* [PATCH 3.2] iommu/amd: Initialize device table after dma_ops
@ 2013-02-28 21:39 Shuah Khan
2013-03-02 23:00 ` Ben Hutchings
0 siblings, 1 reply; 4+ messages in thread
From: Shuah Khan @ 2013-02-28 21:39 UTC (permalink / raw)
To: Joerg Roedel; +Cc: iommu, LKML, stable, Greg KH, ben, shuahkhan
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@8bytes.org>
Signed-off-by: Shuah Khan <shuah.khan@hp.com>
CC: stable@vger.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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 3.2] iommu/amd: Initialize device table after dma_ops
2013-02-28 21:39 [PATCH 3.2] iommu/amd: Initialize device table after dma_ops Shuah Khan
@ 2013-03-02 23:00 ` Ben Hutchings
2013-03-03 22:58 ` Joerg Roedel
0 siblings, 1 reply; 4+ messages in thread
From: Ben Hutchings @ 2013-03-02 23:00 UTC (permalink / raw)
To: shuah.khan; +Cc: Joerg Roedel, iommu, LKML, stable, Greg KH, shuahkhan
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On Thu, 2013-02-28 at 14:39 -0700, Shuah Khan wrote:
> 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@8bytes.org>
> Signed-off-by: Shuah Khan <shuah.khan@hp.com>
> CC: stable@vger.kernel.org 3.2
I'm not convinced about this backport, because the order of
initialisation already changed a lot after 3.2 and before the upstream
commit. So I'm going to wait for Joerg to confirm that this makes sense
before adding it to the patch queue.
Ben.
> ---
> 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();
--
Ben Hutchings
Computers are not intelligent. They only think they are.
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 3.2] iommu/amd: Initialize device table after dma_ops
2013-03-02 23:00 ` Ben Hutchings
@ 2013-03-03 22:58 ` Joerg Roedel
2013-03-17 3:42 ` Ben Hutchings
0 siblings, 1 reply; 4+ messages in thread
From: Joerg Roedel @ 2013-03-03 22:58 UTC (permalink / raw)
To: Ben Hutchings; +Cc: shuah.khan, iommu, LKML, stable, Greg KH, shuahkhan
Hi Ben,
On Sat, Mar 02, 2013 at 11:00:35PM +0000, Ben Hutchings wrote:
> I'm not convinced about this backport, because the order of
> initialisation already changed a lot after 3.2 and before the upstream
> commit. So I'm going to wait for Joerg to confirm that this makes sense
> before adding it to the patch queue.
The patch looks good, it fixes a race condition during amd_iommu
initialization. I'll also gave the backport a test to be sure it
doesn't break anything.
Thanks,
Joerg
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 3.2] iommu/amd: Initialize device table after dma_ops
2013-03-03 22:58 ` Joerg Roedel
@ 2013-03-17 3:42 ` Ben Hutchings
0 siblings, 0 replies; 4+ messages in thread
From: Ben Hutchings @ 2013-03-17 3:42 UTC (permalink / raw)
To: Joerg Roedel; +Cc: shuah.khan, iommu, LKML, stable, Greg KH, shuahkhan
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On Sun, 2013-03-03 at 23:58 +0100, Joerg Roedel wrote:
> Hi Ben,
>
> On Sat, Mar 02, 2013 at 11:00:35PM +0000, Ben Hutchings wrote:
> > I'm not convinced about this backport, because the order of
> > initialisation already changed a lot after 3.2 and before the upstream
> > commit. So I'm going to wait for Joerg to confirm that this makes sense
> > before adding it to the patch queue.
>
> The patch looks good, it fixes a race condition during amd_iommu
> initialization. I'll also gave the backport a test to be sure it
> doesn't break anything.
Applied, thanks all.
Ben.
--
Ben Hutchings
Usenet is essentially a HUGE group of people passing notes in class.
- Rachel Kadel, `A Quick Guide to Newsgroup Etiquette'
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2013-02-28 21:39 [PATCH 3.2] iommu/amd: Initialize device table after dma_ops Shuah Khan
2013-03-02 23:00 ` Ben Hutchings
2013-03-03 22:58 ` Joerg Roedel
2013-03-17 3:42 ` Ben Hutchings
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