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* [dpdk-dev] [PATCH] doc: Add known issue for iommu and igb_uio
@ 2014-12-12 10:41 Sergio Gonzalez Monroy
  2014-12-12 12:06 ` [dpdk-dev] [PATCH v2] doc: add " Sergio Gonzalez Monroy
  0 siblings, 1 reply; 11+ messages in thread
From: Sergio Gonzalez Monroy @ 2014-12-12 10:41 UTC (permalink / raw)
  To: dev

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=y, Size: 4703 bytes --]

Known issue regarding iommu/VT-d and igb_uio on Linux kernel version
3.15 to 3.17 where unbinding the device from the driver removes the 1:1
mapping for the device on the iommu resulting in memory access errors.

Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
---
 doc/guides/rel_notes/known_issues.rst | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst
index 8ef654a..72bd0de 100644
--- a/doc/guides/rel_notes/known_issues.rst
+++ b/doc/guides/rel_notes/known_issues.rst
@@ -1026,3 +1026,35 @@ Stopping the port does not down the link on Intel® 40G ethernet controller
 | Driver/Module                  | Poll Mode Driver (PMD)                                                               |
 |                                |                                                                                      |
 +--------------------------------+--------------------------------------------------------------------------------------+
+
+Devices bound to igb_uio with VT-d enabled do not work on Linux* kernel 3.15-3.17
+---------------------------------------------------------------------------------
+
++--------------------------------+--------------------------------------------------------------------------------------+
+| Title                          | Devices bound to igb_uio with VT-d enabled do not work on Linux* kernel 3.15-3.17    |
+|                                |                                                                                      |
++================================+======================================================================================+
+| Reference #                    | IXA00373938                                                                          |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Description                    | When VT-d is enabled (iommu=pt intel_iommu=on), devices are 1:1 mapped.              |
+|                                | In the Linux* kernel unbinding devices from drivers removes that mapping which       |
+|                                | result in IOMMU errors.                                                              |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Implication                    | Devices will not be allowed to access memory.                                        |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Resolution/ Workaround         | Use earlier or later kernel versions, or avoid driver binding on boot by             |
+|                                | blacklisting the driver modules.                                                     |
+|                                | ie. in the case of ixgbe, we can pass the kernel command line option:                |
+|                                |     modprobe.blacklist=ixgbe                                                         |
+|                                | This way we do not need to unbind the device to bind it to igb_uio.                  |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Affected Environment/ Platform | Linux* systems with kernel versions 3.15 to 3.17                                     |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Driver/Module                  | igb_uio module                                                                       |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
-- 
1.9.3

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [dpdk-dev] [PATCH v2] doc: add known issue for iommu and igb_uio
  2014-12-12 10:41 [dpdk-dev] [PATCH] doc: Add known issue for iommu and igb_uio Sergio Gonzalez Monroy
@ 2014-12-12 12:06 ` Sergio Gonzalez Monroy
  2014-12-12 12:59   ` Nicolas Dichtel
  2014-12-12 14:43   ` [dpdk-dev] [PATCH v3] " Sergio Gonzalez Monroy
  0 siblings, 2 replies; 11+ messages in thread
From: Sergio Gonzalez Monroy @ 2014-12-12 12:06 UTC (permalink / raw)
  To: dev

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=y, Size: 4951 bytes --]

Known issue regarding iommu/VT-d and igb_uio on Linux kernel version
3.15 to 3.17 where unbinding the device from the driver removes the 1:1
mapping for the device on the iommu resulting in memory access errors.

Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
---
 doc/guides/rel_notes/known_issues.rst | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst
index 8ef654a..a8aab52 100644
--- a/doc/guides/rel_notes/known_issues.rst
+++ b/doc/guides/rel_notes/known_issues.rst
@@ -1026,3 +1026,37 @@ Stopping the port does not down the link on Intel® 40G ethernet controller
 | Driver/Module                  | Poll Mode Driver (PMD)                                                               |
 |                                |                                                                                      |
 +--------------------------------+--------------------------------------------------------------------------------------+
+
+Devices bound to igb_uio with VT-d enabled do not work on Linux* kernel 3.15-3.17
+---------------------------------------------------------------------------------
+
++--------------------------------+--------------------------------------------------------------------------------------+
+| Title                          | Devices bound to igb_uio with VT-d enabled do not work on Linux* kernel 3.15-3.17    |
+|                                |                                                                                      |
++================================+======================================================================================+
+| Reference #                    | IXA00373938                                                                          |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Description                    | When VT-d is enabled (iommu=pt intel_iommu=on), devices are 1:1 mapped.              |
+|                                | In the Linux* kernel unbinding devices from drivers removes that mapping which       |
+|                                | result in IOMMU errors.                                                              |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Implication                    | Devices will not be allowed to access memory.                                        |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Resolution/ Workaround         | Use earlier or later kernel versions, or avoid driver binding on boot by             |
+|                                | blacklisting the driver modules.                                                     |
+|                                | ie. in the case of ixgbe, we can pass the kernel command line option:                |
+|                                |                                                                                      |
+|                                |     modprobe.blacklist=ixgbe                                                         |
+|                                |                                                                                      |
+|                                | This way we do not need to unbind the device to bind it to igb_uio.                  |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Affected Environment/ Platform | Linux* systems with kernel versions 3.15 to 3.17                                     |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Driver/Module                  | igb_uio module                                                                       |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
-- 
1.9.3

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [dpdk-dev] [PATCH v2] doc: add known issue for iommu and igb_uio
  2014-12-12 12:06 ` [dpdk-dev] [PATCH v2] doc: add " Sergio Gonzalez Monroy
@ 2014-12-12 12:59   ` Nicolas Dichtel
  2014-12-12 13:20     ` Gonzalez Monroy, Sergio
  2014-12-12 14:43   ` [dpdk-dev] [PATCH v3] " Sergio Gonzalez Monroy
  1 sibling, 1 reply; 11+ messages in thread
From: Nicolas Dichtel @ 2014-12-12 12:59 UTC (permalink / raw)
  To: Sergio Gonzalez Monroy, dev

Le 12/12/2014 13:06, Sergio Gonzalez Monroy a écrit :
> Known issue regarding iommu/VT-d and igb_uio on Linux kernel version
> 3.15 to 3.17 where unbinding the device from the driver removes the 1:1
Do you mean that the problem doesn't exist with a linux 3.18?

> mapping for the device on the iommu resulting in memory access errors.
Do you have the linux commit id which introduces the problem? And the one which
solves it?

>
> Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
> ---
Please, also don't forget to explain what you have changed between the v1 and
v2.
The history should be put here, after the '---', something like:

v2: update that


Regards,
Nicolas

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [dpdk-dev] [PATCH v2] doc: add known issue for iommu and igb_uio
  2014-12-12 12:59   ` Nicolas Dichtel
@ 2014-12-12 13:20     ` Gonzalez Monroy, Sergio
  2014-12-12 13:28       ` Nicolas Dichtel
  0 siblings, 1 reply; 11+ messages in thread
From: Gonzalez Monroy, Sergio @ 2014-12-12 13:20 UTC (permalink / raw)
  To: nicolas.dichtel, dev

> From: Nicolas Dichtel [mailto:nicolas.dichtel@6wind.com]
> Sent: Friday, December 12, 2014 1:00 PM
> 
> Le 12/12/2014 13:06, Sergio Gonzalez Monroy a écrit :
> > Known issue regarding iommu/VT-d and igb_uio on Linux kernel version
> > 3.15 to 3.17 where unbinding the device from the driver removes the
> > 1:1
> Do you mean that the problem doesn't exist with a linux 3.18?
> 
Yes,  as it is mentioned in the resolution/workarounds, earlier or later kernels do solve the issue.

> > mapping for the device on the iommu resulting in memory access errors.
> Do you have the linux commit id which introduces the problem? And the one
> which solves it?
> 
I do have the commits, but I was not sure if I should add the info (at least no previous release note did).

Introduced in:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/iommu/intel-iommu.c?id=816997d03bca9fabcee65f3481eb0297103eceb7

Solved in:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/iommu/intel-iommu.c?id=1196c2fb0407683c2df92d3d09f9144d42830894

> >
> > Signed-off-by: Sergio Gonzalez Monroy
> > <sergio.gonzalez.monroy@intel.com>
> > ---
> Please, also don't forget to explain what you have changed between the v1
> and v2.
> The history should be put here, after the '---', something like:
> 
> v2: update that
> 
I did forget. I will add it for v3.
I need to fix issue with patch not  showing in patchwork (I think cause of R (registered) symbol in context line).

Regards,
Sergio
> 
> Regards,
> Nicolas

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [dpdk-dev] [PATCH v2] doc: add known issue for iommu and igb_uio
  2014-12-12 13:20     ` Gonzalez Monroy, Sergio
@ 2014-12-12 13:28       ` Nicolas Dichtel
  2014-12-12 13:38         ` Gonzalez Monroy, Sergio
  0 siblings, 1 reply; 11+ messages in thread
From: Nicolas Dichtel @ 2014-12-12 13:28 UTC (permalink / raw)
  To: Gonzalez Monroy, Sergio, dev

Le 12/12/2014 14:20, Gonzalez Monroy, Sergio a écrit :
>> From: Nicolas Dichtel [mailto:nicolas.dichtel@6wind.com]
>> Sent: Friday, December 12, 2014 1:00 PM
>>
>> Le 12/12/2014 13:06, Sergio Gonzalez Monroy a écrit :
>>> Known issue regarding iommu/VT-d and igb_uio on Linux kernel version
>>> 3.15 to 3.17 where unbinding the device from the driver removes the
>>> 1:1
>> Do you mean that the problem doesn't exist with a linux 3.18?
>>
> Yes,  as it is mentioned in the resolution/workarounds, earlier or later kernels do solve the issue.
Ok, I was not sure that the last version was tested ;-)

>
>>> mapping for the device on the iommu resulting in memory access errors.
>> Do you have the linux commit id which introduces the problem? And the one
>> which solves it?
>>
> I do have the commits, but I was not sure if I should add the info (at least no previous release note did).
>
> Introduced in:
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/iommu/intel-iommu.c?id=816997d03bca9fabcee65f3481eb0297103eceb7
>
> Solved in:
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/iommu/intel-iommu.c?id=1196c2fb0407683c2df92d3d09f9144d42830894
I think it's a very useful info.


Thank you,
Nicolas

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [dpdk-dev] [PATCH v2] doc: add known issue for iommu and igb_uio
  2014-12-12 13:28       ` Nicolas Dichtel
@ 2014-12-12 13:38         ` Gonzalez Monroy, Sergio
  2014-12-12 13:50           ` Nicolas Dichtel
  0 siblings, 1 reply; 11+ messages in thread
From: Gonzalez Monroy, Sergio @ 2014-12-12 13:38 UTC (permalink / raw)
  To: nicolas.dichtel, dev

> From: Nicolas Dichtel [mailto:nicolas.dichtel@6wind.com]
> Sent: Friday, December 12, 2014 1:28 PM
> 
> Le 12/12/2014 14:20, Gonzalez Monroy, Sergio a écrit :
> >> From: Nicolas Dichtel [mailto:nicolas.dichtel@6wind.com]
> >> Sent: Friday, December 12, 2014 1:00 PM
> >>
> >> Le 12/12/2014 13:06, Sergio Gonzalez Monroy a écrit :
> >>> mapping for the device on the iommu resulting in memory access errors.
> >> Do you have the linux commit id which introduces the problem? And the
> >> one which solves it?
> >>
> > I do have the commits, but I was not sure if I should add the info (at least
> no previous release note did).
> >
> > Introduced in:
> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit
> > /drivers/iommu/intel-
> iommu.c?id=816997d03bca9fabcee65f3481eb0297103ece
> > b7
> >
> > Solved in:
> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit
> > /drivers/iommu/intel-
> iommu.c?id=1196c2fb0407683c2df92d3d09f9144d428308
> > 94
> I think it's a very useful info.
> 
Alright, I will add it in the description of the release note.

Any ideas why patchwork is not showing these patches?
Mutt seems to be displaying the symbol fine.

Thanks,
Sergio

> 
> Thank you,
> Nicolas

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [dpdk-dev] [PATCH v2] doc: add known issue for iommu and igb_uio
  2014-12-12 13:38         ` Gonzalez Monroy, Sergio
@ 2014-12-12 13:50           ` Nicolas Dichtel
  2014-12-12 16:34             ` Thomas Monjalon
  0 siblings, 1 reply; 11+ messages in thread
From: Nicolas Dichtel @ 2014-12-12 13:50 UTC (permalink / raw)
  To: Gonzalez Monroy, Sergio, dev

Le 12/12/2014 14:38, Gonzalez Monroy, Sergio a écrit :
>> From: Nicolas Dichtel [mailto:nicolas.dichtel@6wind.com]
>> Sent: Friday, December 12, 2014 1:28 PM
>>
>> Le 12/12/2014 14:20, Gonzalez Monroy, Sergio a écrit :
>>>> From: Nicolas Dichtel [mailto:nicolas.dichtel@6wind.com]
>>>> Sent: Friday, December 12, 2014 1:00 PM
>>>>
>>>> Le 12/12/2014 13:06, Sergio Gonzalez Monroy a écrit :
>>>>> mapping for the device on the iommu resulting in memory access errors.
>>>> Do you have the linux commit id which introduces the problem? And the
>>>> one which solves it?
>>>>
>>> I do have the commits, but I was not sure if I should add the info (at least
>> no previous release note did).
>>>
>>> Introduced in:
>>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit
>>> /drivers/iommu/intel-
>> iommu.c?id=816997d03bca9fabcee65f3481eb0297103ece
>>> b7
>>>
>>> Solved in:
>>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit
>>> /drivers/iommu/intel-
>> iommu.c?id=1196c2fb0407683c2df92d3d09f9144d428308
>>> 94
>> I think it's a very useful info.
>>
> Alright, I will add it in the description of the release note.
>
> Any ideas why patchwork is not showing these patches?
No ...
Thomas, do you have an idea?


Regards,
Nicolas

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [dpdk-dev] [PATCH v3] doc: add known issue for iommu and igb_uio
  2014-12-12 12:06 ` [dpdk-dev] [PATCH v2] doc: add " Sergio Gonzalez Monroy
  2014-12-12 12:59   ` Nicolas Dichtel
@ 2014-12-12 14:43   ` Sergio Gonzalez Monroy
  2014-12-15 10:32     ` [dpdk-dev] [PATCH v4] " Sergio Gonzalez Monroy
  1 sibling, 1 reply; 11+ messages in thread
From: Sergio Gonzalez Monroy @ 2014-12-12 14:43 UTC (permalink / raw)
  To: dev

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=y, Size: 5621 bytes --]

Known issue regarding iommu/VT-d and igb_uio on Linux kernel version 3.15
to 3.17 where unbinding the device from the driver removes the 1:1 mapping
for the device on the iommu resulting in memory access errors.

Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
---
v3:
 Remove reference number
 Add Linux commit links

v2:
 Fix title uppercase
 Add extra blank line to show proper indentation

v1:
 Known igb_uio issue when iommu/vt-d is on

 doc/guides/rel_notes/known_issues.rst | 38 +++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst
index 8ef654a..0cfecab 100644
--- a/doc/guides/rel_notes/known_issues.rst
+++ b/doc/guides/rel_notes/known_issues.rst
@@ -1026,3 +1026,41 @@ Stopping the port does not down the link on Intel® 40G ethernet controller
 | Driver/Module                  | Poll Mode Driver (PMD)                                                               |
 |                                |                                                                                      |
 +--------------------------------+--------------------------------------------------------------------------------------+
+
+Devices bound to igb_uio with VT-d enabled do not work on Linux* kernel 3.15-3.17
+---------------------------------------------------------------------------------
+
++--------------------------------+--------------------------------------------------------------------------------------+
+| Title                          | Devices bound to igb_uio with VT-d enabled do not work on Linux* kernel 3.15-3.17    |
+|                                |                                                                                      |
++================================+======================================================================================+
+| Description                    | When VT-d is enabled (iommu=pt intel_iommu=on), devices are 1:1 mapped.              |
+|                                | In the Linux* kernel unbinding devices from drivers removes that mapping which       |
+|                                | result in IOMMU errors.                                                              |
+|                                |                                                                                      |
+|                                | Introduced in Linux `kernel 3.15 commit <https://git.kernel.org/cgit/linux/kernel/   |
+|                                | git/torvalds/linux.git/commit/drivers/iommu/                                         |
+|                                | intel-iommu.c?id=816997d03bca9fabcee65f3481eb0297103eceb7>`_,                        |
+|                                | solved in Linux `kernel 3.18 commit <https://git.kernel.org/cgit/linux/kernel/git/   |
+|                                | torvalds/linux.git/commit/drivers/iommu/                                             |
+|                                | intel-iommu.c?id=1196c2fb0407683c2df92d3d09f9144d42830894>`_.                        |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Implication                    | Devices will not be allowed to access memory.                                        |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Resolution/ Workaround         | Use earlier or later kernel versions, or avoid driver binding on boot by             |
+|                                | blacklisting the driver modules.                                                     |
+|                                | ie. in the case of ixgbe, we can pass the kernel command line option:                |
+|                                |                                                                                      |
+|                                |     modprobe.blacklist=ixgbe                                                         |
+|                                |                                                                                      |
+|                                | This way we do not need to unbind the device to bind it to igb_uio.                  |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Affected Environment/ Platform | Linux* systems with kernel versions 3.15 to 3.17                                     |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Driver/Module                  | igb_uio module                                                                       |
+|                                |                                                                                      |
++--------------------------------+--------------------------------------------------------------------------------------+
-- 
1.9.3

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [dpdk-dev] [PATCH v2] doc: add known issue for iommu and igb_uio
  2014-12-12 13:50           ` Nicolas Dichtel
@ 2014-12-12 16:34             ` Thomas Monjalon
  0 siblings, 0 replies; 11+ messages in thread
From: Thomas Monjalon @ 2014-12-12 16:34 UTC (permalink / raw)
  To: Gonzalez Monroy, Sergio; +Cc: dev

2014-12-12 14:50, Nicolas Dichtel:
> Le 12/12/2014 14:38, Gonzalez Monroy, Sergio a écrit :
> > Any ideas why patchwork is not showing these patches?
> 
> No ...
> Thomas, do you have an idea?

The parsemail script is responsible of adding new patches.
So I guess the answer (bug?) is in this file:
	http://git.ozlabs.org/?p=patchwork;a=blob;f=apps/patchwork/bin/parsemail.py

Sergio, maybe you could try the parsemail script locally with your patch.

-- 
Thomas

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [dpdk-dev] [PATCH v4] doc: add known issue for iommu and igb_uio
  2014-12-12 14:43   ` [dpdk-dev] [PATCH v3] " Sergio Gonzalez Monroy
@ 2014-12-15 10:32     ` Sergio Gonzalez Monroy
  2014-12-17 10:01       ` Iremonger, Bernard
  0 siblings, 1 reply; 11+ messages in thread
From: Sergio Gonzalez Monroy @ 2014-12-15 10:32 UTC (permalink / raw)
  To: dev

Known issue regarding iommu/VT-d and igb_uio in Linux kernel version 3.15
to 3.17 where unbinding the device from the driver removes the 1:1 mapping
in the iommu resulting in IOMMU/DMAR errors when the device tries to
access memory.

Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
---
v4:
 Improve commit log description
 Add kernel error message info
 Improve formatting
 Fix patch charset encoding

v3:
 Remove reference number
 Add Linux commit links

v2:
 Fix title uppercase
 Add extra blank line to show proper indentation

v1:
 Known igb_uio issue when iommu/vt-d is on

 doc/guides/rel_notes/known_issues.rst | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst
index 8ef654a..d26dcfa 100644
--- a/doc/guides/rel_notes/known_issues.rst
+++ b/doc/guides/rel_notes/known_issues.rst
@@ -1026,3 +1026,35 @@ Stopping the port does not down the link on Intel® 40G ethernet controller
 | Driver/Module                  | Poll Mode Driver (PMD)                                                               |
 |                                |                                                                                      |
 +--------------------------------+--------------------------------------------------------------------------------------+
+
+Devices bound to igb_uio with VT-d enabled do not work on Linux* kernel 3.15-3.17
+---------------------------------------------------------------------------------
+
++--------------------------------+--------------------------------------------------------------------------------------+
+| Title                          | Devices bound to igb_uio with VT-d enabled do not work on Linux* kernel 3.15-3.17    |
++================================+======================================================================================+
+| Description                    | | When VT-d is enabled (iommu=pt intel_iommu=on), devices are 1:1 mapped.            |
+|                                |   In the Linux* kernel unbinding devices from drivers removes that mapping which     |
+|                                |   result in IOMMU errors.                                                            |
+|                                | | Introduced in Linux `kernel 3.15 commit <https://git.kernel.org/cgit/linux/kernel/ |
+|                                |   git/torvalds/linux.git/commit/drivers/iommu/                                       |
+|                                |   intel-iommu.c?id=816997d03bca9fabcee65f3481eb0297103eceb7>`_,                      |
+|                                |   solved in Linux `kernel 3.18 commit <https://git.kernel.org/cgit/linux/kernel/git/ |
+|                                |   torvalds/linux.git/commit/drivers/iommu/                                           |
+|                                |   intel-iommu.c?id=1196c2fb0407683c2df92d3d09f9144d42830894>`_.                      |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Implication                    | | Devices will not be allowed to access memory, resulting in following kernel errors:|
+|                                | | ``dmar: DRHD: handling fault status reg 2``                                        |
+|                                | | ``dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr a0c58000``             |
+|                                | | ``DMAR:[fault reason 02] Present bit in context entry is clear``                   |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Resolution/ Workaround         | | Use earlier or later kernel versions, or avoid driver binding on boot by           |
+|                                |   blacklisting the driver modules.                                                   |
+|                                | | ie. in the case of ixgbe, we can pass the kernel command line option:              |
+|                                | | ``modprobe.blacklist=ixgbe``                                                       |
+|                                | | This way we do not need to unbind the device to bind it to igb_uio.                |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Affected Environment/ Platform | Linux* systems with kernel versions 3.15 to 3.17                                     |
++--------------------------------+--------------------------------------------------------------------------------------+
+| Driver/Module                  | igb_uio module                                                                       |
++--------------------------------+--------------------------------------------------------------------------------------+
-- 
1.9.3

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [dpdk-dev] [PATCH v4] doc: add known issue for iommu and igb_uio
  2014-12-15 10:32     ` [dpdk-dev] [PATCH v4] " Sergio Gonzalez Monroy
@ 2014-12-17 10:01       ` Iremonger, Bernard
  0 siblings, 0 replies; 11+ messages in thread
From: Iremonger, Bernard @ 2014-12-17 10:01 UTC (permalink / raw)
  To: Gonzalez Monroy, Sergio, dev

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Sergio Gonzalez Monroy
> Sent: Monday, December 15, 2014 10:33 AM
> To: dev@dpdk.org
> Subject: [dpdk-dev] [PATCH v4] doc: add known issue for iommu and igb_uio
> 
> Known issue regarding iommu/VT-d and igb_uio in Linux kernel version 3.15 to 3.17 where unbinding
> the device from the driver removes the 1:1 mapping in the iommu resulting in IOMMU/DMAR errors
> when the device tries to access memory.
> 
> Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>

Acked-by: Bernard Iremonger <bernard.iremonger@intel.com>

 I have applied the patch to my tree next/dpdk-doc.

^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2014-12-17 10:01 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-12-12 10:41 [dpdk-dev] [PATCH] doc: Add known issue for iommu and igb_uio Sergio Gonzalez Monroy
2014-12-12 12:06 ` [dpdk-dev] [PATCH v2] doc: add " Sergio Gonzalez Monroy
2014-12-12 12:59   ` Nicolas Dichtel
2014-12-12 13:20     ` Gonzalez Monroy, Sergio
2014-12-12 13:28       ` Nicolas Dichtel
2014-12-12 13:38         ` Gonzalez Monroy, Sergio
2014-12-12 13:50           ` Nicolas Dichtel
2014-12-12 16:34             ` Thomas Monjalon
2014-12-12 14:43   ` [dpdk-dev] [PATCH v3] " Sergio Gonzalez Monroy
2014-12-15 10:32     ` [dpdk-dev] [PATCH v4] " Sergio Gonzalez Monroy
2014-12-17 10:01       ` Iremonger, Bernard

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