linux-kernel - [PATCH 10/10] iommu/vt-d: Use old irte in kdump kernel

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Message-Id: <1419239729-26529-11-git-send-email-zhen-hual@hp.com>
Date:	Mon, 22 Dec 2014 17:15:29 +0800
From:	"Li, Zhen-Hua" <zhen-hual@...com>
To:	<dwmw2@...radead.org>, <indou.takao@...fujitsu.com>,
	<bhe@...hat.com>, <joro@...tes.org>, <vgoyal@...hat.com>,
	<dyoung@...hat.com>
Cc:	<iommu@...ts.linux-foundation.org>, <linux-kernel@...r.kernel.org>,
	<linux-pci@...r.kernel.org>, <kexec@...ts.infradead.org>,
	<alex.williamson@...hat.com>, <ddutile@...hat.com>,
	<ishii.hironobu@...fujitsu.com>, <bhelgaas@...gle.com>,
	<doug.hatch@...com>, <jerry.hoemann@...com>, <tom.vaden@...com>,
	<li.zhang6@...com>, <lisa.mitchell@...com>,
	<billsumnerlinux@...il.com>, <zhen-hual@...com>
Subject: [PATCH 10/10] iommu/vt-d: Use old irte in kdump kernel

Fix the intr-remapping fault.

[1.594890] dmar: DRHD: handling fault status reg 2
[1.594894] dmar: INTR-REMAP: Request device [[41:00.0] fault index 4d
[1.594894] INTR-REMAP:[fault reason 34] Present field in the IRTE entry
is clear

Use old irte in kdump kernel, do not disable and re-enable interrupt
remapping.

Signed-off-by: Li, Zhen-Hua <zhen-hual@...com>
---
 drivers/iommu/intel_irq_remapping.c | 42 ++++++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 13f2034..e244186 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -198,6 +198,11 @@ static int modify_irte(int irq, struct irte *irte_modified)
 
 	set_64bit(&irte->low, irte_modified->low);
 	set_64bit(&irte->high, irte_modified->high);
+
+#ifdef CONFIG_CRASH_DUMP
+	if (is_kdump_kernel())
+		__iommu_update_old_irte(iommu, index);
+#endif
 	__iommu_flush_cache(iommu, irte, sizeof(*irte));
 
 	rc = qi_flush_iec(iommu, index, 0);
@@ -259,6 +264,11 @@ static int clear_entries(struct irq_2_iommu *irq_iommu)
 	bitmap_release_region(iommu->ir_table->bitmap, index,
 			      irq_iommu->irte_mask);
 
+#ifdef CONFIG_CRASH_DUMP
+	if (is_kdump_kernel())
+		__iommu_update_old_irte(iommu, -1);
+#endif
+
 	return qi_flush_iec(iommu, index, irq_iommu->irte_mask);
 }
 
@@ -640,11 +650,20 @@ static int __init intel_enable_irq_remapping(void)
 		 */
 		dmar_fault(-1, iommu);
 
-		/*
-		 * Disable intr remapping and queued invalidation, if already
-		 * enabled prior to OS handover.
-		 */
-		iommu_disable_irq_remapping(iommu);
+#ifdef CONFIG_CRASH_DUMP
+		if (is_kdump_kernel()) {
+			/* Do notdisable irq and then re-enable again. */
+		} else {
+#endif
+			/*
+			 * Disable intr remapping and queued invalidation,
+			 * if already enabled prior to OS handover.
+			 */
+			iommu_disable_irq_remapping(iommu);
+
+#ifdef CONFIG_CRASH_DUMP
+		}
+#endif
 
 		dmar_disable_qi(iommu);
 	}
@@ -687,7 +706,20 @@ static int __init intel_enable_irq_remapping(void)
 		if (intel_setup_irq_remapping(iommu))
 			goto error;
 
+#ifdef CONFIG_CRASH_DUMP
+	if (is_kdump_kernel()) {
+		unsigned long long q;
+
+		q = dmar_readq(iommu->reg + DMAR_IRTA_REG);
+		iommu->ir_table->base_old_phys = q & VTD_PAGE_MASK;
+		iommu->ir_table->base_old_virt = ioremap_cache(
+				iommu->ir_table->base_old_phys,
+				INTR_REMAP_TABLE_ENTRIES*sizeof(struct irte));
+		__iommu_load_old_irte(iommu);
+	} else
+#endif
 		iommu_set_irq_remapping(iommu, eim);
+
 		setup = 1;
 	}
 
-- 
2.0.0-rc0

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