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 X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_PASS,USER_AGENT_NEOMUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E842C4360F for ; Fri, 5 Apr 2019 14:31:23 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id D2B93206DD for ; Fri, 5 Apr 2019 14:31:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="rXoIUSre" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D2B93206DD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject: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=1lH8hSsyH/fo5VvjG3D7xGfZHGNNxz+Flh89f8y+00I=; b=rXoIUSrezBu0zs ZfQmSQaqSpAhUC1O26kKFaEJqAfHr81b/IyKhENt8+orCTRN43Lmr1ZlMUTiOUJremh4oIPjqUyFY D3mxZ4C2T5flemk9zxluLXCvvbwMwGj1kq9eegppTdQ6pzqnXGiGpUE7fXgFvztPMT/+G3OJBZe5q L3brVxtnIwHUvnC6fhU2kVmCzKLylGy/d2HjPCWph+iMaVKfrEVTIvoQd9a++wh23CbB3zAIbIseH BHLERNF40dGY3kz5L0RLbZbcxXvmo2/d2+BL28P1dQCKKFQLSmrjFH8Tb624XmlcubQm0cYVdlB71 pFlXcznbMi+wv/2GIdDA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hCPsD-0004ui-58; Fri, 05 Apr 2019 14:31:17 +0000 Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hCPsA-0004ts-04 for linux-arm-kernel@lists.infradead.org; Fri, 05 Apr 2019 14:31:15 +0000 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E645E308FF30; Fri, 5 Apr 2019 14:31:12 +0000 (UTC) Received: from treble (ovpn-123-87.rdu2.redhat.com [10.10.123.87]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AFB2F60C7A; Fri, 5 Apr 2019 14:31:03 +0000 (UTC) Date: Fri, 5 Apr 2019 09:31:01 -0500 From: Josh Poimboeuf To: Borislav Petkov Subject: Re: [PATCH RFC 2/5] x86/speculation: Add support for 'cpu_spec_mitigations=' cmdline options Message-ID: <20190405143101.ksj7ayjis4p52dgt@treble> References: <78c63cb08f36f55407f534d49cc2543079e44dbb.1554396090.git.jpoimboe@redhat.com> <20190405135712.GF23348@zn.tnic> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190405135712.GF23348@zn.tnic> User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Fri, 05 Apr 2019 14:31:13 +0000 (UTC) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190405_073114_079662_BEDEA66E X-CRM114-Status: GOOD ( 21.72 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Zijlstra , Benjamin Herrenschmidt , Heiko Carstens , Paul Mackerras , "H . Peter Anvin" , Ingo Molnar , Andrea Arcangeli , linux-s390@vger.kernel.org, Michael Ellerman , x86@kernel.org, Will Deacon , Linus Torvalds , Catalin Marinas , Waiman Long , linux-arch@vger.kernel.org, Jon Masters , Jiri Kosina , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Tyler Hicks , Martin Schwidefsky , linuxppc-dev@lists.ozlabs.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Apr 05, 2019 at 03:57:12PM +0200, Borislav Petkov wrote: > > diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h > > index 2bb3a648fc12..7e95b310f869 100644 > > --- a/arch/x86/include/asm/processor.h > > +++ b/arch/x86/include/asm/processor.h > > @@ -982,6 +982,7 @@ void microcode_check(void); > > > > enum l1tf_mitigations { > > L1TF_MITIGATION_OFF, > > + L1TF_MITIGATION_DEFAULT, > > L1TF_MITIGATION_FLUSH_NOWARN, > > L1TF_MITIGATION_FLUSH, > > L1TF_MITIGATION_FLUSH_NOSMT, > > diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c > > index 2da82eff0eb4..65b95fb95ba5 100644 > > --- a/arch/x86/kernel/cpu/bugs.c > > +++ b/arch/x86/kernel/cpu/bugs.c > > @@ -308,8 +308,11 @@ spectre_v2_parse_user_cmdline(enum spectre_v2_mitigation_cmd v2_cmd) > > > > ret = cmdline_find_option(boot_command_line, "spectre_v2_user", > > arg, sizeof(arg)); > > - if (ret < 0) > > + if (ret < 0) { > > + if (cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) > > + return SPECTRE_V2_USER_CMD_NONE; > > Instead of sprinkling that test in those three functions, just do it > once above in check_bugs(), before those *_select_mitigation() functions > get to run and depending on the value, you either run them or use the > default settings, for the OFF case, for example. My thinking was that the individual options could be used to override the global option. But maybe that's overkill? I dunno. > > return SPECTRE_V2_USER_CMD_AUTO; > > + } > > > > for (i = 0; i < ARRAY_SIZE(v2_user_options); i++) { > > if (match_option(arg, ret, v2_user_options[i].option)) { > > @@ -444,8 +447,11 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void) > > return SPECTRE_V2_CMD_NONE; > > > > ret = cmdline_find_option(boot_command_line, "spectre_v2", arg, sizeof(arg)); > > - if (ret < 0) > > + if (ret < 0) { > > + if (cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) > > + return SPECTRE_V2_CMD_NONE; > > return SPECTRE_V2_CMD_AUTO; > > + } > > > > for (i = 0; i < ARRAY_SIZE(mitigation_options); i++) { > > if (!match_option(arg, ret, mitigation_options[i].option)) > > @@ -677,8 +683,11 @@ static enum ssb_mitigation_cmd __init ssb_parse_cmdline(void) > > } else { > > ret = cmdline_find_option(boot_command_line, "spec_store_bypass_disable", > > arg, sizeof(arg)); > > - if (ret < 0) > > + if (ret < 0) { > > + if (cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) > > + return SPEC_STORE_BYPASS_CMD_NONE; > > return SPEC_STORE_BYPASS_CMD_AUTO; > > + } > > > > for (i = 0; i < ARRAY_SIZE(ssb_mitigation_options); i++) { > > if (!match_option(arg, ret, ssb_mitigation_options[i].option)) > > @@ -955,7 +964,7 @@ void x86_spec_ctrl_setup_ap(void) > > #define pr_fmt(fmt) "L1TF: " fmt > > > > /* Default mitigation for L1TF-affected CPUs */ > > -enum l1tf_mitigations l1tf_mitigation __ro_after_init = L1TF_MITIGATION_FLUSH; > > +enum l1tf_mitigations l1tf_mitigation __ro_after_init = L1TF_MITIGATION_DEFAULT; > > #if IS_ENABLED(CONFIG_KVM_INTEL) > > EXPORT_SYMBOL_GPL(l1tf_mitigation); > > #endif > > @@ -1010,8 +1019,23 @@ static void __init l1tf_select_mitigation(void) > > > > override_cache_bits(&boot_cpu_data); > > > > + if (l1tf_mitigation == L1TF_MITIGATION_DEFAULT) { > > + switch (cpu_spec_mitigations) { > > + case CPU_SPEC_MITIGATIONS_OFF: > > + l1tf_mitigation = L1TF_MITIGATION_OFF; > > + break; > > + case CPU_SPEC_MITIGATIONS_AUTO: > > + l1tf_mitigation = L1TF_MITIGATION_FLUSH; > > + break; > > + case CPU_SPEC_MITIGATIONS_AUTO_NOSMT: > > + l1tf_mitigation = L1TF_MITIGATION_FLUSH_NOSMT; > > + break; > > + } > > + } > > + > > switch (l1tf_mitigation) { > > case L1TF_MITIGATION_OFF: > > + case L1TF_MITIGATION_DEFAULT: > > case L1TF_MITIGATION_FLUSH_NOWARN: > > case L1TF_MITIGATION_FLUSH: > > break; > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > > index ab432a930ae8..83b5bdc3c777 100644 > > --- a/arch/x86/kvm/vmx/vmx.c > > +++ b/arch/x86/kvm/vmx/vmx.c > > @@ -233,6 +233,7 @@ static int vmx_setup_l1d_flush(enum vmx_l1d_flush_state l1tf) > > case L1TF_MITIGATION_FLUSH_NOWARN: > > case L1TF_MITIGATION_FLUSH: > > case L1TF_MITIGATION_FLUSH_NOSMT: > > + case L1TF_MITIGATION_DEFAULT: > > l1tf = VMENTER_L1D_FLUSH_COND; > > break; > > case L1TF_MITIGATION_FULL: > > @@ -6686,6 +6687,7 @@ static int vmx_vm_init(struct kvm *kvm) > > case L1TF_MITIGATION_FLUSH: > > case L1TF_MITIGATION_FLUSH_NOSMT: > > case L1TF_MITIGATION_FULL: > > + case L1TF_MITIGATION_DEFAULT: > > /* > > * Warn upon starting the first VM in a potentially > > * insecure environment. > > The L1TF bits need to be a separate patch. I assume you mean just the part where L1TF_MITIGATION_DEFAULT is added? -- Josh _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel