From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 956483451D1; Wed, 12 Nov 2025 18:24:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762971883; cv=none; b=WjOFUPcS4QKABRkxTq9OoObWaJOlaD4aq3gbGWMy8h8GoH/BS88x2rJdSf1cy6qMC63Es703AsvoDb7cQ/lUhqQZWOk0QZwpfdNDDKxgWrIXukXUKjow9v3vNXOzWTvtxrGtEJdO+sIY6HUgsIpuSXXOWSbvosrpcKI5OTD4MdM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762971883; c=relaxed/simple; bh=IWByMhcBEVGO1q2CUX2wnKZSyBUhuihycTfOsSlR/O8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Fz9jjsko2EPYYnXuF89Fk0zfqAu38q/25/xkxprYdQcSzy1KZfgtNRH3fiGAEaJAHLffgPscUUaQQl7A7fM8cbCODvpL9+8m6XQjTJ2PV9gDtDccBtGfpZDQbfObPSIVqL1pqaxJ7ZP2QK0pZQvqvlM/hFVRQVklesi2En1txas= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Ino744AJ; arc=none smtp.client-ip=198.175.65.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Ino744AJ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1762971882; x=1794507882; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=IWByMhcBEVGO1q2CUX2wnKZSyBUhuihycTfOsSlR/O8=; b=Ino744AJ8NPcXDIdiisz2fEUynuqEZtBxQd75K0w7Se92pEnBW/1ewDg g2j4qdKg8ngiWipb9cehXgrNedZFUL+2j5HrnOdFGSn++8UEUWP1AehW5 i55vkAp36KKhdz2i2MRsbWbG9h7TxkvKrlUsmdvNuHjaHLQU8oiqzrqG7 HcM1+B+2ECK5OzlVGFG3ACYNKADXWxSNxtP9mHl+cV9RxnKTT1t+hp40H 2p4fz7DUcr1FzA+kSmliix5T3NH0Oh4TaFEC2eONnVtT9U/xZWx/bI9P5 HBM+Q6qPXcO7yWg7Y8QDkL/8koBRwt5XNWrQuCWZYMz7urlEvV7KsrRfE A==; X-CSE-ConnectionGUID: YwvNZ16nR4C45j9rzmaMIw== X-CSE-MsgGUID: ZdPHkW33TPampU9Qw1ec3w== X-IronPort-AV: E=McAfee;i="6800,10657,11611"; a="76503000" X-IronPort-AV: E=Sophos;i="6.19,300,1754982000"; d="scan'208";a="76503000" Received: from fmviesa006.fm.intel.com ([10.60.135.146]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Nov 2025 10:24:41 -0800 X-CSE-ConnectionGUID: RlvbgsRNSJe30YkqPUgNLw== X-CSE-MsgGUID: K9OyEaFbSsWoa1nTotGOkQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,300,1754982000"; d="scan'208";a="189136444" Received: from guptapa-desk.jf.intel.com (HELO desk) ([10.165.239.46]) by fmviesa006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Nov 2025 10:24:41 -0800 Date: Wed, 12 Nov 2025 10:24:35 -0800 From: Pawan Gupta To: Borislav Petkov Cc: Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Peter Zijlstra , Josh Poimboeuf , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Brendan Jackman Subject: Re: [PATCH v4 3/8] x86/bugs: Use an X86_FEATURE_xxx flag for the MMIO Stale Data mitigation Message-ID: <20251112182435.od5oelwiitdueork@desk> References: <20251031003040.3491385-1-seanjc@google.com> <20251031003040.3491385-4-seanjc@google.com> <20251112144655.GZaRSd32GC0lZdDOWg@fat_crate.local> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251112144655.GZaRSd32GC0lZdDOWg@fat_crate.local> On Wed, Nov 12, 2025 at 03:46:55PM +0100, Borislav Petkov wrote: > > diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h > > index 7129eb44adad..d1d7b5ec6425 100644 > > --- a/arch/x86/include/asm/cpufeatures.h > > +++ b/arch/x86/include/asm/cpufeatures.h > > @@ -501,6 +501,7 @@ > > #define X86_FEATURE_ABMC (21*32+15) /* Assignable Bandwidth Monitoring Counters */ > > #define X86_FEATURE_MSR_IMM (21*32+16) /* MSR immediate form instructions */ > > #define X86_FEATURE_X2AVIC_EXT (21*32+17) /* AMD SVM x2AVIC support for 4k vCPUs */ > > +#define X86_FEATURE_CLEAR_CPU_BUF_MMIO (21*32+18) /* Clear CPU buffers using VERW before VMRUN, iff the vCPU can access host MMIO*/ > ^^^^^^^ > > Yes, you can break the line and format it properly. :-) > > Also, this should be called then > > X86_FEATURE_CLEAR_CPU_BUF_VM_MMIO > > as it is a VM-thing too. +1. This is a VM-only flag.