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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 121BCC54EBD for ; Thu, 12 Jan 2023 10:34:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=tUjiI3FhG/dUpQcSYIvHWMUhSwhT89Vrc6Z4nQjx5n4=; b=3eCHtklfCutMuS WcJJcBXn8lWGHZhx1+wweD0WmkpnzkA4VMbWtTRQHlqAfjP/HSx/y7yLfidbvYF35WvKT3RV6NuhX bv2XkkyZnN4Qr5x1aJ06LIvXWGjyPbnuROB264+1qimgFDjTYt2klVLohVgRIrEzFcUviZTrtcQ9K EcgdQLCWzsBQkI753SnfHP1D1YkZ7TKSeKzX5+syRPMP6HTW50SMXtlsH7/9afWaiJQSMTc466A46 vkOz0jNUCXndDVkC/Y9M/IHSJbGDNhVEDF3NdzL89dxRn2bl/OP50raX8OdKxmOOBm7o4kZWR/qkh xnsJYM/u174jrn+hF+dw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pFuun-00EbTF-Oe; Thu, 12 Jan 2023 10:34:33 +0000 Received: from mail.skyhub.de ([2a01:4f8:190:11c2::b:1457]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pFuuf-00EbOP-PW for kexec@lists.infradead.org; Thu, 12 Jan 2023 10:34:27 +0000 Received: from zn.tnic (p5de8e9fe.dip0.t-ipconnect.de [93.232.233.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 824171EC04A9; Thu, 12 Jan 2023 11:34:14 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1673519654; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=CJ1uL2ZqSBbV653T/Ui6KWFShGRfcaqwoq4TgOsz5Q0=; b=PciC4Qa5czY4g5t8Yzc7JIAhA6koQP0Ox6MVVEXSKlsBLa8JSZmEb/nmDHtJpIZSynNnfR TxGIJuX14Rz6hmdaXwSy9qWrKlCVjGbSsY9bWR0N18MdQddWRJtPvXclfvh7dPkz3Oa8JB D9qiK40XVjjAhDtmWAbkS7t9AvtbAk8= Date: Thu, 12 Jan 2023 11:34:08 +0100 From: Borislav Petkov To: Pawan Gupta Cc: Breno Leitao , tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, jpoimboe@kernel.org, peterz@infradead.org, x86@kernel.org, cascardo@canonical.com, leit@meta.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] x86/bugs: Explicitly clear speculative MSR bits Message-ID: References: <20221128153148.1129350-1-leitao@debian.org> <20230112070037.q6cg23tn57onmxfi@desk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230112070037.q6cg23tn57onmxfi@desk> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230112_023426_011552_E9189BFE X-CRM114-Status: GOOD ( 12.03 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On Wed, Jan 11, 2023 at 11:00:37PM -0800, Pawan Gupta wrote: > > SPEC_CTRL_RRSBA_DIS_S is a disable bit and I presume it needs to stay enabled. > > The mitigation is enabled when this bit is set. When set, it prevents RET > target to be predicted from alternate predictors (BTB). This should stay > 0, unless enabled by a mitigation mode. > > > Only when spec_ctrl_disable_kernel_rrsba() runs. And I'd say perf-wise it > > doesn't cost that much... > > I guess this doesn't matter now, because this patch is resetting it by > default that keeps the mitigation disabled with no perf impact. Ok, lemme queue it then. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec