From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752124AbaLQEdx (ORCPT ); Tue, 16 Dec 2014 23:33:53 -0500 Received: from mga01.intel.com ([192.55.52.88]:36957 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751267AbaLQEdv (ORCPT ); Tue, 16 Dec 2014 23:33:51 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,862,1389772800"; d="scan'208";a="429971429" From: Jiang Liu To: Thomas Gleixner , Joerg Roedel , Benjamin Herrenschmidt , Ingo Molnar , "H. Peter Anvin" , Yinghai Lu , Borislav Petkov , x86@kernel.org, Jiang Liu , David Rientjes , HATAYAMA Daisuke , Richard Weinberger , Oren Twaig Cc: Tony Luck , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, "H. Peter Anvin" , Ingo Molnar Subject: [Patch v1 12/17] x86/apic: Only disable CPU x2apic mode when necessary Date: Wed, 17 Dec 2014 12:35:43 +0800 Message-Id: <1418790948-22804-13-git-send-email-jiang.liu@linux.intel.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1418790948-22804-1-git-send-email-jiang.liu@linux.intel.com> References: <1418790948-22804-1-git-send-email-jiang.liu@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When interrupt remapping hardware is not in X2APIC, CPU X2APIC mode will be disabled if: 1) Maximum CPU APIC ID is bigger than 255 2) hypervisior doesn't support x2apic mode. But we should only check whether hypervisor supports X2APIC mode when hypervisor(CONFIG_HYPERVISOR_GUEST) is enabled, otherwise X2APIC will always be disabled when CONFIG_HYPERVISOR_GUEST is disabled and IR doesn't work in X2APIC mode. Signed-off-by: Jiang Liu --- arch/x86/kernel/apic/apic.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index c6204eab3d1b..95ed9e7e7548 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1601,7 +1601,8 @@ static __init void try_to_enable_x2apic(int ir_stat) * under KVM */ if (max_physical_apicid > 255 || - !hypervisor_x2apic_available()) { + (IS_ENABLED(CONFIG_HYPERVISOR_GUEST) && + !hypervisor_x2apic_available())) { pr_info("IRQ remapping doesn't support X2APIC mode, disable x2apic.\n"); if (x2apic_preenabled) disable_x2apic(); -- 1.7.10.4