[PATCH 08/10] iommu/vtd: assign new page table for dma_map

["Li, Zhen-Hua" <zhen-hual-VXdhtT5mjnY@public.gmane.org>]

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-VXdhtT5mjnY@public.gmane.org>
---
 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