diff mbox series

PCI: Use downstream bridges for distributing resources

Message ID 20241128084039.54972-1-kaihengf@nvidia.com (mailing list archive)
State New
Headers show
Series PCI: Use downstream bridges for distributing resources | expand

Commit Message

Kai-Heng Feng Nov. 28, 2024, 8:40 a.m. UTC
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: Matthew R. Ochs <mochs@nvidia.com>
Reviewed-by: Koba Ko <kobak@nvidia.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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Mika Westerberg Nov. 28, 2024, 9:45 a.m. UTC | #1
On Thu, Nov 28, 2024 at 04:40:39PM +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: Matthew R. Ochs <mochs@nvidia.com>
> Reviewed-by: Koba Ko <kobak@nvidia.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 | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 23082bc0ca37..2db19c17e824 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -2105,7 +2105,7 @@ pci_root_bus_distribute_available_resources(struct pci_bus *bus,
>  		 * in case of root bukjijs.
>  		 */
>  		if (bridge && pci_bridge_resources_not_assigned(dev))
> -			pci_bridge_distribute_available_resources(bridge,
> +			pci_bridge_distribute_available_resources(dev,
>  								  add_list);

I think it looks better if you put this into one line instead:

			pci_bridge_distribute_available_resources(dev, add_list);


Otherwise looks good. I wonder if you checked that this still works with
the cases 7180c1d08639 tried to solve? ;-)
>  		else
>  			pci_root_bus_distribute_available_resources(b, add_list);
> -- 
> 2.47.0
Kai-Heng Feng Nov. 28, 2024, 11:11 a.m. UTC | #2
On 2024/11/28 5:45 PM, Mika Westerberg wrote:
> External email: Use caution opening links or attachments
> 
> 
> On Thu, Nov 28, 2024 at 04:40:39PM +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: Matthew R. Ochs <mochs@nvidia.com>
>> Reviewed-by: Koba Ko <kobak@nvidia.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 | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
>> index 23082bc0ca37..2db19c17e824 100644
>> --- a/drivers/pci/setup-bus.c
>> +++ b/drivers/pci/setup-bus.c
>> @@ -2105,7 +2105,7 @@ pci_root_bus_distribute_available_resources(struct pci_bus *bus,
>>                 * in case of root bukjijs.
>>                 */
>>                if (bridge && pci_bridge_resources_not_assigned(dev))
>> -                     pci_bridge_distribute_available_resources(bridge,
>> +                     pci_bridge_distribute_available_resources(dev,
>>                                                                  add_list);
> 
> I think it looks better if you put this into one line instead:
> 
>                          pci_bridge_distribute_available_resources(dev, add_list);

Sure, will do.

> 
> 
> Otherwise looks good. I wonder if you checked that this still works with
> the cases 7180c1d08639 tried to solve? ;-)

That's why Chris is Cc'ed.
Chris, is it possible to give this patch a try to make sure this doesn't break 
what 7180c1d08639 solved?

Will send v2 after your test result.

Kai-Heng

>>                else
>>                        pci_root_bus_distribute_available_resources(b, add_list);
>> --
>> 2.47.0
diff mbox series

Patch

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 23082bc0ca37..2db19c17e824 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -2105,7 +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,
+			pci_bridge_distribute_available_resources(dev,
 								  add_list);
 		else
 			pci_root_bus_distribute_available_resources(b, add_list);