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 E0F89C3F2C6 for ; Tue, 3 Mar 2020 14:16:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B7EA620838 for ; Tue, 3 Mar 2020 14:16:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bzSew+et" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728592AbgCCOQY (ORCPT ); Tue, 3 Mar 2020 09:16:24 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:58650 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728356AbgCCOQY (ORCPT ); Tue, 3 Mar 2020 09:16:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583244983; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MUTEP1p4YWjzskXYVbK6H4xhC2oS8H6SYOsK8O1eOyQ=; b=bzSew+et0oTss8hF+yTQBV3ff184kWxMigwSUARoJj5M8pUzzw8OvdvNwyYkXVBq0RC6fv EtyYNQRsJ7HXt4pIwoxZPAktxUYSaWkGN12FU/zRdP/Bj7//+1+kOQ7HkkDQokBnwvTSqC mxqH+5vNO0Y3oafmHY8s3JyHiICkpPc= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-275-5TEOS0MJNLqJ4_DgIWdrhA-1; Tue, 03 Mar 2020 09:16:19 -0500 X-MC-Unique: 5TEOS0MJNLqJ4_DgIWdrhA-1 Received: by mail-wr1-f72.google.com with SMTP id f10so1283745wrv.1 for ; Tue, 03 Mar 2020 06:16:19 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=MUTEP1p4YWjzskXYVbK6H4xhC2oS8H6SYOsK8O1eOyQ=; b=LtwYkYGu0iNB3wZSBE2VklLEZ+GkiwKk+Fg4P39y7ClTv6cqSbda6Y8IZBR1jfYz0g 3Mit+w+BgEFkgoMkNvqCHZC4fqEOZ/Tm7d2YCwDt9yvz11+Zo2/hSjghtWS3eq8z8rN1 R8t04l8WIDPPsQEO14Pmdgk+Rk3PiRsIfRaGp/E6mLsyMcOPdtFv3ApnJ/6/aAZBh1mg e9EbjCA8L4fZAysRRw95iORjvjJWm81UststkUQ2sJN2HBK7aOF7inMR0ieUcUorrcDB JPXpj3bujUHgb/SopUgEFluEaFAfk5OIdofawtp9pRtpaB8TsaOk0M4ePh+CYxtXvAal KVWg== X-Gm-Message-State: ANhLgQ383/xFZY7w8z5Qzmg/d6f3bXx7EFYMPWGOIki+MraKyThQ//KO SnqOHPp3kNLNlMeFNowJNz9mMpRShAuukeCNjOCqBrdRWAVY2X+PBCnZyJGk87yPMJvEKiBpa+e YF3qk54CVlPKMUCVfC/U+sS0u X-Received: by 2002:adf:e6c9:: with SMTP id y9mr5857109wrm.246.1583244978784; Tue, 03 Mar 2020 06:16:18 -0800 (PST) X-Google-Smtp-Source: ADFU+vsYNg7+BUQwOf9zvxhDv8luT0LXJFS2Ip7Opm1OZwN8LJ4aJ2q/o6inCPO/0+w/9WVAKxYWiQ== X-Received: by 2002:adf:e6c9:: with SMTP id y9mr5857091wrm.246.1583244978498; Tue, 03 Mar 2020 06:16:18 -0800 (PST) Received: from [192.168.178.40] ([151.20.254.94]) by smtp.gmail.com with ESMTPSA id m25sm2351920wml.35.2020.03.03.06.16.17 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 03 Mar 2020 06:16:18 -0800 (PST) Subject: Re: [PATCH v2 01/66] KVM: x86: Return -E2BIG when KVM_GET_SUPPORTED_CPUID hits max entries To: Sean Christopherson Cc: Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Xiaoyao Li References: <20200302235709.27467-1-sean.j.christopherson@intel.com> <20200302235709.27467-2-sean.j.christopherson@intel.com> From: Paolo Bonzini Message-ID: <599c3a95-a0a6-b31d-56a6-c50971d4ab59@redhat.com> Date: Tue, 3 Mar 2020 15:16:16 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200302235709.27467-2-sean.j.christopherson@intel.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/03/20 00:56, Sean Christopherson wrote: > (KVM hard caps CPUID 0xD at a single sub-leaf). Hmm... no it doesn't? for (idx = 1, i = 1; idx < 64; ++idx) { u64 mask = ((u64)1 << idx); if (*nent >= maxnent) goto out; do_host_cpuid(&entry[i], function, idx); if (idx == 1) { entry[i].eax &= kvm_cpuid_D_1_eax_x86_features; cpuid_mask(&entry[i].eax, CPUID_D_1_EAX); entry[i].ebx = 0; if (entry[i].eax & (F(XSAVES)|F(XSAVEC))) entry[i].ebx = xstate_required_size(supported, true); } else { if (entry[i].eax == 0 || !(supported & mask)) continue; if (WARN_ON_ONCE(entry[i].ecx & 1)) continue; } entry[i].ecx = 0; entry[i].edx = 0; ++*nent; ++i; } I still think the patch is correct, what matters is that no KVM in existence supports enough processor features to reach 100 or so subleaves. Paolo