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From: Jiang Liu <jiang.liu@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Joerg Roedel <joro@8bytes.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Yinghai Lu <yinghai@kernel.org>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, Jiang Liu <jiang.liu@linux.intel.com>,
	David Rientjes <rientjes@google.com>,
	HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>,
	Jan Beulich <JBeulich@suse.com>,
	Richard Weinberger <richard@nod.at>,
	Oren Twaig <oren@scalemp.com>
Cc: Tony Luck <tony.luck@intel.com>,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	"H. Peter Anvin" <hpa@linux.intel.com>,
	Ingo Molnar <mingo@kernel.org>
Subject: [Patch v2 07/16] x86/apic: Refine enable_IR_x2apic() and related functions
Date: Wed,  7 Jan 2015 15:31:34 +0800
Message-ID: <1420615903-28253-8-git-send-email-jiang.liu@linux.intel.com> (raw)
In-Reply-To: <1420615903-28253-1-git-send-email-jiang.liu@linux.intel.com>

Refine enable_IR_x2apic() and related functions for better readability.

It also changes the way to handle IR in XAPIC mode when enabling X2APIC.
Previously it just skips X2APIC initialization without checking max CPU
APIC ID in system, which may cause problem if system has CPU with APIC
ID bigger than 255. So treat IR in XAPIC mode as same as IR is disabled
when enabling CPU X2APIC.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
 arch/x86/kernel/apic/apic.c |   85 +++++++++++++++++++++----------------------
 1 file changed, 41 insertions(+), 44 deletions(-)

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 8ce2b8236c1b..09ac1e4ef86b 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1572,7 +1572,7 @@ void enable_x2apic(void)
 }
 #endif /* CONFIG_X86_X2APIC */
 
-int __init enable_IR(void)
+static int __init try_to_enable_IR(void)
 {
 #ifdef CONFIG_IRQ_REMAP
 	if (!irq_remapping_supported()) {
@@ -1585,17 +1585,48 @@ int __init enable_IR(void)
 			"io-apic setup\n");
 		return -1;
 	}
+#endif
 
 	return irq_remapping_enable();
+}
+
+static __init void try_to_enable_x2apic(int ir_stat)
+{
+#ifdef CONFIG_X86_X2APIC
+	if (!x2apic_supported())
+		return;
+
+	if (ir_stat != IRQ_REMAP_X2APIC_MODE) {
+		/* IR is required if there is APIC ID > 255 even when running
+		 * under KVM
+		 */
+		if (max_physical_apicid > 255 ||
+		    !hypervisor_x2apic_available()) {
+			pr_info("IRQ remapping doesn't support X2APIC mode, disable x2apic.\n");
+			if (x2apic_preenabled)
+				disable_x2apic();
+			return;
+		}
+
+		/*
+		 * without IR all CPUs can be addressed by IOAPIC/MSI
+		 * only in physical mode
+		 */
+		x2apic_force_phys();
+	}
+
+	if (!x2apic_mode) {
+		x2apic_mode = 1;
+		enable_x2apic();
+		pr_info("Enabled x2apic\n");
+	}
 #endif
-	return -1;
 }
 
 void __init enable_IR_x2apic(void)
 {
 	unsigned long flags;
-	int ret;
-	int hardware_init_ret;
+	int ret, ir_stat;
 
 	if (!IS_ENABLED(CONFIG_X86_X2APIC)) {
 		u64 msr;
@@ -1605,8 +1636,8 @@ void __init enable_IR_x2apic(void)
 			panic("BIOS has enabled x2apic but kernel doesn't support x2apic, please disable x2apic in BIOS.\n");
 	}
 
-	hardware_init_ret = irq_remapping_prepare();
-	if (hardware_init_ret && !x2apic_supported())
+	ir_stat = irq_remapping_prepare();
+	if (ir_stat < 0 && !x2apic_supported())
 		return;
 
 	ret = save_ioapic_entries();
@@ -1621,45 +1652,11 @@ void __init enable_IR_x2apic(void)
 
 	if (x2apic_preenabled && nox2apic)
 		disable_x2apic();
+	if (ir_stat >= 0)
+		ir_stat = try_to_enable_IR();
+	try_to_enable_x2apic(ir_stat);
 
-	if (hardware_init_ret)
-		ret = -1;
-	else
-		ret = enable_IR();
-
-	if (!x2apic_supported())
-		goto skip_x2apic;
-
-	if (ret < 0) {
-		/* IR is required if there is APIC ID > 255 even when running
-		 * under KVM
-		 */
-		if (max_physical_apicid > 255 ||
-		    !hypervisor_x2apic_available()) {
-			if (x2apic_preenabled)
-				disable_x2apic();
-			goto skip_x2apic;
-		}
-		/*
-		 * without IR all CPUs can be addressed by IOAPIC/MSI
-		 * only in physical mode
-		 */
-		x2apic_force_phys();
-	}
-
-	if (ret == IRQ_REMAP_XAPIC_MODE) {
-		pr_info("x2apic not enabled, IRQ remapping is in xapic mode\n");
-		goto skip_x2apic;
-	}
-
-	if (x2apic_supported() && !x2apic_mode) {
-		x2apic_mode = 1;
-		enable_x2apic();
-		pr_info("Enabled x2apic\n");
-	}
-
-skip_x2apic:
-	if (ret < 0) /* IR enabling failed */
+	if (ir_stat < 0) /* IR enabling failed */
 		restore_ioapic_entries();
 	legacy_pic->restore_mask();
 	local_irq_restore(flags);
-- 
1.7.10.4


  parent reply index

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-07  7:31 [Patch v2 00/16] Refine IR initialization flow and fixes bugs related to X2APIC Jiang Liu
2015-01-07  7:31 ` [Patch v2 01/16] iommu, x86: Restructure setup of the irq remapping feature Jiang Liu
2015-01-15 12:58   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2015-01-07  7:31 ` [Patch v2 02/16] iommu/vt-d: Move iommu preparatory allocations to irq_remap_ops.prepare Jiang Liu
2015-01-15 12:58   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2015-01-07  7:31 ` [Patch v2 03/16] iommu/vt-d: Convert allocations to GFP_KERNEL Jiang Liu
2015-01-15 12:59   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2015-01-07  7:31 ` [Patch v2 04/16] x86/apic: Panic if kernel doesn't support x2apic but BIOS has enabled x2apic Jiang Liu
2015-01-15 12:59   ` [tip:x86/apic] x86/apic: Panic if kernel doesn' t " tip-bot for Jiang Liu
2015-01-07  7:31 ` [Patch v2 05/16] x86/apic: Kill useless variable x2apic_enabled in function enable_IR_x2apic() Jiang Liu
2015-01-15 12:59   ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07  7:31 ` [Patch v2 06/16] x86/apic: Correctly detect X2APIC status in function enable_IR() Jiang Liu
2015-01-15 13:00   ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07  7:31 ` Jiang Liu [this message]
2015-01-15  9:24   ` [Patch v2 07/16] x86/apic: Refine enable_IR_x2apic() and related functions Thomas Gleixner
2015-01-15 13:00   ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-15 13:00   ` [tip:x86/apic] x86/apic: Handle XAPIC remap mode proper tip-bot for Jiang Liu
2015-01-07  7:31 ` [Patch v2 08/16] iommu/vt-d: Prepare for killing function irq_remapping_supported() Jiang Liu
2015-01-15 13:01   ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07  7:31 ` [Patch v2 09/16] iommu/vt-d: Allocate IRQ remapping data structures only for all IOMMUs Jiang Liu
2015-01-15 13:01   ` [tip:x86/apic] " tip-bot for Joerg Roedel
2015-01-07  7:31 ` [Patch v2 10/16] iommu/vt-d: Allow IR works in XAPIC mode though CPU works in X2APIC mode Jiang Liu
2015-01-15 13:01   ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07  7:31 ` [Patch v2 11/16] x86/apic: Only disable CPU x2apic mode when necessary Jiang Liu
2015-01-15 13:02   ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07  7:31 ` [Patch v2 12/16] iommu/amd: Check for irq-remap support amd_iommu_prepare() Jiang Liu
2015-01-15 13:02   ` [tip:x86/apic] " tip-bot for Joerg Roedel
2015-01-07  7:31 ` [Patch v2 13/16] iommu/irq_remapping: Kill function irq_remapping_supported() and related code Jiang Liu
2015-01-15 13:02   ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07  7:31 ` [Patch v2 14/16] iommu/irq_remapping: Refine function irq_remapping_prepare() for maintenance Jiang Liu
2015-01-15 13:03   ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07  7:31 ` [Patch v2 15/16] iommu/irq_remapping: Change variable disable_irq_remap to be static Jiang Liu
2015-01-15 13:03   ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07  7:31 ` [Patch v2 16/16] iommu/irq_remapping: Normailize the way to detect whether IR is enabled Jiang Liu
2015-01-15 13:03   ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-09 12:03 ` [Patch v2 00/16] Refine IR initialization flow and fixes bugs related to X2APIC Joerg Roedel
  -- strict thread matches above, loose matches on Subject: below --
2014-12-05  8:48 [patch 0/5] x86/iommu: Bootup stage cleanups Thomas Gleixner
2014-12-05  8:48 ` [patch 1/5] x86, smpboot: Remove pointless preempt_disable() in native_smp_prepare_cpus() Thomas Gleixner
2014-12-05 23:25   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2014-12-19 14:02   ` tip-bot for Thomas Gleixner
2014-12-05  8:48 ` [patch 2/5] iommu, x86: Restructure setup of the irq remapping feature Thomas Gleixner
2014-12-05 23:25   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2014-12-05  8:48 ` [patch 3/5] iommu/vt-d: Move iommu preparatory allocations to irq_remap_ops.prepare Thomas Gleixner
2014-12-05 23:26   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2014-12-11  7:35     ` Yinghai Lu
2014-12-11 14:33       ` Jiang Liu
2014-12-11 17:57         ` Yinghai Lu
2014-12-11 20:30           ` Thomas Gleixner
2014-12-12  2:04             ` Yinghai Lu
2015-04-27 22:46               ` Yinghai Lu
2015-04-29  8:15                 ` Jiang Liu
2014-12-05  8:48 ` [patch 4/5] irqdomain: Revert gfp hackery Thomas Gleixner
2014-12-05 23:26   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2014-12-05  8:48 ` [patch 5/5] iommu/vt-d: Convert allocations to GFP_KERNEL Thomas Gleixner
2014-12-05 23:26   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2014-12-05 12:22 ` [patch 0/5] x86/iommu: Bootup stage cleanups Joerg Roedel

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