linux-kernel - [PATCH 08/10] iommu/vtd: assign new page table for dma

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Date:	Mon, 15 Dec 2014 17:53:04 +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>, <billsumnerlinux@...il.com>,
	<zhen-hual@...com>
Cc:	<iommu@...ts.linux-foundation.org>, <kexec@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <linux-pci@...r.kernel.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>
Subject: [PATCH 08/10] iommu/vtd: assign new page table for dma_map

When a device driver issues the first dma_map command for a
device, we assign a new and empty page-table, thus removing all
mappings from the old kernel for the device.

Signed-off-by: Li, Zhen-Hua <zhen-hual@...com>
---
 drivers/iommu/intel-iommu.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 4837ce5..f11a9b1 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3200,15 +3200,28 @@ static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
 	}
 
 	/* make sure context mapping is ok */
-	if (unlikely(!domain_context_mapped(dev))) {
-		ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
-		if (ret) {
-			printk(KERN_ERR "Domain context map for %s failed",
-			       dev_name(dev));
-			return NULL;
-		}
+	if (likely(domain_context_mapped(dev))) {
+#ifdef CONFIG_CRASH_DUMP
+		if (is_kdump_kernel()) {
+			domain_exit(domain);
+			domain = get_domain_for_dev(dev,
+				DEFAULT_DOMAIN_ADDRESS_WIDTH);
+			if (!domain) {
+				pr_err("Allocating domain for %s failed",
+				       dev_name(dev));
+				return NULL;
+			}
+		} else
+#endif
+			return domain;
 	}
 
+	ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
+	if (ret) {
+		pr_err("Domain context map for %s failed",
+		       dev_name(dev));
+		return NULL;
+	}
 	return domain;
 }
 
-- 
2.0.0-rc0

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