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From: tip-bot for Thomas Gleixner <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: tglx@linutronix.de, jiang.liu@linux.intel.com,
	tony.luck@intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org,
	yinghai@kernel.org, bp@alien8.de, mingo@kernel.org,
	benh@kernel.crashing.org, joro@8bytes.org
Subject: [tip:x86/apic] iommu/vt-d: Move iommu preparatory allocations to irq_remap_ops.prepare
Date: Thu, 15 Jan 2015 04:58:42 -0800
Message-ID: <tip-11190302400dc5825e429e79dda30d59c2d9525a@git.kernel.org> (raw)
In-Reply-To: <1420615903-28253-3-git-send-email-jiang.liu@linux.intel.com>

Commit-ID:  11190302400dc5825e429e79dda30d59c2d9525a
Gitweb:     http://git.kernel.org/tip/11190302400dc5825e429e79dda30d59c2d9525a
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Wed, 7 Jan 2015 15:31:29 +0800
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 15 Jan 2015 11:24:22 +0100

iommu/vt-d: Move iommu preparatory allocations to irq_remap_ops.prepare

The whole iommu setup for irq remapping is a convoluted mess. The
iommu detect function gets called from mem_init() and the prepare
callback gets called from enable_IR_x2apic() for unknown reasons.

Of course AMD and Intel setup differs in nonsensical ways. Intels
prepare callback is explicit while AMDs prepare callback is implicit
in setup_irq_remapping_ops() just to be called in the prepare call
again.

Because all of this gets called from enable_IR_x2apic() and the dmar
prepare function merily parses the ACPI tables, but does not allocate
memory we end up with memory allocation from irq disabled context
later on.

AMDs iommu code at least allocates the required memory from the
prepare function. That has issues as well, but thats not scope of this
patch.

The goal of this change is to distangle the allocation from the actual
enablement. There is no point to allocate memory from irq disabled
regions with GFP_ATOMIC just because it does not matter at that point
in the boot stage. It matters with physical hotplug later on.

There is another issue with the current setup. Due to the conversion
to stacked irqdomains we end up with a call into the irqdomain
allocation code from irq disabled context, but that code does
GFP_KERNEL allocations rightfully as there is no reason to do
preperatory allocations with GFP_ATOMIC.

That change caused the allocator code to complain about GFP_KERNEL
allocations invoked in atomic context. Boris provided a temporary
hackaround which changed the GFP flags if irq_domain_add() got called
from atomic context. Not pretty and we really dont want to get this
into a mainline release for obvious reasons.

Move the ACPI table parsing and the resulting memory allocations from
the enable to the prepare function. That allows to get rid of the
horrible hackaround in irq_domain_add() later.

[Jiang] Rebased onto v3.19

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Acked-and-tested-by: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20141205084147.313026156@linutronix.de
Link: http://lkml.kernel.org/r/1420615903-28253-3-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 drivers/iommu/intel_irq_remapping.c | 64 +++++++++++++++++++++++++------------
 1 file changed, 44 insertions(+), 20 deletions(-)

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index a55b207..2360cb6 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -595,22 +595,57 @@ static int __init intel_irq_remapping_supported(void)
 	return 1;
 }
 
-static int __init intel_enable_irq_remapping(void)
+static void __init intel_cleanup_irq_remapping(void)
+{
+	struct dmar_drhd_unit *drhd;
+	struct intel_iommu *iommu;
+
+	for_each_iommu(iommu, drhd) {
+		if (ecap_ir_support(iommu->ecap)) {
+			iommu_disable_irq_remapping(iommu);
+			intel_teardown_irq_remapping(iommu);
+		}
+	}
+
+	if (x2apic_supported())
+		pr_warn("Failed to enable irq remapping.  You are vulnerable to irq-injection attacks.\n");
+}
+
+static int __init intel_prepare_irq_remapping(void)
 {
 	struct dmar_drhd_unit *drhd;
 	struct intel_iommu *iommu;
-	bool x2apic_present;
-	int setup = 0;
-	int eim = 0;
 
-	x2apic_present = x2apic_supported();
+	if (dmar_table_init() < 0)
+		return -1;
 
 	if (parse_ioapics_under_ir() != 1) {
-		printk(KERN_INFO "Not enable interrupt remapping\n");
+		printk(KERN_INFO "Not enabling interrupt remapping\n");
 		goto error;
 	}
 
-	if (x2apic_present) {
+	for_each_iommu(iommu, drhd) {
+		if (!ecap_ir_support(iommu->ecap))
+			continue;
+
+		/* Do the allocations early */
+		if (intel_setup_irq_remapping(iommu))
+			goto error;
+	}
+	return 0;
+error:
+	intel_cleanup_irq_remapping();
+	return -1;
+}
+
+static int __init intel_enable_irq_remapping(void)
+{
+	struct dmar_drhd_unit *drhd;
+	struct intel_iommu *iommu;
+	int setup = 0;
+	int eim = 0;
+
+	if (x2apic_supported()) {
 		pr_info("Queued invalidation will be enabled to support x2apic and Intr-remapping.\n");
 
 		eim = !dmar_x2apic_optout();
@@ -678,9 +713,6 @@ static int __init intel_enable_irq_remapping(void)
 		if (!ecap_ir_support(iommu->ecap))
 			continue;
 
-		if (intel_setup_irq_remapping(iommu))
-			goto error;
-
 		iommu_set_irq_remapping(iommu, eim);
 		setup = 1;
 	}
@@ -702,15 +734,7 @@ static int __init intel_enable_irq_remapping(void)
 	return eim ? IRQ_REMAP_X2APIC_MODE : IRQ_REMAP_XAPIC_MODE;
 
 error:
-	for_each_iommu(iommu, drhd)
-		if (ecap_ir_support(iommu->ecap)) {
-			iommu_disable_irq_remapping(iommu);
-			intel_teardown_irq_remapping(iommu);
-		}
-
-	if (x2apic_present)
-		pr_warn("Failed to enable irq remapping.  You are vulnerable to irq-injection attacks.\n");
-
+	intel_cleanup_irq_remapping();
 	return -1;
 }
 
@@ -1200,7 +1224,7 @@ static int intel_alloc_hpet_msi(unsigned int irq, unsigned int id)
 
 struct irq_remap_ops intel_irq_remap_ops = {
 	.supported		= intel_irq_remapping_supported,
-	.prepare		= dmar_table_init,
+	.prepare		= intel_prepare_irq_remapping,
 	.enable			= intel_enable_irq_remapping,
 	.disable		= disable_irq_remapping,
 	.reenable		= reenable_irq_remapping,

  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-bot for Thomas Gleixner [this message]
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 ` [Patch v2 07/16] x86/apic: Refine enable_IR_x2apic() and related functions Jiang Liu
2015-01-15  9:24   ` 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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