linux-kernel - [PATCH] iommu/amd: Init unity mappings only for dma

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Date:	Wed, 13 Jul 2016 12:43:39 +0200
From:	Joerg Roedel <joro@...tes.org>
To:	iommu@...ts.linux-foundation.org
Cc:	linux-kernel@...r.kernel.org,
	Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>,
	Vincent.Wan@....com, Joerg Roedel <jroedel@...e.de>
Subject: [PATCH] iommu/amd: Init unity mappings only for dma_ops domains

From: Joerg Roedel <jroedel@...e.de>

The default domain for a device might also be
identity-mapped. In this case the kernel would crash when
unity mappings are defined for the device. Fix that by
making sure the domain is a dma_ops domain.

Fixes: 0bb6e243d7fb ('iommu/amd: Support IOMMU_DOMAIN_DMA type allocation')
Cc: stable@...r.kernel.org # v4.2+
Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 drivers/iommu/amd_iommu.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 921111e..b938a4a 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -467,9 +467,11 @@ static void init_iommu_group(struct device *dev)
 	if (!domain)
 		goto out;
 
-	dma_domain = to_pdomain(domain)->priv;
+	if (to_pdomain(domain)->flags == PD_DMA_OPS_MASK) {
+		dma_domain = to_pdomain(domain)->priv;
+		init_unity_mappings_for_device(dev, dma_domain);
+	}
 
-	init_unity_mappings_for_device(dev, dma_domain);
 out:
 	iommu_group_put(group);
 }
-- 
2.6.6