[v1] Skip subrange map tests on DWC iATU allocation failure

[PATCH 1/3] selftests: pci_endpoint: Skip subrange map test if iATU allocation fails

Posted by Christian Bruel 2 weeks, 5 days ago

Handle -ENOSPC error. If the number of available inbound ATU entries is
insufficient to map the subrange, skip the test instead of failing.

Link: https://lore.kernel.org/linux-pci/20260317152707.GA85951@bhelgaas/T/#m87e4c24173097a0ea70195b71aab294ad8d6c283
Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
---
 tools/testing/selftests/pci_endpoint/pci_endpoint_test.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
index c417fb3a198b2d92c3060938c23807cc8bea5573..8ea2fda4539d11eb22b22800a7cb8bbaa99c91ba 100644
--- a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
+++ b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
@@ -88,6 +88,8 @@ TEST_F(pci_ep_bar, BAR_SUBRANGE_TEST)
 		SKIP(return, "Subrange map is not supported");
 	if (ret == -ENOBUFS)
 		SKIP(return, "BAR is reserved");
+	if (ret == -ENOSPC)
+		SKIP(return, "Not enough ATU entries to allocate subrange");
 	EXPECT_FALSE(ret) TH_LOG("Test failed for BAR%d", variant->barno);
 }
 

-- 
2.34.1

Re: [PATCH 1/3] selftests: pci_endpoint: Skip subrange map test if iATU allocation fails

Posted by Koichiro Den 2 weeks, 4 days ago

On Wed, Mar 18, 2026 at 03:46:27PM +0100, Christian Bruel wrote:
> Handle -ENOSPC error. If the number of available inbound ATU entries is
> insufficient to map the subrange, skip the test instead of failing.
> 
> Link: https://lore.kernel.org/linux-pci/20260317152707.GA85951@bhelgaas/T/#m87e4c24173097a0ea70195b71aab294ad8d6c283
> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
> ---
>  tools/testing/selftests/pci_endpoint/pci_endpoint_test.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> index c417fb3a198b2d92c3060938c23807cc8bea5573..8ea2fda4539d11eb22b22800a7cb8bbaa99c91ba 100644
> --- a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> +++ b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> @@ -88,6 +88,8 @@ TEST_F(pci_ep_bar, BAR_SUBRANGE_TEST)
>  		SKIP(return, "Subrange map is not supported");
>  	if (ret == -ENOBUFS)
>  		SKIP(return, "BAR is reserved");
> +	if (ret == -ENOSPC)
> +		SKIP(return, "Not enough ATU entries to allocate subrange");

Thank you for handling this!

pci_endpoint_test_bar_subrange() can also return -ENOSPC locally:
https://github.com/torvalds/linux/blob/v7.0-rc4/drivers/misc/pci_endpoint_test.c#L538
While that is a different resource limit case, I think it would still be
reasonable to treat it as SKIP as well.

If you agree and keep your current approach, then I think the SKIP message
might be better phrased more generically, e.g. "Insufficient resources".

If you prefer to keep that local case as FAIL (or at least distinguish it
with a different SKIP message), that would likely require a bit more
changes overall. Note: Niklas' earlier feedback on the SKIP message would
still apply.

Best regards,
Koichiro

>  	EXPECT_FALSE(ret) TH_LOG("Test failed for BAR%d", variant->barno);
>  }
>  
> 
> -- 
> 2.34.1
>

Re: [PATCH 1/3] selftests: pci_endpoint: Skip subrange map test if iATU allocation fails

Posted by Christian Bruel 2 weeks, 3 days ago

Hello Koichiro, thank you for your comment

On 3/19/26 02:28, Koichiro Den wrote:
> On Wed, Mar 18, 2026 at 03:46:27PM +0100, Christian Bruel wrote:
>> Handle -ENOSPC error. If the number of available inbound ATU entries is
>> insufficient to map the subrange, skip the test instead of failing.
>>
>> Link: https://lore.kernel.org/linux-pci/20260317152707.GA85951@bhelgaas/T/#m87e4c24173097a0ea70195b71aab294ad8d6c283
>> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
>> ---
>>   tools/testing/selftests/pci_endpoint/pci_endpoint_test.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
>> index c417fb3a198b2d92c3060938c23807cc8bea5573..8ea2fda4539d11eb22b22800a7cb8bbaa99c91ba 100644
>> --- a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
>> +++ b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
>> @@ -88,6 +88,8 @@ TEST_F(pci_ep_bar, BAR_SUBRANGE_TEST)
>>   		SKIP(return, "Subrange map is not supported");
>>   	if (ret == -ENOBUFS)
>>   		SKIP(return, "BAR is reserved");
>> +	if (ret == -ENOSPC)
>> +		SKIP(return, "Not enough ATU entries to allocate subrange");
> 
> Thank you for handling this!
> 
> pci_endpoint_test_bar_subrange() can also return -ENOSPC locally:
> https://github.com/torvalds/linux/blob/v7.0-rc4/drivers/misc/pci_endpoint_test.c#L538
> While that is a different resource limit case, I think it would still be
> reasonable to treat it as SKIP as well.

Regarding Niklas's feedback to use the local EINVAL instead of ENOSPC in 
pci_endpoint_test_bar_subrange(), I prefer to leave this for you to 
handle. That will cover this case.

> 
> If you agree and keep your current approach, then I think the SKIP message
> might be better phrased more generically, e.g. "Insufficient resources".

OK I agree, the error message should be less specific to DWC 
terminology, even though this case can currently only occur on it.

> 
> If you prefer to keep that local case as FAIL (or at least distinguish it
> with a different SKIP message), that would likely require a bit more
> changes overall. Note: Niklas' earlier feedback on the SKIP message would
> still apply.

OK, as Niklas also suggested, I will not set an additional local bit 
besides the fail bit. The question is whether we should name it SKIP or 
NOSPC. I slightly prefer NOSPC, as this is what is used in the selftest 
to indicate skipping.

thank you

Christian

> 
> Best regards,
> Koichiro
> 
>>   	EXPECT_FALSE(ret) TH_LOG("Test failed for BAR%d", variant->barno);
>>   }
>>   
>>
>> -- 
>> 2.34.1
>>

Re: [PATCH 1/3] selftests: pci_endpoint: Skip subrange map test if iATU allocation fails

Posted by Koichiro Den 2 weeks, 3 days ago

On Fri, Mar 20, 2026 at 11:04:28AM +0100, Christian Bruel wrote:
> Hello Koichiro, thank you for your comment
> 
> On 3/19/26 02:28, Koichiro Den wrote:
> > On Wed, Mar 18, 2026 at 03:46:27PM +0100, Christian Bruel wrote:
> > > Handle -ENOSPC error. If the number of available inbound ATU entries is
> > > insufficient to map the subrange, skip the test instead of failing.
> > > 
> > > Link: https://lore.kernel.org/linux-pci/20260317152707.GA85951@bhelgaas/T/#m87e4c24173097a0ea70195b71aab294ad8d6c283
> > > Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
> > > ---
> > >   tools/testing/selftests/pci_endpoint/pci_endpoint_test.c | 2 ++
> > >   1 file changed, 2 insertions(+)
> > > 
> > > diff --git a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > > index c417fb3a198b2d92c3060938c23807cc8bea5573..8ea2fda4539d11eb22b22800a7cb8bbaa99c91ba 100644
> > > --- a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > > +++ b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > > @@ -88,6 +88,8 @@ TEST_F(pci_ep_bar, BAR_SUBRANGE_TEST)
> > >   		SKIP(return, "Subrange map is not supported");
> > >   	if (ret == -ENOBUFS)
> > >   		SKIP(return, "BAR is reserved");
> > > +	if (ret == -ENOSPC)
> > > +		SKIP(return, "Not enough ATU entries to allocate subrange");
> > 
> > Thank you for handling this!
> > 
> > pci_endpoint_test_bar_subrange() can also return -ENOSPC locally:
> > https://github.com/torvalds/linux/blob/v7.0-rc4/drivers/misc/pci_endpoint_test.c#L538
> > While that is a different resource limit case, I think it would still be
> > reasonable to treat it as SKIP as well.
> 
> Regarding Niklas's feedback to use the local EINVAL instead of ENOSPC in
> pci_endpoint_test_bar_subrange(), I prefer to leave this for you to handle.
> That will cover this case.

So could you consider the following tiny patch as a prerequisite for your
series?
https://lore.kernel.org/linux-pci/20260320140139.2415480-1-den@valinux.co.jp/

> 
> > 
> > If you agree and keep your current approach, then I think the SKIP message
> > might be better phrased more generically, e.g. "Insufficient resources".
> 
> OK I agree, the error message should be less specific to DWC terminology,
> even though this case can currently only occur on it.

Yes, I agree. As mentioned in my reply to Niklas, the other -ENOSPC is better
replaced with -EINVAL, so I just submitted a tiny patch. That concern should be
resolved.

> 
> > 
> > If you prefer to keep that local case as FAIL (or at least distinguish it
> > with a different SKIP message), that would likely require a bit more
> > changes overall. Note: Niklas' earlier feedback on the SKIP message would
> > still apply.
> 
> OK, as Niklas also suggested, I will not set an additional local bit besides
> the fail bit. The question is whether we should name it SKIP or NOSPC. I
> slightly prefer NOSPC, as this is what is used in the selftest to indicate
> skipping.

Personally, Niklas' "errno in struct pci_epf_test_reg" idea sounds the best
among the options discussed so far.

Best regards,
Koichiro

> 
> thank you
> 
> Christian
> 
> > 
> > Best regards,
> > Koichiro
> > 
> > >   	EXPECT_FALSE(ret) TH_LOG("Test failed for BAR%d", variant->barno);
> > >   }
> > > 
> > > -- 
> > > 2.34.1
> > > 
>

Re: [PATCH 1/3] selftests: pci_endpoint: Skip subrange map test if iATU allocation fails

Posted by Christian Bruel 2 weeks, 3 days ago


On 3/20/26 15:05, Koichiro Den wrote:
> On Fri, Mar 20, 2026 at 11:04:28AM +0100, Christian Bruel wrote:
>> Hello Koichiro, thank you for your comment
>>
>> On 3/19/26 02:28, Koichiro Den wrote:
>>> On Wed, Mar 18, 2026 at 03:46:27PM +0100, Christian Bruel wrote:
>>>> Handle -ENOSPC error. If the number of available inbound ATU entries is
>>>> insufficient to map the subrange, skip the test instead of failing.
>>>>
>>>> Link: https://lore.kernel.org/linux-pci/20260317152707.GA85951@bhelgaas/T/#m87e4c24173097a0ea70195b71aab294ad8d6c283
>>>> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
>>>> ---
>>>>    tools/testing/selftests/pci_endpoint/pci_endpoint_test.c | 2 ++
>>>>    1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
>>>> index c417fb3a198b2d92c3060938c23807cc8bea5573..8ea2fda4539d11eb22b22800a7cb8bbaa99c91ba 100644
>>>> --- a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
>>>> +++ b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
>>>> @@ -88,6 +88,8 @@ TEST_F(pci_ep_bar, BAR_SUBRANGE_TEST)
>>>>    		SKIP(return, "Subrange map is not supported");
>>>>    	if (ret == -ENOBUFS)
>>>>    		SKIP(return, "BAR is reserved");
>>>> +	if (ret == -ENOSPC)
>>>> +		SKIP(return, "Not enough ATU entries to allocate subrange");
>>>
>>> Thank you for handling this!
>>>
>>> pci_endpoint_test_bar_subrange() can also return -ENOSPC locally:
>>> https://github.com/torvalds/linux/blob/v7.0-rc4/drivers/misc/pci_endpoint_test.c#L538
>>> While that is a different resource limit case, I think it would still be
>>> reasonable to treat it as SKIP as well.
>>
>> Regarding Niklas's feedback to use the local EINVAL instead of ENOSPC in
>> pci_endpoint_test_bar_subrange(), I prefer to leave this for you to handle.
>> That will cover this case.
> 
> So could you consider the following tiny patch as a prerequisite for your
> series?
> https://lore.kernel.org/linux-pci/20260320140139.2415480-1-den@valinux.co.jp/

sure, thank you

> 
>>
>>>
>>> If you agree and keep your current approach, then I think the SKIP message
>>> might be better phrased more generically, e.g. "Insufficient resources".
>>
>> OK I agree, the error message should be less specific to DWC terminology,
>> even though this case can currently only occur on it.
> 
> Yes, I agree. As mentioned in my reply to Niklas, the other -ENOSPC is better
> replaced with -EINVAL, so I just submitted a tiny patch. That concern should be
> resolved.
> 
>>
>>>
>>> If you prefer to keep that local case as FAIL (or at least distinguish it
>>> with a different SKIP message), that would likely require a bit more
>>> changes overall. Note: Niklas' earlier feedback on the SKIP message would
>>> still apply.
>>
>> OK, as Niklas also suggested, I will not set an additional local bit besides
>> the fail bit. The question is whether we should name it SKIP or NOSPC. I
>> slightly prefer NOSPC, as this is what is used in the selftest to indicate
>> skipping.
> 
> Personally, Niklas' "errno in struct pci_epf_test_reg" idea sounds the best
> among the options discussed so far.

It is a good solution but does not match very well with the other 
existing API (See the STATUS_SRC/DST_ADDR_INVALID bits). Thus, we will 
keep the existing method of reporting errors using a second bit 
alongside the FAIL bit.


> 
> Best regards,
> Koichiro
> 
>>
>> thank you
>>
>> Christian
>>
>>>
>>> Best regards,
>>> Koichiro
>>>
>>>>    	EXPECT_FALSE(ret) TH_LOG("Test failed for BAR%d", variant->barno);
>>>>    }
>>>>
>>>> -- 
>>>> 2.34.1
>>>>
>>

Re: [PATCH 1/3] selftests: pci_endpoint: Skip subrange map test if iATU allocation fails

Posted by Koichiro Den 2 weeks, 3 days ago

On Fri, Mar 20, 2026 at 03:19:15PM +0100, Christian Bruel wrote:
> 
> 
> On 3/20/26 15:05, Koichiro Den wrote:
> > On Fri, Mar 20, 2026 at 11:04:28AM +0100, Christian Bruel wrote:
> > > Hello Koichiro, thank you for your comment
> > > 
> > > On 3/19/26 02:28, Koichiro Den wrote:
> > > > On Wed, Mar 18, 2026 at 03:46:27PM +0100, Christian Bruel wrote:
> > > > > Handle -ENOSPC error. If the number of available inbound ATU entries is
> > > > > insufficient to map the subrange, skip the test instead of failing.
> > > > > 
> > > > > Link: https://lore.kernel.org/linux-pci/20260317152707.GA85951@bhelgaas/T/#m87e4c24173097a0ea70195b71aab294ad8d6c283
> > > > > Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
> > > > > ---
> > > > >    tools/testing/selftests/pci_endpoint/pci_endpoint_test.c | 2 ++
> > > > >    1 file changed, 2 insertions(+)
> > > > > 
> > > > > diff --git a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > > > > index c417fb3a198b2d92c3060938c23807cc8bea5573..8ea2fda4539d11eb22b22800a7cb8bbaa99c91ba 100644
> > > > > --- a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > > > > +++ b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > > > > @@ -88,6 +88,8 @@ TEST_F(pci_ep_bar, BAR_SUBRANGE_TEST)
> > > > >    		SKIP(return, "Subrange map is not supported");
> > > > >    	if (ret == -ENOBUFS)
> > > > >    		SKIP(return, "BAR is reserved");
> > > > > +	if (ret == -ENOSPC)
> > > > > +		SKIP(return, "Not enough ATU entries to allocate subrange");
> > > > 
> > > > Thank you for handling this!
> > > > 
> > > > pci_endpoint_test_bar_subrange() can also return -ENOSPC locally:
> > > > https://github.com/torvalds/linux/blob/v7.0-rc4/drivers/misc/pci_endpoint_test.c#L538
> > > > While that is a different resource limit case, I think it would still be
> > > > reasonable to treat it as SKIP as well.
> > > 
> > > Regarding Niklas's feedback to use the local EINVAL instead of ENOSPC in
> > > pci_endpoint_test_bar_subrange(), I prefer to leave this for you to handle.
> > > That will cover this case.
> > 
> > So could you consider the following tiny patch as a prerequisite for your
> > series?
> > https://lore.kernel.org/linux-pci/20260320140139.2415480-1-den@valinux.co.jp/
> 
> sure, thank you
> 
> > 
> > > 
> > > > 
> > > > If you agree and keep your current approach, then I think the SKIP message
> > > > might be better phrased more generically, e.g. "Insufficient resources".
> > > 
> > > OK I agree, the error message should be less specific to DWC terminology,
> > > even though this case can currently only occur on it.
> > 
> > Yes, I agree. As mentioned in my reply to Niklas, the other -ENOSPC is better
> > replaced with -EINVAL, so I just submitted a tiny patch. That concern should be
> > resolved.
> > 
> > > 
> > > > 
> > > > If you prefer to keep that local case as FAIL (or at least distinguish it
> > > > with a different SKIP message), that would likely require a bit more
> > > > changes overall. Note: Niklas' earlier feedback on the SKIP message would
> > > > still apply.
> > > 
> > > OK, as Niklas also suggested, I will not set an additional local bit besides
> > > the fail bit. The question is whether we should name it SKIP or NOSPC. I
> > > slightly prefer NOSPC, as this is what is used in the selftest to indicate
> > > skipping.
> > 
> > Personally, Niklas' "errno in struct pci_epf_test_reg" idea sounds the best
> > among the options discussed so far.
> 
> It is a good solution but does not match very well with the other existing
> API (See the STATUS_SRC/DST_ADDR_INVALID bits). Thus, we will keep the
> existing method of reporting errors using a second bit alongside the FAIL
> bit.

Understood. Thank you!

Koichiro

> 
> 
> > 
> > Best regards,
> > Koichiro
> > 
> > > 
> > > thank you
> > > 
> > > Christian
> > > 
> > > > 
> > > > Best regards,
> > > > Koichiro
> > > > 
> > > > >    	EXPECT_FALSE(ret) TH_LOG("Test failed for BAR%d", variant->barno);
> > > > >    }
> > > > > 
> > > > > -- 
> > > > > 2.34.1
> > > > > 
> > > 
>

Re: [PATCH 1/3] selftests: pci_endpoint: Skip subrange map test if iATU allocation fails

Posted by Niklas Cassel 2 weeks, 4 days ago

On Thu, Mar 19, 2026 at 10:28:41AM +0900, Koichiro Den wrote:
> On Wed, Mar 18, 2026 at 03:46:27PM +0100, Christian Bruel wrote:
> > Handle -ENOSPC error. If the number of available inbound ATU entries is
> > insufficient to map the subrange, skip the test instead of failing.
> >
> > Link: https://lore.kernel.org/linux-pci/20260317152707.GA85951@bhelgaas/T/#m87e4c24173097a0ea70195b71aab294ad8d6c283
> > Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
> > ---
> >  tools/testing/selftests/pci_endpoint/pci_endpoint_test.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > index c417fb3a198b2d92c3060938c23807cc8bea5573..8ea2fda4539d11eb22b22800a7cb8bbaa99c91ba 100644
> > --- a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > +++ b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > @@ -88,6 +88,8 @@ TEST_F(pci_ep_bar, BAR_SUBRANGE_TEST)
> >		SKIP(return, "Subrange map is not supported");
> >	if (ret == -ENOBUFS)
> >		SKIP(return, "BAR is reserved");
> > +	if (ret == -ENOSPC)
> > +		SKIP(return, "Not enough ATU entries to allocate subrange");
>
> Thank you for handling this!
>
> pci_endpoint_test_bar_subrange() can also return -ENOSPC locally:
> https://github.com/torvalds/linux/blob/v7.0-rc4/drivers/misc/pci_endpoint_test.c#L538
> While that is a different resource limit case, I think it would still be
> reasonable to treat it as SKIP as well.

	sub_size = bar_size / nsub;
	if (sub_size < sizeof(u32)) {
		ret = -ENOSPC;
		goto out_clear;
	}

What is this test for anyway?

If sub_size < 4 ?
 return -ENOSPACE ?

ENOSPC seem like a weird return for this.

Wouldn't EINVAL be a better return code for this?


Kind regards,
Niklas

Re: [PATCH 1/3] selftests: pci_endpoint: Skip subrange map test if iATU allocation fails

Posted by Koichiro Den 2 weeks, 3 days ago

On Thu, Mar 19, 2026 at 09:47:15AM +0100, Niklas Cassel wrote:
> On Thu, Mar 19, 2026 at 10:28:41AM +0900, Koichiro Den wrote:
> > On Wed, Mar 18, 2026 at 03:46:27PM +0100, Christian Bruel wrote:
> > > Handle -ENOSPC error. If the number of available inbound ATU entries is
> > > insufficient to map the subrange, skip the test instead of failing.
> > >
> > > Link: https://lore.kernel.org/linux-pci/20260317152707.GA85951@bhelgaas/T/#m87e4c24173097a0ea70195b71aab294ad8d6c283
> > > Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
> > > ---
> > >  tools/testing/selftests/pci_endpoint/pci_endpoint_test.c | 2 ++
> > >  1 file changed, 2 insertions(+)
> > >
> > > diff --git a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > > index c417fb3a198b2d92c3060938c23807cc8bea5573..8ea2fda4539d11eb22b22800a7cb8bbaa99c91ba 100644
> > > --- a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > > +++ b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> > > @@ -88,6 +88,8 @@ TEST_F(pci_ep_bar, BAR_SUBRANGE_TEST)
> > >		SKIP(return, "Subrange map is not supported");
> > >	if (ret == -ENOBUFS)
> > >		SKIP(return, "BAR is reserved");
> > > +	if (ret == -ENOSPC)
> > > +		SKIP(return, "Not enough ATU entries to allocate subrange");
> >
> > Thank you for handling this!
> >
> > pci_endpoint_test_bar_subrange() can also return -ENOSPC locally:
> > https://github.com/torvalds/linux/blob/v7.0-rc4/drivers/misc/pci_endpoint_test.c#L538
> > While that is a different resource limit case, I think it would still be
> > reasonable to treat it as SKIP as well.
> 
> 	sub_size = bar_size / nsub;
> 	if (sub_size < sizeof(u32)) {
> 		ret = -ENOSPC;
> 		goto out_clear;
> 	}
> 
> What is this test for anyway?
> 
> If sub_size < 4 ?
>  return -ENOSPACE ?
> 
> ENOSPC seem like a weird return for this.
> 
> Wouldn't EINVAL be a better return code for this?

Thanks, good point.

It is to ensure that each subrange is large enough for 32-bit accesses.
I must have used -ENOSPC here thinking of it as "no space for subrange
mapping".

However, subranges smaller than 32-bit do not make sense for this test, and
-EINVAL seems more appropriate here as you pointed out. Also, the PCIe spec
defines the minimum Memory Space BAR size as 128 bytes, so subranges
smaller than that would not normally exist in practice, which also aligns
better with -EINVAL than -ENOSPC.

That would keep -ENOSPC reserved for actual resource limitations (i.e.
inbound regions limitation).

Best regards,
Koichiro

> 
> 
> Kind regards,
> Niklas

Re: [PATCH 1/3] selftests: pci_endpoint: Skip subrange map test if iATU allocation fails

Posted by Niklas Cassel 2 weeks, 5 days ago

On Wed, Mar 18, 2026 at 03:46:27PM +0100, Christian Bruel wrote:
> Handle -ENOSPC error. If the number of available inbound ATU entries is
> insufficient to map the subrange, skip the test instead of failing.
> 
> Link: https://lore.kernel.org/linux-pci/20260317152707.GA85951@bhelgaas/T/#m87e4c24173097a0ea70195b71aab294ad8d6c283

I would drop the link, it does not really add any value.

> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
> ---
>  tools/testing/selftests/pci_endpoint/pci_endpoint_test.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> index c417fb3a198b2d92c3060938c23807cc8bea5573..8ea2fda4539d11eb22b22800a7cb8bbaa99c91ba 100644
> --- a/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> +++ b/tools/testing/selftests/pci_endpoint/pci_endpoint_test.c
> @@ -88,6 +88,8 @@ TEST_F(pci_ep_bar, BAR_SUBRANGE_TEST)
>  		SKIP(return, "Subrange map is not supported");
>  	if (ret == -ENOBUFS)
>  		SKIP(return, "BAR is reserved");
> +	if (ret == -ENOSPC)
> +		SKIP(return, "Not enough ATU entries to allocate subrange");

ATU is a DWC specific term.
I would use "inbound windows" instead.
E.g. "Not enough inbound windows to allocate subrange"


Considering that the selftests is highest up the stack, I would put this
patch as 3/3 and not 1/3.


Kind regards,
Niklas