2012-06-06 16:50:10

by Shuah Khan

Subject: [PATCH RFC] iommu/amd: Fix missing iommu_shutdown initialization in passthrough mode

Change AMD iommu driver to call disable iommus in pass-through mode. AMD
iommu driver's amd_iommu_init() routine doesn't initialize iommu_shutdown
in pass-through mode. As a result iommu disable via a call to disable_iommus()
doesn't happen at shutdown. Enable and disable of iommus is inconsistent in
pass-through mode. IOMMU is enabled, but not disabled. IOMMU disable is called
from error legs in amd_iommu_init() in pass-through mode.

Requesting for comments as I don't have access to AMD system that supports
IOMMU. I tested the change on AMD platforms with GART IOMMU which is not
sufficient.

Signed-off-by: Shuah Khan <[email protected]>
---
drivers/iommu/amd_iommu_init.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index c567903..1d8ab7f 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1644,6 +1644,8 @@ static int __init amd_iommu_init(void)

amd_iommu_init_api();

+ x86_platform.iommu_shutdown = disable_iommus;
+
if (iommu_pass_through)
goto out;

@@ -1652,8 +1654,6 @@ static int __init amd_iommu_init(void)
else
printk(KERN_INFO "AMD-Vi: Lazy IO/TLB flushing enabled\n");

- x86_platform.iommu_shutdown = disable_iommus;
-
out:
return ret;

--
1.7.9.5

2012-06-07 09:32:43

by Joerg Roedel

Subject: Re: [PATCH RFC] iommu/amd: Fix missing iommu_shutdown initialization in passthrough mode

On Wed, Jun 06, 2012 at 10:50:06AM -0600, Shuah Khan wrote:
> Change AMD iommu driver to call disable iommus in pass-through mode. AMD
> iommu driver's amd_iommu_init() routine doesn't initialize iommu_shutdown
> in pass-through mode. As a result iommu disable via a call to disable_iommus()
> doesn't happen at shutdown. Enable and disable of iommus is inconsistent in
> pass-through mode. IOMMU is enabled, but not disabled. IOMMU disable is called
> from error legs in amd_iommu_init() in pass-through mode.
>
> Requesting for comments as I don't have access to AMD system that supports
> IOMMU. I tested the change on AMD platforms with GART IOMMU which is not
> sufficient.
>
> Signed-off-by: Shuah Khan <[email protected]>

The patch is fine. Thanks, applied to iommu/fixes.

--
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