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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE2DAC61DA4 for ; Thu, 16 Feb 2023 05:31:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229583AbjBPFbu (ORCPT ); Thu, 16 Feb 2023 00:31:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229740AbjBPFbs (ORCPT ); Thu, 16 Feb 2023 00:31:48 -0500 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 791791BEC for ; Wed, 15 Feb 2023 21:31:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1676525506; x=1708061506; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=YpGGjxXBgRUXDWZRTTAVOSNDs0rn3lq38WRq/zKWQkY=; b=H/qcJZjK1WBbUdBBshW1OClheLYVLFfkPjkHxBY7PO/0TAjwrzSh3bGB +q0HjntbZmItPXMV8moSsr4jjZkEvt80XLjR0X903jHj15FI+rVtzVFoU 7sXaOXIfUlODGkIx5BY1IUsxnW3SaWaAF064UmwFOtPTDUDNfhG8zcmDA X25pX1ujS3y5WZQ6kVJgdz+OYOnO7BAxr6z1+hAhYj5oIzQkz0rqWfTN8 Q+SvbTk3cGktbaXj2c62ois8EQc4ntiEaKto/2bcxGRVwIT5PBDRcfsRm 36GL7S69jkLNmy/gSvVjqhNEXJYPvzauP2f1/0t5aRx15Ocie2b42nnpX g==; X-IronPort-AV: E=McAfee;i="6500,9779,10622"; a="333794743" X-IronPort-AV: E=Sophos;i="5.97,301,1669104000"; d="scan'208";a="333794743" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Feb 2023 21:31:45 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10622"; a="702440244" X-IronPort-AV: E=Sophos;i="5.97,301,1669104000"; d="scan'208";a="702440244" Received: from binbinwu-mobl.ccr.corp.intel.com (HELO [10.238.1.250]) ([10.238.1.250]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Feb 2023 21:31:41 -0800 Message-ID: <264acaa2-ba77-685b-04c3-35e4c7db52f0@linux.intel.com> Date: Thu, 16 Feb 2023 13:31:39 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.7.2 Subject: Re: [PATCH v4 1/9] KVM: x86: Intercept CR4.LAM_SUP when LAM feature is enabled in guest To: Robert Hoo , seanjc@google.com, pbonzini@redhat.com, yu.c.zhang@linux.intel.com, yuan.yao@linux.intel.com, jingqi.liu@intel.com, weijiang.yang@intel.com, chao.gao@intel.com, isaku.yamahata@intel.com Cc: kirill.shutemov@linux.intel.com, kvm@vger.kernel.org References: <20230209024022.3371768-1-robert.hu@linux.intel.com> <20230209024022.3371768-2-robert.hu@linux.intel.com> <814481b6-c316-22bd-2193-6aa700db47b5@linux.intel.com> <90d0f1ffec67e015e3f0f1ce9d8d719634469a82.camel@linux.intel.com> <1e8df25a-4c25-6738-dd92-a58c28282eb0@linux.intel.com> From: Binbin Wu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2/14/2023 8:24 PM, Robert Hoo wrote: > On Tue, 2023-02-14 at 17:00 +0800, Binbin Wu wrote: >> According to the code of set_cr4_guest_host_mask, >> vcpu->arch.cr4_guest_owned_bits is a subset of >> KVM_POSSIBLE_CR4_GUEST_BITS, >> and X86_CR4_LAM_SUP is not included in KVM_POSSIBLE_CR4_GUEST_BITS. >> No matter change CR4_RESERVED_BITS or not, X86_CR4_LAM_SUP will >> always be set in CR4_GUEST_HOST_MASK. >> >> > set_cr4_guest_host_mask(): > vcpu->arch.cr4_guest_owned_bits = KVM_POSSIBLE_CR4_GUEST_BITS & > ~vcpu->arch.cr4_guest_rsvd_bits; My point is  when X86_CR4_LAM_SUP is not set in KVM_POSSIBLE_CR4_GUEST_BITS, CR4.LAM_SUP is definitely owned by host, regardless of the value of cr4_guest_rsvd_bits. > > kvm_vcpu_after_set_cpuid(): > vcpu->arch.cr4_guest_rsvd_bits = > __cr4_reserved_bits(guest_cpuid_has, vcpu); >