 8 Apr 2021 16:30:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232346AbhDHQae (ORCPT ); Thu, 8 Apr 2021 12:30:34 -0400 Received: from mail-wr1-f49.google.com ([209.85.221.49]:45659 "EHLO mail-wr1-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231480AbhDHQac (ORCPT ); Thu, 8 Apr 2021 12:30:32 -0400 Received: by mail-wr1-f49.google.com with SMTP id f6so2782960wrv.12; Thu, 08 Apr 2021 09:30:20 -0700 (PDT) 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; bh=F496zTMs/cLiMo2b9mYzLgl9Z8QdoE+o/DNCzI6MgkY=; b=qRmKp29Gbu+abI/zgMqwuTPIfNkSniOCrevF7rnMsgFFGPxPcJxOZ9RpKOY2Koh5uN 50ROeQdI9VoyUeMMhAA1dJRh1dyk542xCzdMS1XtiM+Pr37/nQkZghrR0skWx4CSve2L zdhGWbN+TR+sNd2HsF/5ly+AMJKv7zqwrVXHVRaxhmEJwTvk14KvpqyhIoiW0YK9Cshs /vvq763CYp/MJFQK7ULm33ID+urfqWcjFJ3mpqyNCZSeVMinR1MNnQTDKEJg95ilH6u6 NeagzcC2u96Y5NmEA4T0gtHPFrtcd/l5PWJ9aKjDB3Ky0q/hbR+2shNbGZVVDHndU/GV IWTA== X-Gm-Message-State: AOAM533/Naj2kGCSoAqo7ctK7+mWjtiSG2M+Zmw0v+tErWgr2Ff7j0yp iaUmJpBWO7413i3KozkTGgc= X-Google-Smtp-Source: ABdhPJzu9VwCOtcF4a86gsoB2sZ59A2GDYEVvAXWTOc+xe3vNUmDqkMYDVTfktJ9g6vHQhOeXj1OXA== X-Received: by 2002:adf:e38a:: with SMTP id e10mr12738849wrm.37.1617899420267; Thu, 08 Apr 2021 09:30:20 -0700 (PDT) Received: from liuwe-devbox-debian-v2 ([51.145.34.42]) by smtp.gmail.com with ESMTPSA id o14sm39776289wrh.88.2021.04.08.09.30.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Apr 2021 09:30:20 -0700 (PDT) Date: Thu, 8 Apr 2021 16:30:18 +0000 From: Wei Liu To: Siddharth Chandrasekaran Cc: Paolo Bonzini , Wei Liu , kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, seanjc@google.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, graf@amazon.com, eyakovl@amazon.de, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH 0/4] Add support for XMM fast hypercalls Message-ID: <20210408163018.mlr23jd2r4st54jc@liuwe-devbox-debian-v2> References: <20210407212926.3016-1-sidcha@amazon.de> <20210408152817.k4d4hjdqu7hsjllo@liuwe-devbox-debian-v2> <033e7d77-d640-2c12-4918-da6b5b7f4e21@redhat.com> <20210408154006.GA32315@u366d62d47e3651.ant.amazon.com> <53200f24-bd57-1509-aee2-0723aa8a3f6f@redhat.com> <20210408155442.GC32315@u366d62d47e3651.ant.amazon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210408155442.GC32315@u366d62d47e3651.ant.amazon.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 08, 2021 at 05:54:43PM +0200, Siddharth Chandrasekaran wrote: > On Thu, Apr 08, 2021 at 05:48:19PM +0200, Paolo Bonzini wrote: > > On 08/04/21 17:40, Siddharth Chandrasekaran 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. > > > The guest is at fault here as it expects Hyper-V to consume arguments > > > from XMM registers for certain hypercalls (that we are working) even if > > > we didn't expose the feature via CPUID bits. > > > > What guest is that? > > It is a Windows Server 2016. Can you be more specific? Are you implementing some hypercalls from TLFS? If so, which ones? Wei.