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 0F59EC25B0C for ; Sat, 6 Aug 2022 19:01:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232228AbiHFTA7 (ORCPT ); Sat, 6 Aug 2022 15:00:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41118 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229639AbiHFTAz (ORCPT ); Sat, 6 Aug 2022 15:00:55 -0400 Received: from mail-ej1-x635.google.com (mail-ej1-x635.google.com [IPv6:2a00:1450:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C224F1055F; Sat, 6 Aug 2022 12:00:54 -0700 (PDT) Received: by mail-ej1-x635.google.com with SMTP id w19so10136781ejc.7; Sat, 06 Aug 2022 12:00:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=b1/dM4HS7a7aBwHPuKKyvIe9nueiJMG06ztCYduLU7Q=; b=iVF8V9jkIU0HdsUq7ADGgunKp4UJXXkuAydwuNxdO3LzQh18BrX9DTg6aimpbfOvDY A656IAU46sJEY+x81pz22oAzbClTxqCdG+xr3XvQKpsJsaT4Wr7F9jxm5ufeLHUSo2ZK vI18kKY8GRVuxCB/9VtA8JGi7ucbCitF55QlAi+kOzLNr/6JgZZNBhuAIK2fCT4V5M5l aRP6A2rEQ2dlcP66s3PtzLN/sGvmYrUuUzYMHCVJUloyf0OF7tPYLVZoQ8PHqvSHqeqs pX+Qvo6xz4vm0QhkXMrXwymTfHD09CuFmJkQB7+w3uH2OaVaTj5pKYPQyXBGgNVFQPnc f1yg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=b1/dM4HS7a7aBwHPuKKyvIe9nueiJMG06ztCYduLU7Q=; b=oZbFw98SSrcZxYk1LnHvY8AtxUykpws0aZWaQOYjACeIHsdRnuGP8Z7o0vYF0gfuAw e4mu3ai7ZvX5//9uWdoTw+o7TBVl81kZdsWA3JQnSkHLLnjKJ/KJDX8ghTsz7OPPzKpu uRidjrOhGn5T952ykJnRKEqMtSKfMvkmcUj+k12Ib3qHegCIGnph3XNLRCcEkWJ0rFi7 qNg6UAVfSNUzagP+ApbV1zOWHt6Cro50+URUsJz4AgbddE7t29DIGwJ9MbnV/ASCugCZ 1PiA7VgjnYmcpuLHffQtVkMT2nDomnhxLwXTvcNdhti7flzxwPPyzrlNipFTrJgGG1B1 Slcg== X-Gm-Message-State: ACgBeo1/GHrVy/vZnlxhoki+UW4Wpuv1RnYhk1djsxUzwcUOjG4pDsw3 1cGlpv90ABaep91J95K+Hvk= X-Google-Smtp-Source: AA6agR5KFJntmnEbjbxvWA7jSR4+1TjQ4fFm1CTW5tqU8qCCzdekE8xaMos/mHD2uqSlSOgjCez3Rg== X-Received: by 2002:a17:907:75e7:b0:730:9711:ad80 with SMTP id jz7-20020a17090775e700b007309711ad80mr8826974ejc.35.1659812453249; Sat, 06 Aug 2022 12:00:53 -0700 (PDT) Received: from gmail.com (195-38-112-141.pool.digikabel.hu. [195.38.112.141]) by smtp.gmail.com with ESMTPSA id l2-20020a1709061c4200b00730538b7cf1sm2984909ejg.75.2022.08.06.12.00.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 06 Aug 2022 12:00:52 -0700 (PDT) Sender: Ingo Molnar Date: Sat, 6 Aug 2022 21:00:50 +0200 From: Ingo Molnar To: Kim Phillips Cc: bp@alien8.de, x86@kernel.org, peterz@infradead.org, bp@suse.de, bpf@vger.kernel.org, jpoimboe@redhat.com, andrew.cooper3@citrix.com, linux-kernel@vger.kernel.org, thomas.lendacky@amd.com Subject: Re: [PATCH v2] x86/bugs: Enable STIBP for IBPB mitigated RetBleed Message-ID: References: <20220805215009.498407-1-kim.phillips@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220805215009.498407-1-kim.phillips@amd.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Kim Phillips wrote: > Speculative Code Execution with Return Instructions) > vulnerability. > > + AMD-based unret and ibpb mitigations alone do not stop > + sibling threads influencing the predictions of other sibling > + threads. For that reason, we use STIBP on processors > + that support it, and mitigate SMT on processors that don't. > * retbleed_select_mitigation(); specifically the STIBP selection is > - * forced for UNRET. > + * forced for UNRET or IBPB. Nit: could you please capitalize the acronyms & instruction names consistently? Human eyesight is case sensitive. Ie. it should be UNRET and IBPB everywhere. Thanks, Ingo