From: Joerg Roedel <joro@8bytes.org>
To: Shuah Khan <shuahkhan@gmail.com>
Cc: Shuah Khan <shuah.khan@hp.com>,
LKML <linux-kernel@vger.kernel.org>,
stable <stable@vger.kernel.org>,
iommu@lists.linux-foundation.org
Subject: Re: IO_PAGE_FAULTs on unity mapped regions during amd_iommu_init() in Linux 3.4
Date: Wed, 6 Feb 2013 13:12:23 +0100 [thread overview]
Message-ID: <20130206121223.GT25591@8bytes.org> (raw)
In-Reply-To: <CAKocOOO6Z2LyLYiuQMWf4iv4PAP8h5jbNWxRcSXKgXD1es6GYg@mail.gmail.com>
On Tue, Feb 05, 2013 at 06:57:21AM -0700, Shuah Khan wrote:
> Thanks much. I will hang on to this test system for testing your fix.
Okay, here is the simple fix for v3.8-rc6. I guess it is not
straighforward to port it to v3.4, but it should be doable.
>From 2ecf57c85e67e0243b36b787d0490c0b47202ba8 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <joro@8bytes.org>
Date: Wed, 6 Feb 2013 12:55:23 +0100
Subject: [PATCH] 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.
Signed-off-by: Joerg Roedel <joro@8bytes.org>
---
drivers/iommu/amd_iommu_init.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index faf10ba..b6ecddb 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1876,11 +1876,6 @@ static int amd_iommu_init_dma(void)
struct amd_iommu *iommu;
int ret;
- init_device_table_dma();
-
- for_each_iommu(iommu)
- iommu_flush_all_caches(iommu);
-
if (iommu_pass_through)
ret = amd_iommu_init_passthrough();
else
@@ -1889,6 +1884,11 @@ static int amd_iommu_init_dma(void)
if (ret)
return ret;
+ init_device_table_dma();
+
+ for_each_iommu(iommu)
+ iommu_flush_all_caches(iommu);
+
amd_iommu_init_api();
amd_iommu_init_notifier();
--
1.7.9.5
next prev parent reply other threads:[~2013-02-06 12:12 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-31 18:33 IO_PAGE_FAULTs on unity mapped regions during amd_iommu_init() in Linux 3.4 Shuah Khan
2013-02-01 13:00 ` Joerg Roedel
2013-02-01 18:31 ` Shuah Khan
2013-02-05 13:31 ` Joerg Roedel
2013-02-05 13:57 ` Shuah Khan
2013-02-06 12:12 ` Joerg Roedel [this message]
2013-02-07 2:40 ` Shuah Khan
2013-02-11 19:49 ` Greg KH
2013-02-11 20:17 ` Shuah Khan
2013-02-11 20:57 ` Shuah Khan
2013-02-11 22:18 ` Joerg Roedel
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