From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-177322-1519049254-2-14026113998708552982 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no ("Email failed DMARC policy for domain") X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org' X-Spam-charsets: cc='UTF-8', plain='utf-8' X-IgnoreVacation: yes ("Email failed DMARC policy for domain") X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519049253; b=Q+urCHvF250R8UTOFs28MwuVkYdeEoGRVWRA8jmC3s14dzF 5Luwzn75jALETMGWftYfJazSgoCDzyM2mD9EFSb7p4Oowqz1zsMW/Ak+NH4+gIUd PZVE20Js/RlZBC0XVrWtqzjuBeZEehoiqMu6nnWF7LKug4qhSc1QsPkpRwr9tPpr PGRhwaclYzOBrxSitjILFAYtIjbuN3ijO6tQK/zYUIfgzrmbm+jSFBw7HBZU3H00 f48G7ZetSGAa1JIrOjV4SefeSIz5WZbrsKl+rfAvdCqDj5PIRpv6Zpk1pvdW18EZ aiHK+Pog2zMnDnug/RFwlyOxz5d1k5w+/SvlJxA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=subject:to:cc:references:from:message-id :date:mime-version:in-reply-to:content-type :content-transfer-encoding:sender:list-id; s=arctest; t= 1519049253; bh=zmXUSjRKdk2Oh3GAHPf+Xs4J9ivVcqzbLqt99MIsLEY=; b=i uV96t6fdJI0RNebrvN7a7oQwtHkHAIrp2OiG4+sR0/c4d3AH0bGtYPLlOe1dzOvm uhBcmgVhVivcwwjZOWQWJ+00lVsJ8+Sy/JmauCv95Ha4xu5RmVepFE62nhIxIz06 cKkEwf5FyTmSQ23gwRoXLAFuSaBBYbLfpucm5l3ypbsW0b+8BJemDvPX20aKTc9l ZFyJ9fH8Chek/3aRJqK48Id8n++N7K1Oo92ApucVtr7SXh27omqxl/ZpQWrW9m5n lu5XrbzJEZ4CJrJhV5+JBtHhjVYv7v2R48dfyqQh4jQUwFTGHEzUeuniQL9fV4xM 1S8Iz7uqslb0t9Gul/4GQ== ARC-Authentication-Results: i=1; mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=fail (p=none,has-list-id=yes,d=none) header.from=redhat.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=redhat.com header.result=pass header_is_org_domain=yes Authentication-Results: mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=fail (p=none,has-list-id=yes,d=none) header.from=redhat.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=redhat.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751447AbeBSOHQ (ORCPT ); Mon, 19 Feb 2018 09:07:16 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56752 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750998AbeBSOHP (ORCPT ); Mon, 19 Feb 2018 09:07:15 -0500 Subject: Re: [PATCH 7/9] KVM/VMX: Emulate MSR_IA32_ARCH_CAPABILITIES To: David Woodhouse , Jim Mattson Cc: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , LKML , kvm list , KarimAllah Ahmed , Greg Kroah-Hartman , stable@vger.kernel.org References: <1517938181-15317-1-git-send-email-dwmw@amazon.co.uk> <1517938181-15317-8-git-send-email-dwmw@amazon.co.uk> <4be4e462-61be-53a9-b0e1-3508466d1645@redhat.com> <1519047329.7876.64.camel@infradead.org> From: Paolo Bonzini Message-ID: <6ef598e6-de89-abdb-f157-dc12bb24ef9d@redhat.com> Date: Mon, 19 Feb 2018 15:07:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <1519047329.7876.64.camel@infradead.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 19/02/2018 14:35, David Woodhouse wrote: > On Mon, 2018-02-19 at 14:10 +0100, Paolo Bonzini wrote: >>> Hardware seems like a reasonable place to get the default value (cf. >>> the VMX capability MSRs). >> >> There are some differences: >> >> - a zero value for ARCH_CAPABILITIES should be safe, while a zero value >> for VMX capabilities doesn't really make sense.  On the contrary, a >> nonzero value for ARCH_CAPABILITIES is not safe across live migration. > > Any VMM which is going to support live migration surely needs to pay at > least a small amount of attention to the features it exposes? Exposing > the ARCH_CAPABILITIES CPUID bit without actually looking at the > contents of the associated MSR which that bit advertises would be... a > little strange, would it not?  I think what we should do is simply backport Tom Lendacky's series to 4.14 and 4.9 ASAP, and add ARCH_CAPABILITIES support there. Then the question of the default becomes moot, more or less. Paolo > I don't see why we care so much about the *default* value, in that > context.