diff mbox

[V11,08/11] drivers: acpi: Handle IOMMU lookup failure with deferred probing or error

Message ID 20170523085241.GA18204@red-moon (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Lorenzo Pieralisi May 23, 2017, 8:52 a.m. UTC
On Tue, May 23, 2017 at 02:26:10AM -0400, Nate Watterson wrote:
> Hi Sricharan,
> 
> On 4/10/2017 7:21 AM, Sricharan R wrote:
> >This is an equivalent to the DT's handling of the iommu master's probe
> >with deferred probing when the corrsponding iommu is not probed yet.
> >The lack of a registered IOMMU can be caused by the lack of a driver for
> >the IOMMU, the IOMMU device probe not having been performed yet, having
> >been deferred, or having failed.
> >
> >The first case occurs when the firmware describes the bus master and
> >IOMMU topology correctly but no device driver exists for the IOMMU yet
> >or the device driver has not been compiled in. Return NULL, the caller
> >will configure the device without an IOMMU.
> >
> >The second and third cases are handled by deferring the probe of the bus
> >master device which will eventually get reprobed after the IOMMU.
> >
> >The last case is currently handled by deferring the probe of the bus
> >master device as well. A mechanism to either configure the bus master
> >device without an IOMMU or to fail the bus master device probe depending
> >on whether the IOMMU is optional or mandatory would be a good
> >enhancement.
> >
> >Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
> >Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> >[Lorenzo: Added fixes for dma_coherent_mask overflow, acpi_dma_configure
> >           called multiple times for same device]
> >Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> >Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> >---
> >  drivers/acpi/arm64/iort.c  | 33 ++++++++++++++++++++++++++++++++-
> >  drivers/acpi/scan.c        | 11 ++++++++---
> >  drivers/base/dma-mapping.c |  2 +-
> >  include/acpi/acpi_bus.h    |  2 +-
> >  include/linux/acpi.h       |  7 +++++--
> >  5 files changed, 47 insertions(+), 8 deletions(-)
> >
> >diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> >index 3dd9ec3..e323ece 100644
> >--- a/drivers/acpi/arm64/iort.c
> >+++ b/drivers/acpi/arm64/iort.c
> >@@ -543,6 +543,14 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
> >  	const struct iommu_ops *ops = NULL;
> >  	int ret = -ENODEV;
> >  	struct fwnode_handle *iort_fwnode;
> >+	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
> >+
> >+	/*
> >+	 * If we already translated the fwspec there
> >+	 * is nothing left to do, return the iommu_ops.
> >+	 */
> >+	if (fwspec && fwspec->ops)
> >+		return fwspec->ops;
> 
> Is this logic strictly required? It breaks masters with multiple SIDs
> as only the first SID is actually added to the master's fwspec.

My bad, that's indeed a silly bug I introduced. Please let me know if the
patch below fixes it, we will send it upstream shortly.

Lorenzo

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Comments

Sricharan Ramabadhran May 23, 2017, 9:01 a.m. UTC | #1
Hi Lorenzo,

On 5/23/2017 2:22 PM, Lorenzo Pieralisi wrote:
> On Tue, May 23, 2017 at 02:26:10AM -0400, Nate Watterson wrote:
>> Hi Sricharan,
>>
>> On 4/10/2017 7:21 AM, Sricharan R wrote:
>>> This is an equivalent to the DT's handling of the iommu master's probe
>>> with deferred probing when the corrsponding iommu is not probed yet.
>>> The lack of a registered IOMMU can be caused by the lack of a driver for
>>> the IOMMU, the IOMMU device probe not having been performed yet, having
>>> been deferred, or having failed.
>>>
>>> The first case occurs when the firmware describes the bus master and
>>> IOMMU topology correctly but no device driver exists for the IOMMU yet
>>> or the device driver has not been compiled in. Return NULL, the caller
>>> will configure the device without an IOMMU.
>>>
>>> The second and third cases are handled by deferring the probe of the bus
>>> master device which will eventually get reprobed after the IOMMU.
>>>
>>> The last case is currently handled by deferring the probe of the bus
>>> master device as well. A mechanism to either configure the bus master
>>> device without an IOMMU or to fail the bus master device probe depending
>>> on whether the IOMMU is optional or mandatory would be a good
>>> enhancement.
>>>
>>> Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
>>> Reviewed-by: Robin Murphy <robin.murphy@arm.com>
>>> [Lorenzo: Added fixes for dma_coherent_mask overflow, acpi_dma_configure
>>>           called multiple times for same device]
>>> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>>> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
>>> ---
>>>  drivers/acpi/arm64/iort.c  | 33 ++++++++++++++++++++++++++++++++-
>>>  drivers/acpi/scan.c        | 11 ++++++++---
>>>  drivers/base/dma-mapping.c |  2 +-
>>>  include/acpi/acpi_bus.h    |  2 +-
>>>  include/linux/acpi.h       |  7 +++++--
>>>  5 files changed, 47 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
>>> index 3dd9ec3..e323ece 100644
>>> --- a/drivers/acpi/arm64/iort.c
>>> +++ b/drivers/acpi/arm64/iort.c
>>> @@ -543,6 +543,14 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
>>>  	const struct iommu_ops *ops = NULL;
>>>  	int ret = -ENODEV;
>>>  	struct fwnode_handle *iort_fwnode;
>>> +	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
>>> +
>>> +	/*
>>> +	 * If we already translated the fwspec there
>>> +	 * is nothing left to do, return the iommu_ops.
>>> +	 */
>>> +	if (fwspec && fwspec->ops)
>>> +		return fwspec->ops;
>>
>> Is this logic strictly required? It breaks masters with multiple SIDs
>> as only the first SID is actually added to the master's fwspec.
> 
> My bad, that's indeed a silly bug I introduced. Please let me know if the
> patch below fixes it, we will send it upstream shortly.
> 

oops, i think emails crossed. Please let me know if you are ok to add this
to the other fixes.

Regards,
 Sricharan

> Lorenzo
> 
> -- >8 --
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index c5fecf9..e326f2a 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -666,14 +666,6 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
>  	int ret = -ENODEV;
>  	struct fwnode_handle *iort_fwnode;
>  
> -	/*
> -	 * If we already translated the fwspec there
> -	 * is nothing left to do, return the iommu_ops.
> -	 */
> -	ops = iort_fwspec_iommu_ops(dev->iommu_fwspec);
> -	if (ops)
> -		return ops;
> -
>  	if (node) {
>  		iort_fwnode = iort_get_fwnode(node);
>  		if (!iort_fwnode)
> @@ -735,6 +727,14 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
>  	u32 streamid = 0;
>  	int err;
>  
> +	/*
> +	 * If we already translated the fwspec there
> +	 * is nothing left to do, return the iommu_ops.
> +	 */
> +	ops = iort_fwspec_iommu_ops(dev->iommu_fwspec);
> +	if (ops)
> +		return ops;
> +
>  	if (dev_is_pci(dev)) {
>  		struct pci_bus *bus = to_pci_dev(dev)->bus;
>  		u32 rid;
> 
>
Lorenzo Pieralisi May 23, 2017, 9:26 a.m. UTC | #2
On Tue, May 23, 2017 at 02:31:17PM +0530, Sricharan R wrote:
> Hi Lorenzo,
> 
> On 5/23/2017 2:22 PM, Lorenzo Pieralisi wrote:
> > On Tue, May 23, 2017 at 02:26:10AM -0400, Nate Watterson wrote:
> >> Hi Sricharan,
> >>
> >> On 4/10/2017 7:21 AM, Sricharan R wrote:
> >>> This is an equivalent to the DT's handling of the iommu master's probe
> >>> with deferred probing when the corrsponding iommu is not probed yet.
> >>> The lack of a registered IOMMU can be caused by the lack of a driver for
> >>> the IOMMU, the IOMMU device probe not having been performed yet, having
> >>> been deferred, or having failed.
> >>>
> >>> The first case occurs when the firmware describes the bus master and
> >>> IOMMU topology correctly but no device driver exists for the IOMMU yet
> >>> or the device driver has not been compiled in. Return NULL, the caller
> >>> will configure the device without an IOMMU.
> >>>
> >>> The second and third cases are handled by deferring the probe of the bus
> >>> master device which will eventually get reprobed after the IOMMU.
> >>>
> >>> The last case is currently handled by deferring the probe of the bus
> >>> master device as well. A mechanism to either configure the bus master
> >>> device without an IOMMU or to fail the bus master device probe depending
> >>> on whether the IOMMU is optional or mandatory would be a good
> >>> enhancement.
> >>>
> >>> Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
> >>> Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> >>> [Lorenzo: Added fixes for dma_coherent_mask overflow, acpi_dma_configure
> >>>           called multiple times for same device]
> >>> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> >>> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> >>> ---
> >>>  drivers/acpi/arm64/iort.c  | 33 ++++++++++++++++++++++++++++++++-
> >>>  drivers/acpi/scan.c        | 11 ++++++++---
> >>>  drivers/base/dma-mapping.c |  2 +-
> >>>  include/acpi/acpi_bus.h    |  2 +-
> >>>  include/linux/acpi.h       |  7 +++++--
> >>>  5 files changed, 47 insertions(+), 8 deletions(-)
> >>>
> >>> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> >>> index 3dd9ec3..e323ece 100644
> >>> --- a/drivers/acpi/arm64/iort.c
> >>> +++ b/drivers/acpi/arm64/iort.c
> >>> @@ -543,6 +543,14 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
> >>>  	const struct iommu_ops *ops = NULL;
> >>>  	int ret = -ENODEV;
> >>>  	struct fwnode_handle *iort_fwnode;
> >>> +	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
> >>> +
> >>> +	/*
> >>> +	 * If we already translated the fwspec there
> >>> +	 * is nothing left to do, return the iommu_ops.
> >>> +	 */
> >>> +	if (fwspec && fwspec->ops)
> >>> +		return fwspec->ops;
> >>
> >> Is this logic strictly required? It breaks masters with multiple SIDs
> >> as only the first SID is actually added to the master's fwspec.
> > 
> > My bad, that's indeed a silly bug I introduced. Please let me know if the
> > patch below fixes it, we will send it upstream shortly.
> > 
> 
> oops, i think emails crossed. Please let me know if you are ok to add
> this to the other fixes.

No worries, yes I am ok thanks but please give Nate some time to report
back to make sure the diff I sent actually fixes the problem.

Apologies for the breakage.

Lorenzo

> 
> Regards,
>  Sricharan
> 
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Nate Watterson May 23, 2017, 11:27 a.m. UTC | #3
Hi Lorenzo,

On 5/23/2017 5:26 AM, Lorenzo Pieralisi wrote:
> On Tue, May 23, 2017 at 02:31:17PM +0530, Sricharan R wrote:
>> Hi Lorenzo,
>>
>> On 5/23/2017 2:22 PM, Lorenzo Pieralisi wrote:
>>> On Tue, May 23, 2017 at 02:26:10AM -0400, Nate Watterson wrote:
>>>> Hi Sricharan,
>>>>
>>>> On 4/10/2017 7:21 AM, Sricharan R wrote:
>>>>> This is an equivalent to the DT's handling of the iommu master's probe
>>>>> with deferred probing when the corrsponding iommu is not probed yet.
>>>>> The lack of a registered IOMMU can be caused by the lack of a driver for
>>>>> the IOMMU, the IOMMU device probe not having been performed yet, having
>>>>> been deferred, or having failed.
>>>>>
>>>>> The first case occurs when the firmware describes the bus master and
>>>>> IOMMU topology correctly but no device driver exists for the IOMMU yet
>>>>> or the device driver has not been compiled in. Return NULL, the caller
>>>>> will configure the device without an IOMMU.
>>>>>
>>>>> The second and third cases are handled by deferring the probe of the bus
>>>>> master device which will eventually get reprobed after the IOMMU.
>>>>>
>>>>> The last case is currently handled by deferring the probe of the bus
>>>>> master device as well. A mechanism to either configure the bus master
>>>>> device without an IOMMU or to fail the bus master device probe depending
>>>>> on whether the IOMMU is optional or mandatory would be a good
>>>>> enhancement.
>>>>>
>>>>> Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
>>>>> Reviewed-by: Robin Murphy <robin.murphy@arm.com>
>>>>> [Lorenzo: Added fixes for dma_coherent_mask overflow, acpi_dma_configure
>>>>>            called multiple times for same device]
>>>>> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>>>>> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
>>>>> ---
>>>>>   drivers/acpi/arm64/iort.c  | 33 ++++++++++++++++++++++++++++++++-
>>>>>   drivers/acpi/scan.c        | 11 ++++++++---
>>>>>   drivers/base/dma-mapping.c |  2 +-
>>>>>   include/acpi/acpi_bus.h    |  2 +-
>>>>>   include/linux/acpi.h       |  7 +++++--
>>>>>   5 files changed, 47 insertions(+), 8 deletions(-)
>>>>>
>>>>> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
>>>>> index 3dd9ec3..e323ece 100644
>>>>> --- a/drivers/acpi/arm64/iort.c
>>>>> +++ b/drivers/acpi/arm64/iort.c
>>>>> @@ -543,6 +543,14 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
>>>>>   	const struct iommu_ops *ops = NULL;
>>>>>   	int ret = -ENODEV;
>>>>>   	struct fwnode_handle *iort_fwnode;
>>>>> +	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
>>>>> +
>>>>> +	/*
>>>>> +	 * If we already translated the fwspec there
>>>>> +	 * is nothing left to do, return the iommu_ops.
>>>>> +	 */
>>>>> +	if (fwspec && fwspec->ops)
>>>>> +		return fwspec->ops;
>>>>
>>>> Is this logic strictly required? It breaks masters with multiple SIDs
>>>> as only the first SID is actually added to the master's fwspec.
>>>
>>> My bad, that's indeed a silly bug I introduced. Please let me know if the
>>> patch below fixes it, we will send it upstream shortly.
>>>
>>
>> oops, i think emails crossed. Please let me know if you are ok to add
>> this to the other fixes.
> 
> No worries, yes I am ok thanks but please give Nate some time to report
> back to make sure the diff I sent actually fixes the problem.

The patch you sent fixes the problem. Thanks for the quick turnaround.

> 
> Apologies for the breakage.
> 
> Lorenzo
> 
>>
>> Regards,
>>   Sricharan
>>
diff mbox

Patch

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index c5fecf9..e326f2a 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -666,14 +666,6 @@  static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
 	int ret = -ENODEV;
 	struct fwnode_handle *iort_fwnode;
 
-	/*
-	 * If we already translated the fwspec there
-	 * is nothing left to do, return the iommu_ops.
-	 */
-	ops = iort_fwspec_iommu_ops(dev->iommu_fwspec);
-	if (ops)
-		return ops;
-
 	if (node) {
 		iort_fwnode = iort_get_fwnode(node);
 		if (!iort_fwnode)
@@ -735,6 +727,14 @@  const struct iommu_ops *iort_iommu_configure(struct device *dev)
 	u32 streamid = 0;
 	int err;
 
+	/*
+	 * If we already translated the fwspec there
+	 * is nothing left to do, return the iommu_ops.
+	 */
+	ops = iort_fwspec_iommu_ops(dev->iommu_fwspec);
+	if (ops)
+		return ops;
+
 	if (dev_is_pci(dev)) {
 		struct pci_bus *bus = to_pci_dev(dev)->bus;
 		u32 rid;