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[PATCH v2] PCI: Use downstream bridges for distributing resources

Kai-Heng Feng posted 1 patch 1 year ago 
drivers/pci/setup-bus.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
[PATCH v2] PCI: Use downstream bridges for distributing resources
Posted by Kai-Heng Feng 1 year ago 
Commit 7180c1d08639 ("PCI: Distribute available resources for root
buses, too") breaks BAR assignment on some devcies:
[   10.021193] pci 0006:03:00.0: BAR 0 [mem 0x6300c0000000-0x6300c1ffffff 64bit pref]: assigned
[   10.029880] pci 0006:03:00.1: BAR 0 [mem 0x6300c2000000-0x6300c3ffffff 64bit pref]: assigned
[   10.038561] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: can't assign; no space
[   10.047191] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: failed to assign
[   10.055285] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: can't assign; no space
[   10.064180] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: failed to assign
[   10.072543] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: can't assign; no space
[   10.081437] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: failed to assign

The apertures of domain 0006 before the commit:
6300c0000000-63ffffffffff : PCI Bus 0006:00
  6300c0000000-6300c9ffffff : PCI Bus 0006:01
    6300c0000000-6300c9ffffff : PCI Bus 0006:02
      6300c0000000-6300c8ffffff : PCI Bus 0006:03
        6300c0000000-6300c1ffffff : 0006:03:00.0
          6300c0000000-6300c1ffffff : mlx5_core
        6300c2000000-6300c3ffffff : 0006:03:00.1
          6300c2000000-6300c3ffffff : mlx5_core
        6300c4000000-6300c47fffff : 0006:03:00.2
        6300c4800000-6300c67fffff : 0006:03:00.0
        6300c6800000-6300c87fffff : 0006:03:00.1
      6300c9000000-6300c9bfffff : PCI Bus 0006:04
        6300c9000000-6300c9bfffff : PCI Bus 0006:05
          6300c9000000-6300c91fffff : PCI Bus 0006:06
          6300c9200000-6300c93fffff : PCI Bus 0006:07
          6300c9400000-6300c95fffff : PCI Bus 0006:08
          6300c9600000-6300c97fffff : PCI Bus 0006:09

After the commit:
6300c0000000-63ffffffffff : PCI Bus 0006:00
  6300c0000000-6300c9ffffff : PCI Bus 0006:01
    6300c0000000-6300c9ffffff : PCI Bus 0006:02
      6300c0000000-6300c43fffff : PCI Bus 0006:03
        6300c0000000-6300c1ffffff : 0006:03:00.0
          6300c0000000-6300c1ffffff : mlx5_core
        6300c2000000-6300c3ffffff : 0006:03:00.1
          6300c2000000-6300c3ffffff : mlx5_core
      6300c4400000-6300c4dfffff : PCI Bus 0006:04
        6300c4400000-6300c4dfffff : PCI Bus 0006:05
          6300c4400000-6300c45fffff : PCI Bus 0006:06
          6300c4600000-6300c47fffff : PCI Bus 0006:07
          6300c4800000-6300c49fffff : PCI Bus 0006:08
          6300c4a00000-6300c4bfffff : PCI Bus 0006:09

We can see that the window of 0006:03 gets shrunken too much and 0006:04
eats away the window for 0006:03:00.2.

The offending commit distributes the upstream bridge's resources
multiple times to every downstream bridges, hence makes the aperture
smaller than desired because calculation of io_per_b, mmio_per_b and
mmio_pref_per_b becomes incorrect.

Instead, distributing downstream bridges' own resources to resolve the
issue.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=219540
Cc: Carol Soto <csoto@nvidia.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Chris Chiu <chris.chiu@canonical.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com>
Fixes: 7180c1d08639 ("PCI: Distribute available resources for root buses, too")
Signed-off-by: Kai-Heng Feng <kaihengf@nvidia.com>
---
 drivers/pci/setup-bus.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 23082bc0ca37..a6e653a4f5b1 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -2105,8 +2105,7 @@ pci_root_bus_distribute_available_resources(struct pci_bus *bus,
 		 * in case of root bus.
 		 */
 		if (bridge && pci_bridge_resources_not_assigned(dev))
-			pci_bridge_distribute_available_resources(bridge,
-								  add_list);
+			pci_bridge_distribute_available_resources(dev, add_list);
 		else
 			pci_root_bus_distribute_available_resources(b, add_list);
 	}
-- 
2.47.0
Re: [PATCH v2] PCI: Use downstream bridges for distributing resources
Posted by Bjorn Helgaas 10 months, 1 week ago 
On Wed, Dec 04, 2024 at 10:24:57AM +0800, Kai-Heng Feng wrote:
> Commit 7180c1d08639 ("PCI: Distribute available resources for root
> buses, too") breaks BAR assignment on some devcies:
> [   10.021193] pci 0006:03:00.0: BAR 0 [mem 0x6300c0000000-0x6300c1ffffff 64bit pref]: assigned
> [   10.029880] pci 0006:03:00.1: BAR 0 [mem 0x6300c2000000-0x6300c3ffffff 64bit pref]: assigned
> [   10.038561] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: can't assign; no space
> [   10.047191] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: failed to assign
> [   10.055285] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: can't assign; no space
> [   10.064180] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: failed to assign
> [   10.072543] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: can't assign; no space
> [   10.081437] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: failed to assign
> 
> The apertures of domain 0006 before the commit:
> 6300c0000000-63ffffffffff : PCI Bus 0006:00
>   6300c0000000-6300c9ffffff : PCI Bus 0006:01
>     6300c0000000-6300c9ffffff : PCI Bus 0006:02
>       6300c0000000-6300c8ffffff : PCI Bus 0006:03
>         6300c0000000-6300c1ffffff : 0006:03:00.0
>           6300c0000000-6300c1ffffff : mlx5_core
>         6300c2000000-6300c3ffffff : 0006:03:00.1
>           6300c2000000-6300c3ffffff : mlx5_core
>         6300c4000000-6300c47fffff : 0006:03:00.2
>         6300c4800000-6300c67fffff : 0006:03:00.0
>         6300c6800000-6300c87fffff : 0006:03:00.1
>       6300c9000000-6300c9bfffff : PCI Bus 0006:04
>         6300c9000000-6300c9bfffff : PCI Bus 0006:05
>           6300c9000000-6300c91fffff : PCI Bus 0006:06
>           6300c9200000-6300c93fffff : PCI Bus 0006:07
>           6300c9400000-6300c95fffff : PCI Bus 0006:08
>           6300c9600000-6300c97fffff : PCI Bus 0006:09
> 
> After the commit:
> 6300c0000000-63ffffffffff : PCI Bus 0006:00
>   6300c0000000-6300c9ffffff : PCI Bus 0006:01
>     6300c0000000-6300c9ffffff : PCI Bus 0006:02
>       6300c0000000-6300c43fffff : PCI Bus 0006:03
>         6300c0000000-6300c1ffffff : 0006:03:00.0
>           6300c0000000-6300c1ffffff : mlx5_core
>         6300c2000000-6300c3ffffff : 0006:03:00.1
>           6300c2000000-6300c3ffffff : mlx5_core
>       6300c4400000-6300c4dfffff : PCI Bus 0006:04
>         6300c4400000-6300c4dfffff : PCI Bus 0006:05
>           6300c4400000-6300c45fffff : PCI Bus 0006:06
>           6300c4600000-6300c47fffff : PCI Bus 0006:07
>           6300c4800000-6300c49fffff : PCI Bus 0006:08
>           6300c4a00000-6300c4bfffff : PCI Bus 0006:09
> 
> We can see that the window of 0006:03 gets shrunken too much and 0006:04
> eats away the window for 0006:03:00.2.
> 
> The offending commit distributes the upstream bridge's resources
> multiple times to every downstream bridges, hence makes the aperture
> smaller than desired because calculation of io_per_b, mmio_per_b and
> mmio_pref_per_b becomes incorrect.
> 
> Instead, distributing downstream bridges' own resources to resolve the
> issue.
> 
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=219540
> Cc: Carol Soto <csoto@nvidia.com>
> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Cc: Chris Chiu <chris.chiu@canonical.com>
> Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
> Tested-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com>
> Fixes: 7180c1d08639 ("PCI: Distribute available resources for root buses, too")
> Signed-off-by: Kai-Heng Feng <kaihengf@nvidia.com>

Applied with Mika's Reviewed-by to pci/resource for v6.15, thanks!

> ---
>  drivers/pci/setup-bus.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 23082bc0ca37..a6e653a4f5b1 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -2105,8 +2105,7 @@ pci_root_bus_distribute_available_resources(struct pci_bus *bus,
>  		 * in case of root bus.
>  		 */
>  		if (bridge && pci_bridge_resources_not_assigned(dev))
> -			pci_bridge_distribute_available_resources(bridge,
> -								  add_list);
> +			pci_bridge_distribute_available_resources(dev, add_list);
>  		else
>  			pci_root_bus_distribute_available_resources(b, add_list);
>  	}
> -- 
> 2.47.0
>
Re: [PATCH v2] PCI: Use downstream bridges for distributing resources
Posted by Mika Westerberg 1 year ago 
On Wed, Dec 04, 2024 at 10:24:57AM +0800, Kai-Heng Feng wrote:
> Commit 7180c1d08639 ("PCI: Distribute available resources for root
> buses, too") breaks BAR assignment on some devcies:
> [   10.021193] pci 0006:03:00.0: BAR 0 [mem 0x6300c0000000-0x6300c1ffffff 64bit pref]: assigned
> [   10.029880] pci 0006:03:00.1: BAR 0 [mem 0x6300c2000000-0x6300c3ffffff 64bit pref]: assigned
> [   10.038561] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: can't assign; no space
> [   10.047191] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: failed to assign
> [   10.055285] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: can't assign; no space
> [   10.064180] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: failed to assign
> [   10.072543] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: can't assign; no space
> [   10.081437] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: failed to assign
> 
> The apertures of domain 0006 before the commit:
> 6300c0000000-63ffffffffff : PCI Bus 0006:00
>   6300c0000000-6300c9ffffff : PCI Bus 0006:01
>     6300c0000000-6300c9ffffff : PCI Bus 0006:02
>       6300c0000000-6300c8ffffff : PCI Bus 0006:03
>         6300c0000000-6300c1ffffff : 0006:03:00.0
>           6300c0000000-6300c1ffffff : mlx5_core
>         6300c2000000-6300c3ffffff : 0006:03:00.1
>           6300c2000000-6300c3ffffff : mlx5_core
>         6300c4000000-6300c47fffff : 0006:03:00.2
>         6300c4800000-6300c67fffff : 0006:03:00.0
>         6300c6800000-6300c87fffff : 0006:03:00.1
>       6300c9000000-6300c9bfffff : PCI Bus 0006:04
>         6300c9000000-6300c9bfffff : PCI Bus 0006:05
>           6300c9000000-6300c91fffff : PCI Bus 0006:06
>           6300c9200000-6300c93fffff : PCI Bus 0006:07
>           6300c9400000-6300c95fffff : PCI Bus 0006:08
>           6300c9600000-6300c97fffff : PCI Bus 0006:09
> 
> After the commit:
> 6300c0000000-63ffffffffff : PCI Bus 0006:00
>   6300c0000000-6300c9ffffff : PCI Bus 0006:01
>     6300c0000000-6300c9ffffff : PCI Bus 0006:02
>       6300c0000000-6300c43fffff : PCI Bus 0006:03
>         6300c0000000-6300c1ffffff : 0006:03:00.0
>           6300c0000000-6300c1ffffff : mlx5_core
>         6300c2000000-6300c3ffffff : 0006:03:00.1
>           6300c2000000-6300c3ffffff : mlx5_core
>       6300c4400000-6300c4dfffff : PCI Bus 0006:04
>         6300c4400000-6300c4dfffff : PCI Bus 0006:05
>           6300c4400000-6300c45fffff : PCI Bus 0006:06
>           6300c4600000-6300c47fffff : PCI Bus 0006:07
>           6300c4800000-6300c49fffff : PCI Bus 0006:08
>           6300c4a00000-6300c4bfffff : PCI Bus 0006:09
> 
> We can see that the window of 0006:03 gets shrunken too much and 0006:04
> eats away the window for 0006:03:00.2.
> 
> The offending commit distributes the upstream bridge's resources
> multiple times to every downstream bridges, hence makes the aperture
> smaller than desired because calculation of io_per_b, mmio_per_b and
> mmio_pref_per_b becomes incorrect.
> 
> Instead, distributing downstream bridges' own resources to resolve the
> issue.
> 
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=219540
> Cc: Carol Soto <csoto@nvidia.com>
> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Cc: Chris Chiu <chris.chiu@canonical.com>
> Cc: Mika Westerberg <mika.westerberg@linux.intel.com>

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Re: [PATCH v2] PCI: Use downstream bridges for distributing resources
Posted by Kai-Heng Feng 1 year ago 
Hi Bjorn,

On 2024/12/4 1:48 PM, Mika Westerberg wrote:
> External email: Use caution opening links or attachments
> 
> 
> On Wed, Dec 04, 2024 at 10:24:57AM +0800, Kai-Heng Feng wrote:
>> Commit 7180c1d08639 ("PCI: Distribute available resources for root
>> buses, too") breaks BAR assignment on some devcies:
>> [   10.021193] pci 0006:03:00.0: BAR 0 [mem 0x6300c0000000-0x6300c1ffffff 64bit pref]: assigned
>> [   10.029880] pci 0006:03:00.1: BAR 0 [mem 0x6300c2000000-0x6300c3ffffff 64bit pref]: assigned
>> [   10.038561] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: can't assign; no space
>> [   10.047191] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: failed to assign
>> [   10.055285] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: can't assign; no space
>> [   10.064180] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: failed to assign
>> [   10.072543] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: can't assign; no space
>> [   10.081437] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: failed to assign
>>
>> The apertures of domain 0006 before the commit:
>> 6300c0000000-63ffffffffff : PCI Bus 0006:00
>>    6300c0000000-6300c9ffffff : PCI Bus 0006:01
>>      6300c0000000-6300c9ffffff : PCI Bus 0006:02
>>        6300c0000000-6300c8ffffff : PCI Bus 0006:03
>>          6300c0000000-6300c1ffffff : 0006:03:00.0
>>            6300c0000000-6300c1ffffff : mlx5_core
>>          6300c2000000-6300c3ffffff : 0006:03:00.1
>>            6300c2000000-6300c3ffffff : mlx5_core
>>          6300c4000000-6300c47fffff : 0006:03:00.2
>>          6300c4800000-6300c67fffff : 0006:03:00.0
>>          6300c6800000-6300c87fffff : 0006:03:00.1
>>        6300c9000000-6300c9bfffff : PCI Bus 0006:04
>>          6300c9000000-6300c9bfffff : PCI Bus 0006:05
>>            6300c9000000-6300c91fffff : PCI Bus 0006:06
>>            6300c9200000-6300c93fffff : PCI Bus 0006:07
>>            6300c9400000-6300c95fffff : PCI Bus 0006:08
>>            6300c9600000-6300c97fffff : PCI Bus 0006:09
>>
>> After the commit:
>> 6300c0000000-63ffffffffff : PCI Bus 0006:00
>>    6300c0000000-6300c9ffffff : PCI Bus 0006:01
>>      6300c0000000-6300c9ffffff : PCI Bus 0006:02
>>        6300c0000000-6300c43fffff : PCI Bus 0006:03
>>          6300c0000000-6300c1ffffff : 0006:03:00.0
>>            6300c0000000-6300c1ffffff : mlx5_core
>>          6300c2000000-6300c3ffffff : 0006:03:00.1
>>            6300c2000000-6300c3ffffff : mlx5_core
>>        6300c4400000-6300c4dfffff : PCI Bus 0006:04
>>          6300c4400000-6300c4dfffff : PCI Bus 0006:05
>>            6300c4400000-6300c45fffff : PCI Bus 0006:06
>>            6300c4600000-6300c47fffff : PCI Bus 0006:07
>>            6300c4800000-6300c49fffff : PCI Bus 0006:08
>>            6300c4a00000-6300c4bfffff : PCI Bus 0006:09
>>
>> We can see that the window of 0006:03 gets shrunken too much and 0006:04
>> eats away the window for 0006:03:00.2.
>>
>> The offending commit distributes the upstream bridge's resources
>> multiple times to every downstream bridges, hence makes the aperture
>> smaller than desired because calculation of io_per_b, mmio_per_b and
>> mmio_pref_per_b becomes incorrect.
>>
>> Instead, distributing downstream bridges' own resources to resolve the
>> issue.
>>
>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=219540
>> Cc: Carol Soto <csoto@nvidia.com>
>> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>> Cc: Chris Chiu <chris.chiu@canonical.com>
>> Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
> 
> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Is it possible to pickup this up in 6.13 window?

Kai-Heng
Re: [PATCH v2] PCI: Use downstream bridges for distributing resources
Posted by Kai-Heng Feng 11 months ago 

On 2024/12/18 7:12 PM, Kai-Heng Feng wrote:
> Hi Bjorn,
> 
> On 2024/12/4 1:48 PM, Mika Westerberg wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> On Wed, Dec 04, 2024 at 10:24:57AM +0800, Kai-Heng Feng wrote:
>>> Commit 7180c1d08639 ("PCI: Distribute available resources for root
>>> buses, too") breaks BAR assignment on some devcies:
>>> [   10.021193] pci 0006:03:00.0: BAR 0 [mem 0x6300c0000000-0x6300c1ffffff 
>>> 64bit pref]: assigned
>>> [   10.029880] pci 0006:03:00.1: BAR 0 [mem 0x6300c2000000-0x6300c3ffffff 
>>> 64bit pref]: assigned
>>> [   10.038561] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: 
>>> can't assign; no space
>>> [   10.047191] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: 
>>> failed to assign
>>> [   10.055285] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: 
>>> can't assign; no space
>>> [   10.064180] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: 
>>> failed to assign
>>> [   10.072543] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: 
>>> can't assign; no space
>>> [   10.081437] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: 
>>> failed to assign
>>>
>>> The apertures of domain 0006 before the commit:
>>> 6300c0000000-63ffffffffff : PCI Bus 0006:00
>>>    6300c0000000-6300c9ffffff : PCI Bus 0006:01
>>>      6300c0000000-6300c9ffffff : PCI Bus 0006:02
>>>        6300c0000000-6300c8ffffff : PCI Bus 0006:03
>>>          6300c0000000-6300c1ffffff : 0006:03:00.0
>>>            6300c0000000-6300c1ffffff : mlx5_core
>>>          6300c2000000-6300c3ffffff : 0006:03:00.1
>>>            6300c2000000-6300c3ffffff : mlx5_core
>>>          6300c4000000-6300c47fffff : 0006:03:00.2
>>>          6300c4800000-6300c67fffff : 0006:03:00.0
>>>          6300c6800000-6300c87fffff : 0006:03:00.1
>>>        6300c9000000-6300c9bfffff : PCI Bus 0006:04
>>>          6300c9000000-6300c9bfffff : PCI Bus 0006:05
>>>            6300c9000000-6300c91fffff : PCI Bus 0006:06
>>>            6300c9200000-6300c93fffff : PCI Bus 0006:07
>>>            6300c9400000-6300c95fffff : PCI Bus 0006:08
>>>            6300c9600000-6300c97fffff : PCI Bus 0006:09
>>>
>>> After the commit:
>>> 6300c0000000-63ffffffffff : PCI Bus 0006:00
>>>    6300c0000000-6300c9ffffff : PCI Bus 0006:01
>>>      6300c0000000-6300c9ffffff : PCI Bus 0006:02
>>>        6300c0000000-6300c43fffff : PCI Bus 0006:03
>>>          6300c0000000-6300c1ffffff : 0006:03:00.0
>>>            6300c0000000-6300c1ffffff : mlx5_core
>>>          6300c2000000-6300c3ffffff : 0006:03:00.1
>>>            6300c2000000-6300c3ffffff : mlx5_core
>>>        6300c4400000-6300c4dfffff : PCI Bus 0006:04
>>>          6300c4400000-6300c4dfffff : PCI Bus 0006:05
>>>            6300c4400000-6300c45fffff : PCI Bus 0006:06
>>>            6300c4600000-6300c47fffff : PCI Bus 0006:07
>>>            6300c4800000-6300c49fffff : PCI Bus 0006:08
>>>            6300c4a00000-6300c4bfffff : PCI Bus 0006:09
>>>
>>> We can see that the window of 0006:03 gets shrunken too much and 0006:04
>>> eats away the window for 0006:03:00.2.
>>>
>>> The offending commit distributes the upstream bridge's resources
>>> multiple times to every downstream bridges, hence makes the aperture
>>> smaller than desired because calculation of io_per_b, mmio_per_b and
>>> mmio_pref_per_b becomes incorrect.
>>>
>>> Instead, distributing downstream bridges' own resources to resolve the
>>> issue.
>>>
>>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=219540
>>> Cc: Carol Soto <csoto@nvidia.com>
>>> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>>> Cc: Chris Chiu <chris.chiu@canonical.com>
>>> Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
>>
>> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> 
> Is it possible to pickup this up in 6.13 window?

Now 6.14 window is open, is it possible to include this fix?

Kai-Heng

> 
> Kai-Heng
Re: [PATCH v2] PCI: Use downstream bridges for distributing resources
Posted by Kai-Heng Feng 10 months, 1 week ago 

On 2025/1/20 2:39 PM, Kai-Heng Feng wrote:
> 
> 
> On 2024/12/18 7:12 PM, Kai-Heng Feng wrote:
>> Hi Bjorn,
>>
>> On 2024/12/4 1:48 PM, Mika Westerberg wrote:
>>> External email: Use caution opening links or attachments
>>>
>>>
>>> On Wed, Dec 04, 2024 at 10:24:57AM +0800, Kai-Heng Feng wrote:
>>>> Commit 7180c1d08639 ("PCI: Distribute available resources for root
>>>> buses, too") breaks BAR assignment on some devcies:
>>>> [   10.021193] pci 0006:03:00.0: BAR 0 [mem 0x6300c0000000-0x6300c1ffffff 
>>>> 64bit pref]: assigned
>>>> [   10.029880] pci 0006:03:00.1: BAR 0 [mem 0x6300c2000000-0x6300c3ffffff 
>>>> 64bit pref]: assigned
>>>> [   10.038561] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: 
>>>> can't assign; no space
>>>> [   10.047191] pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: 
>>>> failed to assign
>>>> [   10.055285] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: 
>>>> can't assign; no space
>>>> [   10.064180] pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: 
>>>> failed to assign
>>>> [   10.072543] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: 
>>>> can't assign; no space
>>>> [   10.081437] pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: 
>>>> failed to assign
>>>>
>>>> The apertures of domain 0006 before the commit:
>>>> 6300c0000000-63ffffffffff : PCI Bus 0006:00
>>>>    6300c0000000-6300c9ffffff : PCI Bus 0006:01
>>>>      6300c0000000-6300c9ffffff : PCI Bus 0006:02
>>>>        6300c0000000-6300c8ffffff : PCI Bus 0006:03
>>>>          6300c0000000-6300c1ffffff : 0006:03:00.0
>>>>            6300c0000000-6300c1ffffff : mlx5_core
>>>>          6300c2000000-6300c3ffffff : 0006:03:00.1
>>>>            6300c2000000-6300c3ffffff : mlx5_core
>>>>          6300c4000000-6300c47fffff : 0006:03:00.2
>>>>          6300c4800000-6300c67fffff : 0006:03:00.0
>>>>          6300c6800000-6300c87fffff : 0006:03:00.1
>>>>        6300c9000000-6300c9bfffff : PCI Bus 0006:04
>>>>          6300c9000000-6300c9bfffff : PCI Bus 0006:05
>>>>            6300c9000000-6300c91fffff : PCI Bus 0006:06
>>>>            6300c9200000-6300c93fffff : PCI Bus 0006:07
>>>>            6300c9400000-6300c95fffff : PCI Bus 0006:08
>>>>            6300c9600000-6300c97fffff : PCI Bus 0006:09
>>>>
>>>> After the commit:
>>>> 6300c0000000-63ffffffffff : PCI Bus 0006:00
>>>>    6300c0000000-6300c9ffffff : PCI Bus 0006:01
>>>>      6300c0000000-6300c9ffffff : PCI Bus 0006:02
>>>>        6300c0000000-6300c43fffff : PCI Bus 0006:03
>>>>          6300c0000000-6300c1ffffff : 0006:03:00.0
>>>>            6300c0000000-6300c1ffffff : mlx5_core
>>>>          6300c2000000-6300c3ffffff : 0006:03:00.1
>>>>            6300c2000000-6300c3ffffff : mlx5_core
>>>>        6300c4400000-6300c4dfffff : PCI Bus 0006:04
>>>>          6300c4400000-6300c4dfffff : PCI Bus 0006:05
>>>>            6300c4400000-6300c45fffff : PCI Bus 0006:06
>>>>            6300c4600000-6300c47fffff : PCI Bus 0006:07
>>>>            6300c4800000-6300c49fffff : PCI Bus 0006:08
>>>>            6300c4a00000-6300c4bfffff : PCI Bus 0006:09
>>>>
>>>> We can see that the window of 0006:03 gets shrunken too much and 0006:04
>>>> eats away the window for 0006:03:00.2.
>>>>
>>>> The offending commit distributes the upstream bridge's resources
>>>> multiple times to every downstream bridges, hence makes the aperture
>>>> smaller than desired because calculation of io_per_b, mmio_per_b and
>>>> mmio_pref_per_b becomes incorrect.
>>>>
>>>> Instead, distributing downstream bridges' own resources to resolve the
>>>> issue.
>>>>
>>>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=219540
>>>> Cc: Carol Soto <csoto@nvidia.com>
>>>> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>>>> Cc: Chris Chiu <chris.chiu@canonical.com>
>>>> Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
>>>
>>> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>>
>> Is it possible to pickup this up in 6.13 window?
> 
> Now 6.14 window is open, is it possible to include this fix?

Another gentle ping...

> 
> Kai-Heng
> 
>>
>> Kai-Heng
>

Patchew 2.1-devel-b67e4c2

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