linux-kernel - [PATCH 3.2] iommu/amd: Initialize device table after dma

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Date:	Thu, 28 Feb 2013 14:39:50 -0700
From:	Shuah Khan <shuah.khan@...com>
To:	Joerg Roedel <joro@...tes.org>
Cc:	iommu@...ts.linux-foundation.org,
	LKML <linux-kernel@...r.kernel.org>,
	stable <stable@...r.kernel.org>,
	Greg KH <gregkh@...uxfoundation.org>, ben@...adent.org.uk,
	shuahkhan@...il.com
Subject: [PATCH 3.2] iommu/amd: Initialize device table after dma_ops

When dma_ops are initialized the unity mappings are created. The
init_device_table_dma() function makes sure DMA from all devices is
blocked by default. This opens a short window in time where DMA to
unity mapped regions is blocked by the IOMMU. Make sure this does not
happen by initializing the device table after dma_ops.

Back-port upstream commit: f528d980c17b8714aedc918ba86e058af914d66b
Tested on 3.2.38

Signed-off-by: Joerg Roedel <joro@...tes.org>
Signed-off-by: Shuah Khan <shuah.khan@...com>
CC: stable@...r.kernel.org 3.2
---
 drivers/iommu/amd_iommu_init.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 62a4d5c..b7d1cdd 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1396,6 +1396,7 @@ static struct syscore_ops amd_iommu_syscore_ops = {
  */
 static int __init amd_iommu_init(void)
 {
+	struct amd_iommu *iommu;
 	int i, ret = 0;
 
 	/*
@@ -1444,9 +1445,6 @@ static int __init amd_iommu_init(void)
 	if (amd_iommu_pd_alloc_bitmap == NULL)
 		goto free;
 
-	/* init the device table */
-	init_device_table();
-
 	/*
 	 * let all alias entries point to itself
 	 */
@@ -1496,6 +1494,12 @@ static int __init amd_iommu_init(void)
 	if (ret)
 		goto free_disable;
 
+	/* init the device table */
+	init_device_table();
+
+	for_each_iommu(iommu)
+		iommu_flush_all_caches(iommu);
+
 	amd_iommu_init_api();
 
 	amd_iommu_init_notifier();
-- 
1.7.10.4



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