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 651E7C77B6E for ; Wed, 12 Apr 2023 08:02:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229693AbjDLICp (ORCPT ); Wed, 12 Apr 2023 04:02:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229450AbjDLICn (ORCPT ); Wed, 12 Apr 2023 04:02:43 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9CFA59F4; Wed, 12 Apr 2023 01:02:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1681286562; x=1712822562; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=elGtqN9uf2ct4fffBNjNDmoB102spyDxuH+prGf6E1M=; b=Jq9wM6jq6KYanSXIWp2/DcoW/N01mLrCcdAXljrUTp2d2qVbATchg3u/ db9V5Z1ax0TiLaiywW0qfu2RiKEvHyJHYtP+lErxIse05q5WM9vP5RtdI BqZTE2BHzn8SYEwnHMFpUAIdZ7VqDJAVmKg9jiEE7P5oeG4STo/Ynehq/ 0xbXl0yBcXV8kjc4/cSEn2874v+L7emtQJ74XIkYcGSW+RumKS2l6bvf7 9DC3WJHvX6YDg9zHI+Py8tIFXJzncGVdMcOsHBosXBQqI//ISmCIw244v uyX0ZytUclh3GFMqOt92ENe7f4koPByQJ4aERzqO/OZUURGTPGsrv3Nyu g==; X-IronPort-AV: E=McAfee;i="6600,9927,10677"; a="346509412" X-IronPort-AV: E=Sophos;i="5.98,338,1673942400"; d="scan'208";a="346509412" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2023 01:02:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10677"; a="1018660314" X-IronPort-AV: E=Sophos;i="5.98,338,1673942400"; d="scan'208";a="1018660314" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.255.29.206]) ([10.255.29.206]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2023 01:02:38 -0700 Message-ID: Date: Wed, 12 Apr 2023 16:02:37 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.9.1 Subject: Re: [PATCH 1/2] KVM: VMX: Use kvm_read_cr4() to get cr4 value To: Sean Christopherson Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230410125017.1305238-1-xiaoyao.li@intel.com> <20230410125017.1305238-2-xiaoyao.li@intel.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/11/2023 1:11 AM, Sean Christopherson wrote: > On Mon, Apr 10, 2023, Xiaoyao Li wrote: >> Directly use vcpu->arch.cr4 is not recommended since it gets stale value >> if the cr4 is not available. >> >> Use kvm_read_cr4() instead to ensure correct value. >> >> Signed-off-by: Xiaoyao Li >> --- >> arch/x86/kvm/vmx/vmx.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c >> index d7bf14abdba1..befa2486836b 100644 >> --- a/arch/x86/kvm/vmx/vmx.c >> +++ b/arch/x86/kvm/vmx/vmx.c >> @@ -3431,7 +3431,7 @@ static bool vmx_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) >> >> void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) >> { >> - unsigned long old_cr4 = vcpu->arch.cr4; >> + unsigned long old_cr4 = kvm_read_cr4(vcpu); > > Ha! I've been tempted to change this multiple times, but always thought I was > just being a bit obsessive :-) > > Patches look good, but I'm going to hold them for 6.5 just in case this somehow > causes a problem, e.g. if there's a bizzaro nested path that "works" because KVM > _doesn't_ decache info from the current VMCS. so you will put it in kvm-next after 6.4 merge windows?