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x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfI2oRxuyzjQUETAWkVrTr/HVIIZ2+vg7kWxvukoXWzinZLnV+tUMsi7sMueFeBTWdvaUDGk7HAzbqC3ITGNdMo0PEbR+mMoOVMzuS4yKbtyiUQ1x96Sm aULnS74+g1rU1u3XuhTgIpqqDvkzbnySuPK6guHfL1B2BvgUtvZYCpAnzkSZ486rOAN5m2ca1z7hXhxeal3xtyNA/VtZw2r9uGnyOqtJEkDJxO4YW51bo1Am X-CM-Analysis: v=2.3 cv=JLoVTfCb c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=IkcTkHD0fZMA:10 a=VUJBJC2UJ8kA:10 a=yPCof4ZbAAAA:8 a=VwQbUJbxAAAA:8 a=pBOR-ozoAAAA:8 a=ag1SF4gXAAAA:8 a=63lcS0CwuErnrpi3ut4A:9 a=QEXdDO2ut3YA:10 a=AjGcO6oz07-iQ99wixmX:22 a=Yupwre4RP9_Eg_Bd0iYG:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751176AbeEUVPr (ORCPT ); Mon, 21 May 2018 17:15:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:59134 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751368AbeEUVPm (ORCPT ); Mon, 21 May 2018 17:15:42 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Konrad Rzeszutek Wilk , Thomas Gleixner , Ingo Molnar , David Woodhouse Subject: [PATCH 4.9 45/87] x86/bugs: Whitelist allowed SPEC_CTRL MSR values Date: Mon, 21 May 2018 23:11:21 +0200 Message-Id: <20180521210424.608193168@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180521210420.222671977@linuxfoundation.org> References: <20180521210420.222671977@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Konrad Rzeszutek Wilk commit 1115a859f33276fe8afb31c60cf9d8e657872558 upstream Intel and AMD SPEC_CTRL (0x48) MSR semantics may differ in the future (or in fact use different MSRs for the same functionality). As such a run-time mechanism is required to whitelist the appropriate MSR values. [ tglx: Made the variable __ro_after_init ] Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/bugs.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -34,6 +34,12 @@ static void __init ssb_select_mitigation */ static u64 __ro_after_init x86_spec_ctrl_base; +/* + * The vendor and possibly platform specific bits which can be modified in + * x86_spec_ctrl_base. + */ +static u64 __ro_after_init x86_spec_ctrl_mask = ~SPEC_CTRL_IBRS; + void __init check_bugs(void) { identify_boot_cpu(); @@ -116,7 +122,7 @@ static enum spectre_v2_mitigation spectr void x86_spec_ctrl_set(u64 val) { - if (val & ~(SPEC_CTRL_IBRS | SPEC_CTRL_RDS)) + if (val & x86_spec_ctrl_mask) WARN_ONCE(1, "SPEC_CTRL MSR value 0x%16llx is unknown.\n", val); else wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base | val); @@ -458,6 +464,7 @@ static enum ssb_mitigation_cmd __init __ switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_INTEL: x86_spec_ctrl_base |= SPEC_CTRL_RDS; + x86_spec_ctrl_mask &= ~SPEC_CTRL_RDS; x86_spec_ctrl_set(SPEC_CTRL_RDS); break; case X86_VENDOR_AMD: @@ -481,7 +488,7 @@ static void ssb_select_mitigation() void x86_spec_ctrl_setup_ap(void) { if (boot_cpu_has(X86_FEATURE_IBRS)) - x86_spec_ctrl_set(x86_spec_ctrl_base & (SPEC_CTRL_IBRS | SPEC_CTRL_RDS)); + x86_spec_ctrl_set(x86_spec_ctrl_base & ~x86_spec_ctrl_mask); } #ifdef CONFIG_SYSFS