Messages in this thread Patch in this message |  | | From | Kai-Heng Feng <> | | Subject | [PATCH v2] PCI: Use downstream bridges for distributing resources | | Date | Wed, 4 Dec 2024 10:24:57 +0800 |
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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
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