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=-2.4 required=3.0 tests=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 62DC3C433E1 for ; Fri, 29 May 2020 11:13:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3D979208A7 for ; Fri, 29 May 2020 11:13:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="J1VZZMPE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725971AbgE2LNR (ORCPT ); Fri, 29 May 2020 07:13:17 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:36691 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725681AbgE2LNQ (ORCPT ); Fri, 29 May 2020 07:13:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590750795; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=k3AfmsRT0TiIWR7m+9uIgkkFYc4AqBIq+Eofk3eZmvk=; b=J1VZZMPENFGU0+7E2txoMPVKSPiBWkfhA2E+YSmf0NpgY91eR3gpgE6PEDn2FnyFHK7t4k Qzt720LXK+DGP5jsi6qZzzIHGAJeKbNbNpIYF1HQRF7eHxF02zfeI4ftjBf+1EqgGgp7IP W/SzqudKYFbfhA72oVg0/rDib1bN9w0= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-215-4_K6rw-3OLCgwv-TECwi_A-1; Fri, 29 May 2020 07:13:12 -0400 X-MC-Unique: 4_K6rw-3OLCgwv-TECwi_A-1 Received: by mail-wm1-f69.google.com with SMTP id b65so551186wmb.5 for ; Fri, 29 May 2020 04:13:11 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=k3AfmsRT0TiIWR7m+9uIgkkFYc4AqBIq+Eofk3eZmvk=; b=EG4LBgYXoHHbboo4f63JC1B4irEkgrGn2bByREEsRoGFQtjN/TuWolNJjBF2I6K5Aw A/PNwerjTDvyoUfg8ukktSMfH4lRn8kq1fx0vuhoOWeh9FZHVpnHYkDcbLhMskCs3YOj dORv3b01JriNt7yz0xGXpM18WRICLeZmpg1mV02JkEWwfDZxRNeRG7mVV7Aqa3SJHwBB 4oBILGrgTBghsJAGNckrH8PIg1ARjnDO3SLctDHkX5caJBHuY/b+6nGoY2LGQHsZYE6h 9sK6U7GcHO/BvBf0mx7Owz15Vp1Ss/zJea1RImeD8gAXYoUEQ1Frqay3SebLgyYQlpAm 41wA== X-Gm-Message-State: AOAM533heFYMYI4Xu5u2H0WC0AvOuv54hxSlvpblEUJVliAuUhUfgnNi cXAL2x1PXAzezd71rqzg60BlC9Uums3rTEwUUd8l35Appr9n2ygQ/pJ+w+w18kieBP69en9gEpA Gd9UQgdLUkWz+b3ZzX+cPt0+2 X-Received: by 2002:adf:9f0b:: with SMTP id l11mr4003804wrf.66.1590750790967; Fri, 29 May 2020 04:13:10 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwDYEHrheOkcfEc2jUohO+GtONYKzeGu2Vjgv978rRE4MKHlxn9rxABO3lp12HN2dFuTClPmA== X-Received: by 2002:adf:9f0b:: with SMTP id l11mr4003778wrf.66.1590750790711; Fri, 29 May 2020 04:13:10 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:b096:1b7:7695:e4f7? ([2001:b07:6468:f312:b096:1b7:7695:e4f7]) by smtp.gmail.com with ESMTPSA id u130sm10768318wmg.32.2020.05.29.04.13.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 29 May 2020 04:13:10 -0700 (PDT) Subject: Re: [PATCH v11 2/7] x86/kvm/hyper-v: Simplify addition for custom cpuid leafs To: Jon Doron , Roman Kagan , kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, vkuznets@redhat.com References: <20200424113746.3473563-1-arilou@gmail.com> <20200424113746.3473563-3-arilou@gmail.com> <20200513092404.GB29650@rvkaganb.lan> <20200513124915.GM2862@jondnuc> From: Paolo Bonzini Message-ID: Date: Fri, 29 May 2020 13:13:09 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200513124915.GM2862@jondnuc> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On 13/05/20 14:49, Jon Doron wrote: >> > > To be honest from my understanding of the TLFS it states: > "The maximum input value for hypervisor CPUID information." > > So we should not expose stuff we wont "answer" to, I agree you can > always issue CPUID to any leaf and you will get zeroes but if we try to > follow TLFS it sounds like this needs to be capped here. I think Roman is right in the reading, but it's also nicer to have a capped EAX because you can just look at EAX and guess what features are there (it's simpler than looking for zeroes). Paolo