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 2F4A0C433F5 for ; Tue, 12 Apr 2022 18:11:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350639AbiDLSNw (ORCPT ); Tue, 12 Apr 2022 14:13:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358646AbiDLSNs (ORCPT ); Tue, 12 Apr 2022 14:13:48 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F6DF4968E; Tue, 12 Apr 2022 11:11:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1649787090; x=1681323090; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=e+v9atRUEsNxr7cIqFOK0n4ysOpxO9O67Ox4EDhcAKY=; b=K6x0jezJZy9FPx5cQ4ZLGr4gynE/sdwhh/Kkasfny9BBzvg+crNcgyKp llHRFDByU1k2dXiFDW1M10FSnBctn9t5vLTmJXjkT4VQ8HfcPTBKCXytP qMpqTLHBf30gXW3l3Tm2oSHjiDKnyfGrjV+QuuqI3SNEdssuh9O2wPSFA NVsANBSYW8nXagxq124jI9VS/MUf0VKxiIxOncHRpog9izl2iEbHVHysi 2KBZmUsyWbA7XBJ2A9Gt0nTdU7vGD925SjggpnoacUtDcnVImIC2ewq2h YaBl0yASQnLbH69K6dPnkMrE+3knCqo8xLxwelY6z7gaknF8V8CoYtrT6 A==; X-IronPort-AV: E=McAfee;i="6400,9594,10315"; a="261907604" X-IronPort-AV: E=Sophos;i="5.90,254,1643702400"; d="scan'208";a="261907604" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2022 11:04:55 -0700 X-IronPort-AV: E=Sophos;i="5.90,254,1643702400"; d="scan'208";a="559438893" Received: from lpfafma-mobl.amr.corp.intel.com (HELO guptapa-desk) ([10.209.17.36]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2022 11:04:54 -0700 Date: Tue, 12 Apr 2022 11:04:52 -0700 From: Pawan Gupta To: Jon Kohler Cc: Dave Hansen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "x86@kernel.org" , "H. Peter Anvin" , Tony Luck , Andi Kleen , "linux-kernel@vger.kernel.org" , Borislav Petkov , Neelima Krishnan , "kvm @ vger . kernel . org" Subject: Re: [PATCH] x86/tsx: fix KVM guest live migration for tsx=on Message-ID: <20220412180452.ityo3o3eoxh3iul7@guptapa-desk> References: <20220411180131.5054-1-jon@nutanix.com> <41a3ca80-d3e2-47d2-8f1c-9235c55de8d1@intel.com> <1767A554-CC0A-412D-B70C-12DF0AF4C690@nutanix.com> <90457491-1ac3-b04a-856a-25c6e04d429a@intel.com> <28C45B75-7FE3-4C79-9A29-F929AF9BC5A8@nutanix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <28C45B75-7FE3-4C79-9A29-F929AF9BC5A8@nutanix.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 12, 2022 at 04:08:32PM +0000, Jon Kohler wrote: > > >> On Apr 12, 2022, at 11:54 AM, Dave Hansen wrote: >> >> On 4/12/22 06:36, Jon Kohler wrote: >>> So my theory here is to extend the logical effort of the microcode driven >>> automatic disablement as well as the tsx=auto automatic disablement and >>> have tsx=on force abort all transactions on X86_BUG_TAA SKUs, but leave >>> the CPU features enumerated to maintain live migration. >>> >>> This would still leave TSX totally good on Ice Lake / non-buggy systems. >>> >>> If it would help, I'm working up an RFC patch, and we could discuss there? >> >> Sure. But, it sounds like you really want a new tdx=something rather >> than to muck with tsx=on behavior. Surely someone else will come along >> and complain that we broke their TDX setup if we change its behavior. > >Good point, there will always be a squeaky wheel. I’ll work that into the RFC, >I’ll do something like tsx=compat and see how it shapes up. FYI, the original series had tsx=fake, that would have taken care of this breakage. https://lore.kernel.org/lkml/de6b97a567e273adff1f5268998692bad548aa10.1623272033.git-series.pawan.kumar.gupta@linux.intel.com/ For the lack of real world use-cases at that time, this patch was dropped. Thanks, Pawan