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 60BB5C8300C for ; Wed, 7 Jun 2023 20:21:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233030AbjFGUVn (ORCPT ); Wed, 7 Jun 2023 16:21:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46790 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232934AbjFGUVg (ORCPT ); Wed, 7 Jun 2023 16:21:36 -0400 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6B5CD2695; Wed, 7 Jun 2023 13:21:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1686169269; x=1717705269; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=Iy80am0IjcpZU5wkeaklTCrSRzUJtl7rEeZ5aEG4RTs=; b=hV6T+AM77usMgUi5R3al4ehA6BX+o6w/J1ukHZk6tbevzhkwho5a2A9S o8Gdi/JufHbm5GIzEKKWxIqA/Y48Xz6LonxEQOsej0XTaEQ3KxoLn6Qrm vgimHPZewN1cbwEvknZX2Xb9Sof/dXSIFo1RiICKPmRmcmXQGM4f5Not2 DGTraAhRKpIIO1e4LjDzjS6l6Qm5QjNpTSWc9RQfpNO3B9qLDY9e8rLey 0MhtGH9SnWFWXA0Pd2ngtTlq9EnM+0vE3lyoSC3WkXdKrljw13ubquyjF j1LD0NG76eZ1eouqb66aownbdQtnmg3YLaImFo8N3RmpWw1FBCp/6B02i A==; X-IronPort-AV: E=McAfee;i="6600,9927,10734"; a="337460732" X-IronPort-AV: E=Sophos;i="6.00,225,1681196400"; d="scan'208";a="337460732" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jun 2023 13:20:45 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10734"; a="774766041" X-IronPort-AV: E=Sophos;i="6.00,225,1681196400"; d="scan'208";a="774766041" Received: from unknown (HELO desk) ([10.255.231.181]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jun 2023 13:20:44 -0700 Date: Wed, 7 Jun 2023 13:20:38 -0700 From: Pawan Gupta To: Sean Christopherson Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Gao , Xiaoyao Li Subject: Re: [PATCH 2/2] KVM: VMX: Drop unnecessary vmx_fb_clear_ctrl_available "cache" Message-ID: <20230607202038.5vsgsrt724qhxnjd@desk> References: <20230607004311.1420507-1-seanjc@google.com> <20230607004311.1420507-3-seanjc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230607004311.1420507-3-seanjc@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 06, 2023 at 05:43:10PM -0700, Sean Christopherson wrote: > Now that KVM snapshots the host's MSR_IA32_ARCH_CAPABILITIES, drop the > similar snapshot/cache of whether or not KVM is allowed to manipulate > ARCH_CAPABILITIES.FB_CLEAR_CTRL. The motivation for the cache was FB_CLEAR_CTRL is a read-only bit, I think you mean MSR_IA32_MCU_OPT_CTRL.FB_CLEAR_DIS. > presumably to avoid the RDMSR, e.g. boot_cpu_has_bug() is quite cheap, and > modifying the vCPU's MSR_IA32_ARCH_CAPABILITIES is an infrequent option > and a relatively slow path. > > Cc: Pawan Gupta > Signed-off-by: Sean Christopherson LGTM. Reviewed-by: Pawan Gupta