Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756251Ab1CVOND (ORCPT ); Tue, 22 Mar 2011 10:13:03 -0400 Received: from mga11.intel.com ([192.55.52.93]:41649 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755240Ab1CVONB (ORCPT ); Tue, 22 Mar 2011 10:13:01 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.63,224,1299484800"; d="scan'208";a="669943437" From: Youquan Song To: linux-kernel@vger.kernel.org, hpa@linux.intel.com, david.woodhouse@intel.com Cc: suresh.b.siddha@intel.com, allen.m.kay@intel.com, kent.liu@intel.com, Youquan Song , Youquan Song Subject: [PATCH] enable x2apic opt out Date: Tue, 22 Mar 2011 22:06:47 +0800 Message-Id: <1300802807-7742-1-git-send-email-youquan.song@intel.com> X-Mailer: git-send-email 1.6.4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5350 Lines: 171 New version of VT-d2 specification includes a new feature that provide firmware a way to request system software to opt out of enable x2APIC mode. DMAR ACPI table newly define flags.1 bit: x2APIC_OPT_OUT which is set to request System software opt out xAPIC mode if flags.0 bit:INTR_REMAP is also set. This patch enable the feature. Also re-define x2apic_supported() to address platform x2apic support needs 1)processor has x2apic capability 2)interrupt remapping support 3)firmware does not request opt-out. Signed-off-by: Youquan Song --- arch/x86/include/asm/apic.h | 2 -- arch/x86/kernel/apic/apic.c | 13 +++++++++---- drivers/pci/dmar.c | 28 ++++++++++++++++++++++++++-- include/linux/dmar.h | 3 +++ include/linux/intel-iommu.h | 4 ++++ 5 files changed, 42 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index 3c89694..aa3fc82 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -192,7 +192,6 @@ static inline int x2apic_enabled(void) return 0; } -#define x2apic_supported() (cpu_has_x2apic) static inline void x2apic_force_phys(void) { x2apic_phys = 1; @@ -213,7 +212,6 @@ static inline void x2apic_force_phys(void) } #define x2apic_preenabled 0 -#define x2apic_supported() 0 #endif extern void enable_IR_x2apic(void); diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 76b96d7..6c96c45 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1449,11 +1449,11 @@ void __init enable_IR_x2apic(void) { unsigned long flags; struct IO_APIC_route_entry **ioapic_entries = NULL; - int ret, x2apic_enabled = 0; + int ret = 0, x2apic_enabled = 0; int dmar_table_init_ret; dmar_table_init_ret = dmar_table_init(); - if (dmar_table_init_ret && !x2apic_supported()) + if (dmar_table_init_ret && !cpu_has_x2apic) return; ioapic_entries = alloc_ioapic_entries(); @@ -1465,6 +1465,7 @@ void __init enable_IR_x2apic(void) ret = save_IO_APIC_setup(ioapic_entries); if (ret) { pr_info("Saving IO-APIC state failed: %d\n", ret); + ret = 0; goto out; } @@ -1491,7 +1492,8 @@ void __init enable_IR_x2apic(void) x2apic_force_phys(); } - x2apic_enabled = 1; + if (x2apic_supported()) + x2apic_enabled = 1; if (x2apic_supported() && !x2apic_mode) { x2apic_mode = 1; @@ -1514,8 +1516,11 @@ out: if (x2apic_preenabled) panic("x2apic: enabled by BIOS but kernel init failed."); - else if (cpu_has_x2apic) + else if (!ret && cpu_has_x2apic) /* IR enabling failed */ pr_info("Not enabling x2apic, Intr-remapping init failed.\n"); + else if (!x2apic_supported() && cpu_has_x2apic) + pr_info("Not enabling x2apic, firmware requests OS opt-out " + "x2apic.\n"); } #ifdef CONFIG_X86_64 diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c index 09933eb..a35dca9 100644 --- a/drivers/pci/dmar.c +++ b/drivers/pci/dmar.c @@ -705,7 +705,7 @@ int __init detect_intel_iommu(void) * is added, we will not need this any more. */ dmar = (struct acpi_table_dmar *) dmar_tbl; - if (ret && cpu_has_x2apic && dmar->flags & 0x1) + if (ret && x2apic_supported() && dmar->flags & DMAR_INTR_REMAP) printk(KERN_INFO "Queued invalidation will be enabled to support " "x2apic and Intr-remapping.\n"); @@ -1461,6 +1461,30 @@ int __init dmar_ir_support(void) dmar = (struct acpi_table_dmar *)dmar_tbl; if (!dmar) return 0; - return dmar->flags & 0x1; + return dmar->flags & DMAR_INTR_REMAP; } + +/* + * Check if the platform support x2apic + * three necessary conditions: + * a. processor support x2apic + * b. interrupt remapping support + * c. when interrupt reamapping support,bit of x2APIC_OPT_OUT at "DMAR flags" + * is not set which means firmware does not tell OS opt out x2apic + */ +int __init x2apic_supported(void) +{ + struct acpi_table_dmar *dmar; + unsigned int flags = 0; + + if (!cpu_has_x2apic) + return 0; + + dmar = (struct acpi_table_dmar *)dmar_tbl; + if (!dmar) + return 0; + flags = DMAR_INTR_REMAP | DMAR_X2APIC_OPT_OUT; + return ((dmar->flags & flags) == DMAR_INTR_REMAP); +} + IOMMU_INIT_POST(detect_intel_iommu); diff --git a/include/linux/dmar.h b/include/linux/dmar.h index 7b776d7..73c9bff 100644 --- a/include/linux/dmar.h +++ b/include/linux/dmar.h @@ -228,8 +228,11 @@ struct dmar_atsr_unit { }; extern int intel_iommu_init(void); +extern int x2apic_supported(void); + #else /* !CONFIG_DMAR: */ static inline int intel_iommu_init(void) { return -ENODEV; } +static inline int x2apic_supported(void) { return 0; } #endif /* CONFIG_DMAR */ #endif /* __DMAR_H__ */ diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index 9310c69..2d086e5 100644 --- a/include/linux/intel-iommu.h +++ b/include/linux/intel-iommu.h @@ -29,6 +29,10 @@ #include #include +/* DMAR Flags bits */ +#define DMAR_INTR_REMAP 0x1 +#define DMAR_X2APIC_OPT_OUT 0x2 + /* * Intel IOMMU register specification per version 1.0 public spec. */ -- 1.6.4.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/