From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:60468 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754794AbdK1KmZ (ORCPT ); Tue, 28 Nov 2017 05:42:25 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tomeu Vizoso , Tom Lendacky , Thomas Gleixner , Peter Zijlstra , Borislav Petkov , regression@leemhuis.info Subject: [PATCH 4.14 013/193] x86/boot: Fix boot failure when SMP MP-table is based at 0 Date: Tue, 28 Nov 2017 11:24:20 +0100 Message-Id: <20171128100614.210728626@linuxfoundation.org> In-Reply-To: <20171128100613.638270407@linuxfoundation.org> References: <20171128100613.638270407@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tom Lendacky commit ac5292e9a294618cecb31109d1ba265e3d027ba2 upstream. When crosvm is used to boot a kernel as a VM, the SMP MP-table is found at physical address 0x0. This causes mpf_base to be set to 0 and a subsequent "if (!mpf_base)" check in default_get_smp_config() results in the MP-table not being parsed. Further into the boot this results in an oops when attempting a read_apic_id(). Add a boolean variable that is set to true when the MP-table is found. Use this variable for testing if the MP-table was found so that even a value of 0 for mpf_base will result in continued parsing of the MP-table. Fixes: 5997efb96756 ("x86/boot: Use memremap() to map the MPF and MPC data") Reported-by: Tomeu Vizoso Signed-off-by: Tom Lendacky Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: Borislav Petkov Cc: regression@leemhuis.info Link: https://lkml.kernel.org/r/20171106201753.23059.86674.stgit@tlendack-t1.amdoffice.net Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/mpparse.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/mpparse.c +++ b/arch/x86/kernel/mpparse.c @@ -431,6 +431,7 @@ static inline void __init construct_defa } static unsigned long mpf_base; +static bool mpf_found; static unsigned long __init get_mpc_size(unsigned long physptr) { @@ -504,7 +505,7 @@ void __init default_get_smp_config(unsig if (!smp_found_config) return; - if (!mpf_base) + if (!mpf_found) return; if (acpi_lapic && early) @@ -593,6 +594,7 @@ static int __init smp_scan_config(unsign smp_found_config = 1; #endif mpf_base = base; + mpf_found = true; pr_info("found SMP MP-table at [mem %#010lx-%#010lx] mapped at [%p]\n", base, base + sizeof(*mpf) - 1, mpf); @@ -858,7 +860,7 @@ static int __init update_mp_table(void) if (!enable_update_mptable) return 0; - if (!mpf_base) + if (!mpf_found) return 0; mpf = early_memremap(mpf_base, sizeof(*mpf));